New research at the McKelvey School of Engineering at Washington University in St. Louis is the first to show that a solid-state electrolyte has a high level of similarity to liquid electrolytes, which is good news for designing safer and more efficient solid-state batteries based on reliable mechanistic knowledge.&ldquo;Our results reveal surprising similarities between the liquid and the solid electrolytes, and that allows us to borrow some ideas from the successful liquid electrolytes to help our design of the solid electrolytes,&rdquo; said Peng Bai, assistant professor of energy, environmental &amp; chemical engineering. &ldquo;Before our work, solid electrolytes, at least the ceramic ones we studied here, are considered distinctly different from their liquid counterparts.&rdquo;Batteries power so much of our lives, so finding new improvements will have a drastic societal impact, Bai said. A promising route is the development of a full solid-state battery. A key component is the electrolyte in the center of the battery which allows ion movement between the electrodes. Here, the traditionally used liquid electrolyte is replaced with a solid and coupled to a metal electrode. This not only boosts the amount of energy stored but also leads to a potentially safer battery. However, an increasing number of reports about solid-state batteries tell a story of a key barrier, known as the critical current density (CCD), beyond which small tree-like structures called dendrites grow, resulting in battery failure. These reported CCDs are relatively low, which hinders fast charging and compromises further development of solid-state batteries.&ldquo;The CCD of solid-state electrolytes is a mystery. We are working to reveal why it exists, what its true physics are, and how it changes under different operating conditions,&rdquo; said Bai, the principal investigator of this project and corresponding author of the paper published in&nbsp;ACS Energy Letters on April 12, 2023.&ldquo;Our discovery shows that the magnitude of CCD is linked to the thickness of the solid electrolyte, similar to the limiting current in liquid electrolytes that are well-known to have thickness dependence,&rdquo; he said. &ldquo;If you can make the solid electrolyte thin enough, we can get away from this CCD issue, therefore avoiding dendrite growths and the internal short-circuiting.&rdquo;Experimental innovations involved in this study include taking a standard pellet, a small circular disc fully densified by controlled sintering of ceramic powders, and precisely cutting it into multiple smaller pieces. The pieces were then tested using an electroanalytical technique different from those commonly used.&ldquo;These child samples from the same mother pellet were almost identical,&rdquo; Bai said. &ldquo;Testing hundreds of these ideally consistent miniature samples made the results we obtained more reliable and the statistics more meaningful.&rdquo;Rajeev Gopal, a doctoral student in Bai&rsquo;s lab and first author of the paper, said this study can be a real difference-maker.&ldquo;Our work can shed light on the mysterious phenomenon of dendrite initiation at the CCD. The statistical trends we unveiled here will help predict and ultimately mitigate this type of growth, increasing the feasibility of these electrolytes in real-world batteries,&rdquo; Gopal said.<hr>Gopal R, Wu L, Lee Y, Gua J, Bai P. Transient Polarization and Dendrite Initiation Dynamics in Ceramic Electrolytes. ACS Energy Letters, April 12, 2023, DOI:&nbsp;<a href="https://pubs.acs.org/doi/10.1021/acsenergylett.3c00499" target="_blank">10.1021/acsenergylett.3c00499.</a>

Ceramic solid electrolyte cells (vertical rectangular shapes) with dendrites (the lightning-like dark structures inside the rectangles) growing inside them from the bottom to the top. These solid electrolytes are floating on a liquid (blue puddle) which represents a liquid electrolyte. The reflections of the solid electrolytes in the blue liquid, particularly the dark dendrites, show the similarity in the dendrite initiation process in both the liquid and solid. (Credit: Rajeev Gopal, Bai lab)

New research at the McKelvey School of Engineering at Washington University in St. Louis is the first to show that a solid-state electrolyte has a high level of similarity to liquid electrolytes, which is good news for designing safer and more efficient solid-state batteries based on reliable mechanistic knowledge.

New study shows similarity between solid state and liquid state electrolytes used in batteries

A formula that can draw important conclusions about a battery&rsquo;s internal components and condition from the way alternating currents move through it has been developed by Michigan Engineering researchers. It could help researchers identify battery faults during operation and design safer batteries.To ensure battery safety and performance, the industry needs effective techniques to monitor and diagnose a battery without tearing it apart. In a recent study that Applied Physics Letters highlighted as an editor&rsquo;s pick, a team led by Wei Lu, a professor of mechanical engineering, reported a formula that can do this with measurements of impedance, an electrical property that compares output voltage to input current.&nbsp;Until now, the relationship between impedance measurements and the internal state of the battery wasn&rsquo;t known well enough to be broadly useful. In addition, the formula can be applied to other electronic and photonic devices.&nbsp;The research team also includes first author Changyu Deng, a PhD student in mechanical engineering; Bogdan Epureanu, an Arthur F. Thurnau professor and professor of mechanical engineering; and Bogdan Popa, an associate professor of mechanical engineering.We sat down with Lu to find out more.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1682949990705-liu_ev_battery_content.jpg" style="width: 766px;" class="fr-fic fr-dib">Wei Lu cycling batteries in his lab in June 2022. Brenda Ahearn/Michigan Engineering&nbsp;<h2 id="isPasted">What does your formula tell battery researchers?</h2>Batteries are complicated systems made of many materials, including two electrodes that are two different materials, the membrane between them, and the electrolyte that carries ions from one electrode to the other during charging and discharging.&nbsp;An important technique that researchers rely on when investigating batteries is applying an alternating current to probe the battery. This is the same kind of current you get from a wall plug, though much weaker, and the impedance changes depending on the frequency of the alternating current, or how quickly the current changes its flow directions.One key measure is how impedance varies with frequency, or an impedance-frequency signature curve. We obtain it by sweeping the frequency from low to high, or millihertz to kilohertz frequencies. This curve is important because it is closely related to the internal material condition and state of the battery. It can be used to diagnose a battery for early fault warning or design better, safer batteries using the measured data. However, to make this work, it is necessary to build a relationship between the signature and the battery materials. &nbsp;Therefore, we came up with our own formula to describe the relationship, and it works for any combination of battery materials. After measuring impedance at a few frequencies, the formula can predict impedance as a function of frequency for a wide range frequency range.<h2>How will this formula help design new, better batteries?</h2>The formula serves as a tool to express material impedance from a few experimental data points. It simplifies the way to model how electricity moves through devices made with many materials, including batteries but also other electronic and photonic devices. Unlike earlier formulas, it doesn&rsquo;t need to know the microstructure of the material in advance.In battery development, the theory behind the formula helps researchers to understand the mechanisms that govern the performance of solid-state electrolytes, helping them to discover new and better electrolytes. Solid state electrolytes could make EV batteries safer, as liquid electrolytes are typically flammable.The formula can also help guide which measurements a research team should make next, enabling teams to be more efficient as they design better solid electrolytes. By isolating the impedance of solid-state electrolytes, the formula can also help researchers to pinpoint the impedance features of other components of batteries, such as electrodes, and tune them for better designs.Beyond the battery design stage, engineers can use the formula to help build concise and accurate models of the battery in the battery management system to deliver safer and more efficient control during charging and discharging.<h2>What are your next steps?</h2>We are going to incorporate this formula in our battery work. We have been working on explaining how solid-state electrolytes, a material for next-generation lithium batteries, transport ions. This is a key function, as the movement of ions within the battery drives electrons through the circuit to power devices. We plan to use this formula to understand and design solid state electrolytes with mixed materials, which can provide higher capacity and better safety.

A new formula makes sense of the way batteries respond to different alternating current frequencies, revealing materials, structures, faults and more.

Testing batteries for safety and performance without opening them up

The world needs cheap and powerful batteries that can store sustainably produced electricity from wind or sunlight so that we can use it whenever we need it, even when it&#39;s dark outside or there&#39;s no wind blowing. Most common batteries that power our smartphones and electric cars are lithium-ion batteries. These are quite expensive because worldwide demand for lithium is soaring, and these batteries are also highly flammable.Water-based Zinc batteries offer a promising alternative to these lithium-ion batteries. An international team of researchers led by ETH Zurich has now devised a strategy that brings key advances to the development of such zinc batteries, making them more powerful, safer and more environmentally friendly.<h2>Durability is a challenge</h2>There is a number of advantages to Zinc batteries: Zinc is abundant, cheap and has mature recycling infrastructure. Furthermore, zinc batteries can store a lot of electricity. &nbsp;Most importantly, zinc batteries don&rsquo;t necessarily require the use of highly flammable organic solvents as the electrolyte fluid, as they can also be made using water-based electrolytes instead.If only there weren&rsquo;t challenges that engineers must face with when developing these batteries: when zinc batteries are charged at high voltage, the water in electrolyte fluid reacts on one of the electrodes to form hydrogen gas. When this happens, the electrolyte fluid dwindles and battery performance decreases. Furthermore, this reaction causes excess pressure to build up in the battery that can be dangerous. Another issue is formation of spikey deposits of Zinc during charging of the battery, known as dendrites, that can pierce through the battery and in the worst case even cause short circuit and render the battery unusable.<h2>Salts make batteries toxic</h2>In recent years, engineers have pursued the strategy of enriching the aqueous liquid electrolyte with salts in order to keep the water content as low as possible. But there are also disadvantages to this: It makes the electrolyte fluid viscous, which slows down the charging and discharging processes considerably. In addition, many of the salts used contain fluorine, making them toxic and harmful to the environment.Maria Lukatskaya, Professor of Electrochemical Energy Systems at ETH Zurich, has now joined forces with colleagues from several research institutions in the United States and Switzerland to systematically search for the ideal salt concentration for water-based zinc-ion batteries. Using experiments supported by computer simulations, the researchers were able to reveal that the ideal salt concentration is not, as was previously assumed, the highest one possible, but a relatively low one: five to ten water molecules per salt&rsquo;s positive ion.<h2>Long-lasting performance and fast charging</h2>What&rsquo;s more, the researchers didn&rsquo;t use any environmentally harmful salts for their improvements, opting instead for environmentally friendly salts of acetic acid, called acetates. &ldquo;With an ideal concentration of acetates, we were able to minimise electrolyte depletion and prevent Zinc dendrites just as well as other scientists previously did with high concentrations of toxic salts,&rdquo; says Dario Gomez Vazquez, a doctoral student in Lukatskaya&rsquo;s group and lead author of the study. &ldquo;Moreover, with our approach, the batteries can be charged and discharged much faster.&rdquo;So far, the ETH researchers have tested their new battery strategy on a relatively small laboratory scale. The next step will be to scale up the approach and see if it can also be translated for large batteries. Ideally, these might one day be used as storage units in the power grid to compensate for fluctuations, say, or in the basements of single-family homes to allow solar power produced during the day to be used in the evening. There are still some challenges to overcome before zinc batteries will be ready for the market, as ETH Professor Lukatskaya explains: batteries consist of two electrodes &ndash; the anode and the cathode &ndash; and the electrolyte fluid between them. &ldquo;We showed that by tuning electrolyte composition efficient charging of Zinc anodes can be enabled,&rdquo; she says. &ldquo;Going forward, however, performance cathode materials will have to be optimised as well to realize durable and efficient zinc batteries.&rdquo;<hr><h2 id="isPasted">Reference</h2><a href="https://pubs.rsc.org/en/results?searchtext=Author%3ADario%20Gomez%20Vazquez" target="_blank">external pageGomez Vazquezcall_made</a> D, <a href="https://pubs.rsc.org/en/results?searchtext=Author%3ATravis%20P.%20Pollard" target="_blank">external pagePollardcall_made</a> TP, <a href="https://pubs.rsc.org/en/results?searchtext=Author%3AJulian%20Mars" target="_blank">external pageMarscall_made</a> J, <a href="https://pubs.rsc.org/en/results?searchtext=Author%3AJi%20Mun%20Yoo" target="_blank">external pageYoocall_made</a> JM, <a href="https://pubs.rsc.org/en/results?searchtext=Author%3AHans-Georg%20Steinr%C3%BCck" target="_blank">external pageSteinr&uuml;ckcall_made</a> HG, <a href="https://pubs.rsc.org/en/results?searchtext=Author%3ASharon%20E.%20Bone" target="_blank">external pageBonecall_made</a> SE, <a href="https://pubs.rsc.org/en/results?searchtext=Author%3AOlga%20V.%20Safonova" target="_blank">external pageSafonovacall_made</a> OV, <a href="https://pubs.rsc.org/en/results?searchtext=Author%3AMichael%20F.%20Toney" target="_blank">external pageToneycall_made</a> MF, <a href="https://pubs.rsc.org/en/results?searchtext=Author%3AOleg%20Borodin" target="_blank">external pageBorodincall_made</a> O, <a href="https://pubs.rsc.org/en/results?searchtext=Author%3AMaria%20R.%20Lukatskaya" target="_blank">external pageLukatskayacall_made</a> MR: Creating water-in-salt-like environment using coordinating anions in non-concentrated aqueous electrolytes for efficient Zn batteries. Energy &amp; Environmental Science, 13 March 2023, doi: <a href="https://doi.org/10.1039/D3EE00205E" target="_blank">external page10.1039/D3EE00205E</a>

Zinc batteries are considered promising alternatives to lithium-​ion batteries. (Visualisations: ETH Zurich / Xin Zou)

It is not easy to make batteries cheap, efficient, durable, safe and environmentally friendly at the same time. Researchers at ETH Zurich have now succeeded in uniting all of these characteristics in zinc metal batteries.

Progress in alternative battery technology

It can be a difficult decision when deciding whether to utilize batteries or supercapacitors. Batteries offer a steady source of power but can suffer from their capacity degrading over time. On the other hand, supercapacitors provide quick charging and discharging capabilities but are limited when it comes to long duration storage capacity. This challenge is why many are making the change to hybrid systems that combine the best properties of batteries and supercapacitors to create an efficient and dependable power solution. Let&#39;s dive in to the differences between batteries and&nbsp;supercapacitors, hybrid energy storage systems that utilize both of them, and how Capacitech&rsquo;s products overcome difficulties, offering their customers the storage system of the future.Before we go into detail, here is a quick summary:<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1681741136016-Screenshot+2023-04-17+101851.png" style="width: 688px;" class="fr-fic fr-dib"><h3>What are batteries?</h3><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1681741294902-Screenshot+2023-04-17+102129.png" style="width: 626px;" class="fr-fic fr-dib">Batteries are energy storage devices that use electrochemical reactions to store electrical energy as chemical energy, which can then be converted back into electricity when needed. Batteries have a relatively high energy density compared to other forms of energy storage, making them the perfect option for many applications that need long-term storage. They also have a low self-discharge rate, meaning that when they are not in use, they only lose a small percentage of charge.&nbsp;Although batteries offer several advantages over other forms of energy storage, they have some disadvantages as well. As a result of energy in batteries being stored as chemical energy, the power density tends to be lower than some other energy storage devices, meaning it cannot quickly deliver a large quantity of energy in a short period of time. Batteries that are exposed to loads that require bursts of power can degrade quickly, wasting their capacity and even shortening their operating life. Batteries also typically have a short cycle life, which depending on their chemistry can be as short as 500 cycles. <h3>What are supercapacitors?</h3><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1681741340674-Screenshot+2023-04-17+102214.png" style="width: 676px;" class="fr-fic fr-dib">Supercapacitors are another energy storage technology. Unlike batteries, supercapacitors store most of their energy electrostatically. As a result of this, they can charge and discharge energy much quicker than batteries, with power densities typically 10 times greater.The biggest advantage of a supercapacitor is its high power density, which allows it to supply large amounts of power in short bursts. This makes them perfect for applications that require quick bursts of energy such as starting a pump or motor. Since there are no chemical reactions in a supercapacitor&rsquo;s energy storage process, their lifespans tend to be much longer than that of a battery, reaching cycle lives of up to one million.Supercapacitors are more stable across a wider range of temperatures compared to batteries, allowing them to be used in locations with extreme temperatures. They can be operated in temperatures that range from -40C to 65C (-40F to 149F), whereas batteries like the Panasonic NCR18650GA Li-ion battery can only be operated in temperatures from 0C to 45C (32F to 113F).&nbsp;Supercapacitors, like batteries, have disadvantages of their own. They have a much lower energy density than batteries making them unsuitable for applications requiring long-term storage of energy. Supercapacitors also have a high self-discharge rate, meaning that when they are not in use, they tend to lose a large percentage of their charge. They are also typically more expensive than batteries.&nbsp; <h3>What are the benefits of using a hybrid system?</h3>By combining the complementary advantages of batteries and supercapacitors, these two systems can be a perfect fit in applications with dynamic, fluctuating loads that also have longer duration storage requirements. Cleantech applications like electric tug boats or solar farms operating in areas with moving cloud coverage are prime candidates.&nbsp;As mentioned before, supercapacitors are well suited for applications that require quick bursts of power, such as starting a motor or providing peak power demands for brief periods. These devices can charge and discharge very large amounts of power in short periods of time, making them perfect for short-term or &quot;turn-on&quot; needs, like accelerating an electric scooter. Batteries on the other hand, are great for contributing steady, longer-term power, which can provide the steady-state power needed to keep the electric scooter running, for example.When used together in a hybrid energy storage system, the two technologies can allow for a more stable system as well as support each other&rsquo;s strengths. <h3 id="isPasted">What are the tradeoffs of using a hybrid system?</h3>&nbsp;Hybrid systems do not come without tradeoffs of their own; one of the most prominent being the lack of physical space for it. Size and space restrictions tend to cause designers to pick one energy storage technology over the other, rather than having both. Batteries and supercapacitors compete for space in an energy storage system. On a solar farm, for example, a certain amount of space may be allocated for long-duration storage (batteries). To add supercapacitors to this farm, which would provide the extra power needed to keep loads on during periods of moving cloud coverage, designers would have to either get rid of batteries to making space for the supercapacitors (less long-duration storage), increase the size of the energy storage container (less space for solar panels), or invest in more property (added cost).&nbsp; <h3>Capacitech&rsquo;s Power Storage Cable revolutionizes hybrid systems</h3>Capacitech&#39;s Power Storage Cable is designed to alleviate the engineering tradeoffs that make combining batteries and supercapacitors a challenge. The Power Storage Cable conceals supercapacitors and power electronics inside a power cord, allowing for any design tradeoffs typically associated with creating a hybrid system to be avoided, providing customers with a chance to use space that is not traditionally used for energy storage. This allows for the creation of a discrete and distributed network of supercapacitors running between solar panels, batteries, inverters, and the loads in which they are powering. Our cables provide the advantages of supercapacitors to provide the ideal energy storage system, allowing for a higher level of efficiency and flexibility in energy storage systems without the typical tradeoffs of hybrid systems.

Batteries are great, but they are not perfect. The same can be said about supercapacitors. Actually, where one is strong the other is weak. This is why there is growing interest in using both at the same time, but that can be challenging. In this article, we talk about differences between batteries, supercapacitors, hybrids, and how Capacitech’s unique approach to energy storage systems overcomes challenges faced in the past. 

Batteries or Supercapacitors? Why Not Both?

Researchers at Texas A&amp;M University have discovered a 1,000% difference in the storage capacity of metal-free, water-based battery electrodes.These batteries are different from lithium-ion batteries that contain cobalt. The group&#39;s goal of researching metal-free batteries stems from having better control over the domestic supply chain since cobalt and lithium are outsourced. This safer chemistry would also prevent battery fires.Chemical engineering professor Dr. Jodie Lutkenhaus and chemistry assistant professor Dr. Daniel Tabor has published their findings about lithium-free batteries in<a href="https://www.nature.com/articles/s41563-023-01518-z" rel="noopener" target="_blank">&nbsp;Nature Materials</a><a href="https://www.nature.com/articles/s41563-023-01518-z" target="_blank">.</a>&nbsp;&ldquo;There would be no battery fires anymore because it&#39;s water-based,&rdquo; Lutkenhaus said. &ldquo;In the future, if materials shortages are projected, the price of lithium-ion batteries will go way up. If we have this alternative battery, we can turn to this chemistry, where the supply is much more stable because we can manufacture them here in the United States and materials to make them are here.&rdquo;&nbsp;Lutkenhaus said aqueous batteries consist of a cathode, electrolyte and an anode. The cathodes and anodes are polymers that can store energy, and the electrolyte is water mixed with organic salts. The electrolyte is key to ion conduction and energy storage through its interactions with the electrode.&ldquo;If an electrode swells too much during cycling, then it can&#39;t conduct electrons very well, and you lose all the performance,&rdquo; she said. &ldquo;I believe there is a 1,000% difference in energy storage capacity, depending on the electrolyte choice because of swelling effects.&rdquo;According to their article, redox-active, non-conjugated radical polymers (electrodes) are promising candidates for metal-free aqueous batteries because of the polymers&rsquo; high discharge voltage and fast redox kinetics. The reaction is complex and difficult to resolve because of the simultaneous transfer of electrons, ions and water molecules.&ldquo;We demonstrate the nature of the redox reaction by examining aqueous electrolytes of varying chao-/kosmotropic character using electrochemical quartz crystal microbalance with dissipation monitoring at a range of timescales,&rdquo; according to researchers in the article.Tabor&rsquo;s research group complemented the experimental efforts with computational simulation and analysis. The simulations gave insights into the microscopic molecular-scale picture of the structure and dynamics.&ldquo;Theory and experiment often work closely together to understand these materials. One of the new things that we do computationally in this paper is that we actually charge up the electrode to multiple states of charge and see how the surroundings respond to this charging,&rdquo; Tabor said.Researchers macroscopically observed if the battery cathode was working better in the presence of certain kinds of salts through measuring exactly how much water and salt is going into the battery as it is operating.&ldquo;We would like to expand our simulations to future systems. We needed to have our theory confirmed of what are the forces that are driving that kind of injection of water and solvent,&quot; Tabor said. &ldquo;With this new energy storage technology, this is a push forward to lithium-free batteries. We have a better molecular level picture of what makes some battery electrodes work better than others, and this gives us strong evidence of where to go forward in materials design.&quot;&nbsp;

Chemical engineering professor Dr. Jodie Lutkenhaus and chemistry assistant professor Dr. Daniel Tabor have discovered significant storage capacity in water-based batteries. | Image: Texas A&M Engineering

Researchers at Texas A&M University have discovered a 1,000% difference in the storage capacity of metal-free, water-based battery electrodes.

Team finds major storage capacity in water-based batteries

Recovering up to 70 percent of the lithium from battery waste without the need for corrosive chemicals, high temperatures or prior sorting of the materials: This is made possible by a recycling process developed at the Karlsruhe Institute of Technology (KIT) that combines mechanical processes and chemical reactions. The method allows a wide variety of lithium-ion batteries to be recycled in a cost-effective, energy-efficient and environmentally friendly manner. The researchers report in the journal Nature Communications Chemistry ( <a href="https://doi.org/10.1038/s42004-023-00844-2" target="_blank">DOI: 10.1038/s42004-023-00844-2</a> )&nbsp;Lithium-ion batteries permeate our everyday life: They not only supply notebooks and smartphones, toys, remote controls and other small devices with wireless power, but also act as the most important energy storage medium for the rapidly growing electromobility. The increasing use of these batteries calls for economically and ecologically sustainable recycling methods. Today, mainly nickel and cobalt, copper and aluminum as well as steel are recovered and recycled from battery waste. The recovery of lithium is currently still expensive and not very profitable. The available, mostly metallurgical processes consume a lot of energy and/or leave behind harmful by-products. In contrast, approaches in mechanochemistry, which use mechanical processes to bring about chemical reactions, promise&nbsp;<h2>Suitable for different cathode materials</h2>Such a method has now been developed by the Institute for Applied Materials - Energy Storage Systems (IAM-ESS) of KIT together with the Helmholtz Institute Ulm for Electrochemical Energy Storage (HIU) founded by KIT in cooperation with the University of Ulm and EnBW Energie Baden-W&uuml;rttemberg AG . In the journal Nature Communications Chemistrythe researchers present their method.&nbsp;You can achieve a recovery rate of up to 70 percent for the lithium without the need for corrosive chemicals, high temperatures or prior sorting of the materials.&nbsp;&quot;The process is suitable for recovering lithium from cathode materials with different chemical compositions and is therefore suitable for many different commercially available lithium-ion batteries,&quot; explains Dr.&nbsp;Oleksandr Dolotko from the IAM-ESS of the KIT and from the HIU, main author of the publication.&nbsp;&quot;It allows for cost-effective, energy-efficient and environmentally friendly recycling.&quot;<h2>Reaction takes place at room temperature&nbsp;</h2>For their process, the researchers use aluminum as a reducing agent in the mechanochemical reaction. Since aluminum is already contained in the cathode, the process does not require any additional substances. How it works: The battery waste is first ground up. Then they are used in a reaction with aluminum to create metallic composites with water-soluble lithium compounds. The lithium is then recovered by dissolving the water-soluble compounds in water and then heating to remove the water through evaporation. Since the mechanochemical reaction takes place at ambient temperature and pressure, the process is particularly energy-efficient. Another advantage is the simple process, which will facilitate use on an industrial scale.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1680261956042-2023_015_Batterierecycling+70+Prozent+des+Lithiums+zurueckgewonnen_2_72dpi.jpg" style="width: 766px;" class="fr-fic fr-dib">The more batteries there are for recycling, the more important sustainable recycling processes for the recyclable materials they contain become. (Photo: Amadeus Bramsiepe, KIT)&nbsp;<hr>Original publication (Open Access)&nbsp;Oleksandr Dolotko, Niclas Gehrke, Triantafillia Malliaridou, Raphael Sieweck, Laura Herrmann, Bettina Hunzinger, Michael Knapp &amp; Helmut Ehrenberg: Universal and efficient extraction of lithium for lithium-ion battery recycling using mechanochemistry. Communications Chemistry, 2023. DOI: 10.1038/s42004-023-00844-2&nbsp;

dr Oleksandr Dolotko, lead author of the publication, conducts research at the IAM-ESS Institute and the HIU. (Photo: Amadeus Bramsiepe, KIT)

KIT researchers develop inexpensive and environmentally friendly mechanochemical recycling process - publication in Nature Communications Chemistry

Battery recycling: 70 percent of the lithium recovered

<html><head></head><body>Off-grid events are becoming increasingly popular, and Red Bull's annual event Rampage is no exception. The home to some of the best mountain biking courses in the world is in the middle of the desert in Utah, where the nearest power outlet is miles away. Critical parts of the event were powered by batteries and solar panels rather than gas generators, which is a true testament to how far renewable energy technology has come in recent years. Capacitech was hired to address the shortcomings of batteries to power media equipment, a drone charging station, and ovens so that this off-grid event could take place without any issues. Let’s take a look at how Red Bull's off-grid event was powered by batteries, solar panels, and Capacitech’s Power Storage Cables.&nbsp;The Benefits of Using Batteries and Solar PanelsWhen Red Bull wanted to power their freeride mountain bike competition, Rampage, they opted to use batteries and solar panels to power parts of their event. Choosing batteries and solar as gas generator alternatives is a smart choice for a number of reasons. Gas generators are noisy and give off unpleasant odors, which can ruin the spectator’s experience. Additionally, they require someone to keep them topped off with gasoline which is costly and bad for the environment. Even when little to no power is being used, idling generators still consume gas, which is an expensive and limited resource when you are miles from the nearest gas station. In an effort to conserve gas,&nbsp;generators need to be turned off at night, further reducing power access at the event for night crews to use.Solar panels and batteries are an odor and noise-free alternative. We go deep into these benefits in one of our articles on this topic. <a href="https://www.capacitechenergy.com/blog/the-best-events-are-powered-by-clean-off-grid-energy-storage" target="_blank">Check it out here.</a> The basics of it are that sunlight powers the load (equipment like walkie-talkie chargers, laptops, small TVs, etc...) and charges the batteries. When extra energy is needed or a cloud passes overhead, the batteries discharge, providing the electrical power required to sustain the equipment the system is powering. This is an environmentally friendly and cost-saving option that should be highly considered for powering outdoor events.&nbsp;&nbsp;The Challenges of Using Batteries and Solar PanelsHowever, when using batteries and solar panels to power an event like Red Bull Rampage, there can be a few challenges. While batteries are great options for charging laptops or phones, they struggle to power equipment that need a large burst of power to turn on. Batteries are not designed for this kind of sudden delivery of large amounts of power, but equipment like speakers, jumbotrons, fast-charging drones, and ovens require it. This is where Capacitech comes in. At Rampage, our job was to ensure that drone charging stations, water filtration systems, and ovens used to bake s’mores were operational, without needing to oversize the battery system.How’d we do it? We use an incredible technology called a supercapacitor, which is hidden inside Capacitech's Power Storage Cables where they don’t compete for space with other equipment or batteries. Supercapacitors can quickly deliver large amounts of power, so they are the ideal device for providing the turn-on power required by equipment typical of outdoor events. By using a combination of batteries and supercapacitors, Red Bull Rampage was able to have a successful off-grid event powered by renewable energy sources.&nbsp;Power Storage Cables to the RescueInverters are an integral part of powering off-grid events. Inverters convert the DC voltage from the batteries and supercapacitors into AC voltage to power the equipment. Inverters have a working voltage window, and if the DC input voltage to the inverter is too low, it does not deliver the correct AC output voltage. This results in the equipment either not turning on or improperly functioning.So why is it so hard to use batteries to power certain kinds of loads? It is because they have a high internal resistance. When a high-powered load is connected to a battery, like plugging in a drone battery to charge, there will be a large instantaneous drop in the battery's voltage. That voltage drop is too low for the inverter, leading to the wrong AC output voltage. This was the case about 5% of the time at Red Bull Rampage (the times when the equipment was being plugged in or turned on), the battery voltage was about 20% lower than it should have been. Given the load needs a certain amount of power, the response is to draw more current out of the battery to compensate for the low voltage. This only worsens the issue.&nbsp;Power Storage Cables to the rescue. As mentioned before, Capacitech's Power Storage Cables utilize supercapacitor technologies. Supercapacitors have a significantly lower internal resistance than batteries do, which is one of the key differences between batteries and supercapacitors. It is also why supercapacitors are so good at instantaneously delivering high levels of power. Pairing them together reduces the system's overall internal resistance, resulting in a smaller instantaneous voltage drop when turning on equipment. This enables the system to provide the correct DC voltage to the inverter and avoids all these issues to provide reliable power storage. This is important in more areas than you think. It’s not just drone charging stations, but this approach was also used to power water filtration systems through the night (after hours when all the gas-powered generators were turned off) and also ovens in a farmer’s market-like setting used to bake s’mores.&nbsp; <iframe width="640" height="360" src="https://www.youtube.com/embed/M_yWynSUpoM?&amp;embeds_euri=https%3A%2F%2Fwww.capacitechenergy.com%2F&amp;feature=emb_logo&amp;wmode=opaque&amp;rel=0&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" frameborder="0" allowfullscreen="" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe> The Future of Off-Grid EventsEvents like college tailgates and music festivals are powered by gas generators every day. However, it is time to turn towards a more environmentally friendly alternative. It is time to replace gas generators and power more than just phones and laptops with solar panels and batteries. From jumbotrons to speaker systems, Capacitech’s Power Storage Cables enable solar panels and batteries to power almost anything at outdoor events!Making use of the superpowers of supercapacitors, Capacitech's Power Storage Cables help solar panels and batteries do more. So, the next time you're at an outdoor event, take a look at what's powering it. It may very well be powered by solar panels and batteries, made possible by Capacitech's Power Storage Cables!&nbsp;</body></html>

This was a mission-critical test case for Red Bull. The goal was to recharge the drone batteries quickly, needing high levels of power. The battery generator did not have the peak power required nor the power quality to complete the task on its own, but in combination with Capacitech's products, the system worked without a hitch!

Red Bull and Capacitech Redefine Boundaries of Cleantech with Solar, Batteries, and Supercapacitors

This article was first published on <a href="https://news.mit.edu/2023/using-combustion-make-better-batteries-0216" id="isPasted" rel="noopener noreferrer" target="_blank">MIT News</a>. &nbsp;&nbsp;<hr>For more than a century, much of the world has run on the combustion of fossil fuels. Now, to avert the threat of climate change, the energy system is changing. Notably, solar and wind systems are replacing fossil fuel combustion for generating electricity and heat, and batteries are replacing the internal combustion engine for powering vehicles. As the energy transition progresses, researchers worldwide are tackling the many challenges that arise.Sili Deng has spent her career thinking about combustion. Now an assistant professor in the MIT Department of Mechanical Engineering and the Class of 1954 Career Development Professor, Deng leads a group that, among other things, develops theoretical models to help understand and control combustion systems to make them more efficient and to control the formation of emissions, including particles of soot.&ldquo;So we thought, given our background in combustion, what&rsquo;s the best way we can contribute to the energy transition?&rdquo; says Deng. In considering the possibilities, she notes that combustion refers only to the process &mdash; not to what&rsquo;s burning. &ldquo;While we generally think of fossil fuels when we think of combustion, the term &lsquo;combustion&rsquo; encompasses many high-temperature chemical reactions that involve oxygen and typically emit light and large amounts of heat,&rdquo; she says.Given that definition, she saw another role for the expertise she and her team have developed: They could explore the use of combustion to make materials for the energy transition. Under carefully controlled conditions, combusting flames can be used to produce not polluting soot, but rather valuable materials, including some that are critical in the manufacture of lithium-ion batteries.<h2>Improving the lithium-ion battery by lowering costs</h2>The demand for lithium-ion batteries is projected to skyrocket in the coming decades. Batteries will be needed to power the growing fleet of electric cars and to store the electricity produced by solar and wind systems so it can be delivered later when those sources aren&rsquo;t generating. Some experts project that the global demand for lithium-ion batteries may increase tenfold or more in the next decade.Given such projections, many researchers are looking for ways to improve the lithium-ion battery technology. Deng and her group aren&rsquo;t materials scientists, so they don&rsquo;t focus on making new and better battery chemistries. Instead, their goal is to find a way to lower the high cost of making all of those batteries. And much of the cost of making a lithium-ion battery can be traced to the manufacture of materials used to make one of its two electrodes &mdash; the cathode.The MIT researchers began their search for cost savings by considering the methods now used to produce cathode materials. The raw materials are typically salts of several metals, including lithium, which provides ions &mdash; the electrically charged particles that move when the battery is charged and discharged. The processing technology aims to produce tiny particles, each one made up of a mixture of those ingredients, with the atoms arranged in the specific crystalline structure that will deliver the best performance in the finished battery.For the past several decades, companies have manufactured those cathode materials using a two-stage process called coprecipitation. In the first stage, the metal salts &mdash; excluding the lithium &mdash; are dissolved in water and thoroughly mixed inside a chemical reactor. Chemicals are added to change the acidity (the pH) of the mixture, and particles made up of the combined salts precipitate out of the solution. The particles are then removed, dried, ground up, and put through a sieve.A change in pH won&rsquo;t cause lithium to precipitate, so it is added in the second stage. Solid lithium is ground together with the particles from the first stage until lithium atoms permeate the particles. The resulting material is then heated, or &ldquo;annealed,&rdquo; to ensure complete mixing and to achieve the targeted crystalline structure. Finally, the particles go through a &ldquo;deagglomerator&rdquo; that separates any particles that have joined together, and the cathode material emerges.Coprecipitation produces the needed materials, but the process is time-consuming. The first stage takes about 10 hours, and the second stage requires about 13 hours of annealing at a relatively low temperature (750 degrees Celsius). In addition, to prevent cracking during annealing, the temperature is gradually &ldquo;ramped&rdquo; up and down, which takes another 11 hours. The process is thus not only time-consuming but also energy-intensive and costly.For the past two years, Deng and her group have been exploring better ways to make the cathode material. &ldquo;Combustion is very effective at oxidizing things, and the materials for lithium-ion batteries are generally mixtures of metal oxides,&rdquo; says Deng. That being the case, they thought this could be an opportunity to use a combustion-based process called flame synthesis.<h2>A new way of making a high-performance cathode material</h2>The first task for Deng and her team &mdash; mechanical engineering postdoc Jianan Zhang, Valerie L. Muldoon &rsquo;20, SM &rsquo;22, and current graduate students Maanasa Bhat and Chuwei Zhang &mdash; was to choose a target material for their study. They decided to focus on a mixture of metal oxides consisting of nickel, cobalt, and manganese plus lithium. Known as &ldquo;NCM811,&rdquo; this material is widely used and has been shown to produce cathodes for batteries that deliver high performance; in an electric vehicle, that means a long driving range, rapid discharge and recharge, and a long lifetime. To better define their target, the researchers examined the literature to determine the composition and crystalline structure of NCM811 that has been shown to deliver the best performance as a cathode material.They then considered three possible approaches to improving on the coprecipitation process for synthesizing NCM811: They could simplify the system (to cut capital costs), speed up the process, or cut the energy required.&ldquo;Our first thought was, what if we can mix together all of the substances &mdash; including the lithium &mdash; at the beginning?&rdquo; says Deng. &ldquo;Then we would not need to have the two stages&rdquo; &mdash; a clear simplification over coprecipitation.<h2>Introducing FASP</h2>One process widely used in the chemical and other industries to fabricate nanoparticles is a type of flame synthesis called flame-assisted spray pyrolysis, or FASP. Deng&rsquo;s&nbsp;<a href="https://www.sciencedirect.com/science/article/abs/pii/S0378775322002622?via%3Dihub" target="_blank">concept</a> for using FASP to make their targeted cathode powders proceeds as follows.The precursor materials &mdash; the metal salts (including the lithium) &mdash; are mixed with water, and the resulting solution is sprayed as fine droplets by an atomizer into a combustion chamber. There, a flame of burning methane heats up the mixture. The water evaporates, leaving the precursor materials to decompose, oxidize, and solidify to form the powder product. The cyclone separates particles of different sizes, and the baghouse filters out those that aren&rsquo;t useful. The collected particles would then be annealed and deagglomerated.To investigate and optimize this concept, the researchers developed a lab-scale FASP setup consisting of a homemade ultrasonic nebulizer, a preheating section, a burner, a filter, and a vacuum pump that withdraws the powders that form. Using that system, they could control the details of the heating process: The preheating section replicates conditions as the material first enters the combustion chamber, and the burner replicates conditions as it passes the flame. That setup allowed the team to explore operating conditions that would give the best results.Their experiments showed marked benefits over coprecipitation. The nebulizer breaks up the liquid solution into fine droplets, ensuring atomic-level mixing. The water simply evaporates, so there&rsquo;s no need to change the pH or to separate the solids from a liquid. As Deng notes, &ldquo;You just let the gas go, and you&rsquo;re left with the particles, which is what you want.&rdquo; With lithium included at the outset, there&rsquo;s no need for mixing solids with solids, which is neither efficient  nor effective.They could even control the structure, or &ldquo;morphology,&rdquo; of the particles that formed. In one series of experiments, they tried exposing the incoming spray to different rates of temperature change over time. They found that the temperature &ldquo;history&rdquo; has a direct impact on morphology. With no preheating, the particles burst apart; and with rapid preheating, the particles were hollow. The best outcomes came when they used temperatures ranging from 175-225 C. Experiments with coin-cell batteries (laboratory devices used for testing battery materials) confirmed that by adjusting the preheating temperature, they could achieve a particle morphology that would optimize the performance of their materials.Best of all, the particles formed in seconds. Assuming the time needed for conventional annealing and deagglomerating, the new setup could synthesize the finished cathode material in half the total time needed for coprecipitation. Moreover, the first stage of the coprecipitation system is replaced by a far simpler setup &mdash; a savings in capital costs.&ldquo;We were very happy,&rdquo; says Deng. &ldquo;But then we thought, if we&rsquo;ve changed the precursor side so the lithium is mixed well with the salts, do we need to have the same process for the second stage? Maybe not!&rdquo;<h2>Improving the second stage</h2>The key time- and energy-consuming step in the second stage is the annealing. In today&rsquo;s coprecipitation process, the strategy is to anneal at a low temperature for a long time, giving the operator time to manipulate and control the process. But running a furnace for some 20 hours &mdash; even at a low temperature &mdash; consumes a lot of energy.Based on their studies thus far, Deng thought, &ldquo;What if we slightly increase the temperature but reduce the annealing time by orders of magnitude? Then we could cut energy consumption, and we might still achieve the desired crystal structure.&rdquo;However, experiments at slightly elevated temperatures and short treatment times didn&rsquo;t bring the results they had hoped for. In transmission electron microscope (TEM) images, the particles that formed had clouds of light-looking nanoscale particles attached to their surfaces. When the researchers performed the same experiments without adding the lithium, those nanoparticles didn&rsquo;t appear. Based on that and other tests, they concluded that the nanoparticles were pure lithium. So, it seemed like long-duration annealing would be needed to ensure that the lithium made its way inside the particles.But they then came up with a different solution to the lithium-distribution problem. They added a small amount &mdash; just 1 percent by weight &mdash; of an inexpensive compound called urea to their mixture. In TEM images of the particles formed, the &ldquo;undesirable nanoparticles were largely gone,&rdquo; says Deng.Experiments in the laboratory coin cells showed that the addition of urea significantly altered the response to changes in the annealing temperature. When the urea was absent, raising the annealing temperature led to a dramatic decline in performance of the cathode material that formed. But with the urea present, the performance of the material that formed was unaffected by any temperature change.That result meant that &mdash; as long as the urea was added with the other precursors &mdash; they could push up the temperature, shrink the annealing time, and omit the gradual ramp-up and cool-down process. Further imaging studies confirmed that their approach yields the desired crystal structure and the homogeneous elemental distribution of the cobalt, nickel, manganese, and lithium within the particles. Moreover, in tests of various performance measures, their materials did as well as materials produced by coprecipitation or by other methods using long-time heat treatment. Indeed, the performance was comparable to that of commercial batteries with cathodes made of NCM811.So now the long and expensive second stage required in standard coprecipitation could be replaced by just 20 minutes of annealing at about 870 C plus 20 minutes of cooling down at room temperature.<h2>Theory, continuing work, and planning for scale-up</h2>While experimental evidence supports their approach, Deng and her group are now working to understand why it works. &ldquo;Getting the underlying physics right will help us design the process to control the morphology and to scale up the process,&rdquo; says Deng. And they have a hypothesis for why the lithium nanoparticles in their flame synthesis process end up on the surfaces of the larger particles &mdash; and why the presence of urea solves that problem.According to their theory, without the added urea, the metal and lithium atoms are initially well-mixed within the droplet. But as heating progresses, the lithium diffuses to the surface and ends up as nanoparticles attached to the solidified particle. As a result, a long annealing process is needed to move the lithium in among the other atoms.When the urea is present, it starts out mixed with the lithium and other atoms inside the droplet. As temperatures rise, the urea decomposes, forming bubbles. As heating progresses, the bubbles burst, increasing circulation, which keeps the lithium from diffusing to the surface. The lithium ends up uniformly distributed, so the final heat treatment can be very short.The researchers are now designing a system to suspend a droplet of their mixture so they can observe the circulation inside it, with and without the urea present. They&rsquo;re also developing experiments to examine how droplets vaporize, employing tools and methods they have used in the past to study how hydrocarbons vaporize inside internal combustion engines.They also have ideas about how to streamline and scale up their process. In coprecipitation, the first stage takes 10 to 20 hours, so one batch at a time moves on to the second stage to be annealed. In contrast, the novel FASP process generates particles in 20 minutes or less &mdash; a rate that&rsquo;s consistent with continuous processing. In their design for an &ldquo;integrated synthesis system,&rdquo; the particles coming out of the baghouse are deposited on a belt that carries them for 10 or 20 minutes through a furnace. A deagglomerator then breaks any attached particles apart, and the cathode powder emerges, ready to be fabricated into a high-performance cathode for a lithium-ion battery. The cathode powders for high-performance lithium-ion batteries would thus be manufactured at unprecedented speed, low cost, and low energy use.Deng notes that every component in their integrated system is already used in industry, generally at a large scale and high flow-through rate. &ldquo;That&rsquo;s why we see great potential for our technology to be commercialized and scaled up,&rdquo; she says. &ldquo;Where our expertise comes into play is in designing the combustion chamber to control the temperature and heating rate so as to produce particles with the desired morphology.&rdquo; And while a detailed economic analysis has yet to be performed, it seems clear that their technique will be faster, the equipment simpler, and the energy use lower than other methods of manufacturing cathode materials for lithium-ion batteries &mdash; potentially a major contribution to the ongoing energy transition.This research was supported by the MIT Department of Mechanical Engineering.This article appears in the&nbsp;<a href="https://energy.mit.edu/energy-futures/winter-2023/" target="_blank">Winter 2023</a>&nbsp;issue of&nbsp;Energy Futures, the magazine of the MIT Energy Initiative.<hr>&quot;Reprinted with permission of&nbsp;<a href="https://news.mit.edu/2023/using-combustion-make-better-batteries-0216" id="isPasted" rel="noopener noreferrer" target="_blank">MIT News</a>&quot; &nbsp;

Left to right: Graduate student Chuwei Zhang, Assistant Professor Sili Deng, graduate student Maanasa Bhat, and postdoc Jianan Zhang stand behind the lab-scale apparatus they use to investigate a low-cost method of synthesizing materials critical for manufacturing lithium-ion batteries. Photo: Gretchen Ertl

An MIT team is working to harness combustion to yield valuable materials, including some that are critical in the manufacture of lithium-ion batteries.

Using combustion to make better batteries

Cables that enable&hellip;kind of cheesy right? But, it&rsquo;s what we do. We provide an external solution that makes batteries perform better, and we do it with a cable.<h3>Do batteries really need to be better?</h3>Here&rsquo;s the truth: batteries alone can&rsquo;t power our future. What they can do and what they should do are not the same. Although they can store energy for long durations (high specific energy) and have a low self-discharge, they have a hard time delivering a lot of energy very quickly (low specific power) and have a relatively short operating life. Charging or discharging at high rates is damaging to batteries, resulting in frequent and costly replacements. The current way around this is to oversize the battery so the system can handle these high charge/discharge rates, but this is expensive and unsustainable for the renewables industry.<h3>If batteries alone can&rsquo;t do it, then what do we do?</h3>Batteries aren&rsquo;t the only energy storage technology out there, and it&rsquo;s time to start bringing the others onto the playing field. One of these other technologies is supercapacitors. Supercapacitors have a long operating life (upwards of one million cycles) and deliver a lot of energy very quickly (high specific power), making them the perfect solution for applications that require bursts of high power. However, supercapacitors lack the high specific energy and low self-discharge rate that batteries have, making it difficult to replace batteries with supercapacitors in some applications.But what if what we&rsquo;re looking for isn&rsquo;t necessarily a replacement but an addition? The ideal energy storage system would utilize multiple technologies to get the best of both (or all) worlds, creating a hybrid energy storage system. It&rsquo;s easier said than done, however. Combining multiple technologies does not come without tradeoffs. Most applications are limited in physical space, forcing designers to sacrifice specific energy for specific power or vice versa. This tradeoff typically discourages the usage of hybrid systems, but what if something on the market could mitigate these tradeoffs?<h3>Capacitech&rsquo;s power storing cables are the answer</h3>Capacitech&rsquo;s cables leverage the characteristics of supercapacitors to enhance energy-dense technologies like batteries and fuel cells without the tradeoffs that typically come with hybrid energy storage systems. We hide supercapacitor technologies in the wiring infrastructure, keeping areas aesthetically pleasing and allowing customers to utilize traditionally unused space for energy storage. As a supercapacitor would, our cables provide peak power support, helping batteries start loads they may not have been able to do on their own.Electronics designed to manage the power flow through the system are pre-integrated into the cables, allowing the battery and our cable to pass the work off to one another during situations such as power surges or periods of steady-state operation. These electronics, paired with our cable being battery and inverter agnostic, enable a drop-in and easy installation. Simple installations allow customers to enhance pre-existing battery systems without costly redesigns, reducing one-time and ongoing operating expenses.&nbsp;Capacitech bridges the gap between energy storage technologies, enhancing and enabling hybrid systems. Our cables provide the advantages of supercapacitors to create the ideal energy storage system, all while mitigating the tradeoffs typical of them.

Batteries alone can’t power our future. However, finding a viable battery replacement can prove to be a difficult task. Perhaps the answer is an addition to batteries instead of trying to replace them.