Amprius Announces 500 Watt-Hour per Kilogram Cell

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Amprius has announced a 500 Watt-hour per kilogram cell, essentially doubling the energy density available up to now.  Remember, though, that cell-levels of energy drop as the cells are incorporated into modules and packs, carrying the burdens of containment packaging, bus bars, and battery management systems (BMS) that lower total output.  Pack levels will be lower. Slow Progress This comes as the culmination of at least 14 year’s work, starting with Yi Cui’s work at Stanford University.  Your editor first saw him at a 2009 CAFE Foundation symposium at the Hiller Aviation Museum in San Carlos, California.  He was a proponent of the 10X battery, which at that time would have meant 10 times the energy storage of then typical cells, or around 10 times the 200 Watt-hours per kilogram then considered to be a respectable achievement. This blog reported in 2013, “According to Green Car Congress, ‘The company has also demonstrated greater than 650 and 700 Wh/L batteries with …

Group 14 Gets a Push from Porsche

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We covered Washington Governor Jay Inslee’s visit to the Group 14 Technologies battery plant in Woodinville last year.  Now the Group is getting attention from Porsche, among other funders.  The startup company announced raising $400 million from investors including the Teutonic automaker. According to Reuters, part of those funds will be used to build a second battery materials plant in eastern Washington State.  The company is now valued at over $1 billion, money which will help expand battery materials production for the silicon-lithium cell market. Silicon is a desirable material in batteries, capable of storing more energy than lithium or other metals.  It has a major drawback, though.  In expanding and contracting during charge-discharge cycles, it eventually deteriorates, crumbles, and brings the battery’s usefulness to an end. Dr. Yi Cui of Stanford University has tried various methods over the years to prevent such crumbling.  His firm, Amprius, has developed a silicon nanowire anode that enables a battery with 450 Watt-hour …

Cuberg Battery Flies 70 Percent Longer

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Cuberg’s recent test between their battery and a conventional lithium-ion battery resulted in the Cuberg battery keeping a drone flying 70-percent longer.  Given that the test is for two packs of equal weight, the result is an impressive one.  Cuberg’s co-founder and CEO has prepared for this success since his undergraduate days as a SURF (Summer Undergraduate Research Fellowship) Fellow, putting his summer vacations to good use.  He used the knowledge and experience he gained in three summer fellowships to help lead a dozen students “to design and develop innovative and efficient mechanical systems (including HVAC, hot water, insulation, appliances, and more) for the Solar Decathlon net-zero house competition.”  The team won first place in the hot water contest and second place in the engineering contest in the Decathlon.  Since then, he worked as an intern at Tesla Motors, using “physical, chemical, and electrochemical characterization techniques to study the degradation mechanisms of Li-ion batteries at the Cell Research Lab.”  This led …

Even with Batteries, Paul MacCready Was Right

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Dr. Paul MacCready repeatedly urged us to do more with less, getting big results from modest use of materials.  That philosophy may be upheld yet once again by researchers from the Helmholtz-Zentrum Berlin (HZB) Institute of Soft Matter and Functional Materials. As reported here many times, people like Dr. Yi Cui at Stanford University, researchers at MIT, the Fraunhoffer Institute in Germany and many others are attempting to find the magic combination of ingredients that will allow us to transcend the weight penalty we currently trade for payload in heavier-than-desired electric aircraft. Scientists at the HZB, led by  by Prof. Matthias Ballauff have directly observed for the first time a lithium-silicon half-cell during its charging and discharge cycles.  Dr. Beatrix-Kamelia Seidlhofero carried out the experiments using the neutron source located at the Institute Laue-Langevin in Grenoble, France.  She explains, “We were able to precisely track where the lithium ions adsorb in the silicon electrode using neutron reflectometry methods, and also …

Caging Silicon Anodes with Graphene

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Dr. Yi Cui of Stanford University has expanded the idea of “battery” to include conductive ink on paper, fruit-like clusters of energy-storing capsules, and now, nano-sized graphene cages in which the energy can romp like a hamster in a plastic ball.  He will be on hand at this year’s Sustainable Aviation Symposium on May 6, at the Sofitel San Francisco Bay hotel. His pioneering work with silicon as an electrode material goes back at least ten years, and has focused on overcoming silicon’s two major problems in battery use.  Silicon expands and begins breaking down during repeated charge-discharge cycles.  It reacts with battery electrolyte to form a coating that progressively destroys performance.  The combination of crumbling and coating finally makes the battery inoperable. His group at Stanford had found a way to “wrap every silicon anode particle in a custom-fit cage made of graphene, a pure form of carbon that is the thinnest and strongest material known and a great conductor …

Potassium Graphite Batteries?

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The greatest obstacle to discovery is not ignorance – it is the illusion of knowledge. Daniel J. Boorstin Oregon State University researchers in Corvallis, Oregon have worked around an intellectual roadblock they say has kept potassium from serious consideration as a battery material for over eight decades.  This could be good news, since potassium is more plentiful and lower cost than lithium, and according to OSU scientists, almost as energetic. Xiulei (David) Ji, the lead author of the study and an assistant professor of chemistry in the College of Science at Oregon State University. points out that potassium-ion batteries haven’t been considered since the Hoover administration. Ji said, “For decades, people have assumed that potassium couldn’t work with graphite or other bulk carbon anodes in a battery.  That assumption is incorrect.” Seeing around that conventional wisdom opens new alternatives to the lithium used in electrodes of lithium-ion batteries.  Even though Li is highly energetic, potassium comes close and may be …

EAS IX:  Materials Design for Battery Breakthroughs

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Dr. Yi Cui’s presentation title ended with, “from Fundamental Science to Commercialization,” an indication of the long, tough road that new developments are forced to take.  Considering that Sony introduced the Lithium battery as a commercial entity in 1991 (and that following at least an 18-year slog from laboratory to mass production), mostly incremental changes have come for the chemistry, echoing Dr. Cui’s pronouncement at EAS III that lithium batteries followed a “growth curve” of about eight percent per year, meaning that about every nine years, they should double in performance. Cui’s estimate has been borne out in reality, Nature magazine reporting in 2014, “Modern Li-ion batteries hold more than twice as much energy by weight as the first commercial versions sold by Sony in 1991 — and are ten times cheaper. But they are nearing their limit. Most researchers think that improvements to Li-ion cells can squeeze in at most 30% more energy by weight.” Cui spoke of attempting …

Aluminum Yolks and Titanium Shells

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A new “yolk-and-shell” nanoparticle could boost the capacity and power of lithium-ion batteries. MIT’s press release gives a graphic overview of what damages electrodes and shortens battery life.  “One big problem faced by electrodes in rechargeable batteries, as they go through repeated cycles of charging and discharging, is that they must expand and shrink during each cycle — sometimes doubling in volume, and then shrinking back. This can lead to repeated shedding and reformation of its “skin” layer that consumes lithium irreversibly, degrading the battery’s performance over time.” Dr. Yi Cui and teams at  Stanford’s National Accelerator Laboratory (Formerly the Stanford Linear Accelerator Center), and the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory all published papers on a similar  joint accomplishment three years ago, as reported in this blog.  Dr. Cui had studied several alternative ways to reduce the effects of expansion and contraction on electrodes. According to an MIT news release, “Now a team of researchers at MIT, led …

Samsung Almost Doubles Li-Ion Battery Capacity – in the Near Future

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Several sources report on Samsung’s announcement that they have developed a new technology that enables them to coat silicon battery cathodes with high crystal graphene, virtually doubling the capacity of lithium-ion batteries. Of course, Samsung relates this immediately to their popular smartphones and tablets, but the significance of this is not lost on electric vehicle designers.  Doubling the range of EVs “without adding a single pound of weight” would be a true game changer.  But don’t get excited too quickly. Silicon electrodes have been a major research effort for people like Dr. Yi Cui, who spoke at this year’s Electric Aircraft Symposium.  Issue surrounding their successful use have included silicon’s expansion when being charged and contraction when being discharged.  This errant flexibility causes eventual disintegration of the electrodes and shuts down the battery.  Attempts to use silicon nanowires still have led to embrittlement. Kompulsa.com reports Cho Jin-young from BusinessKorea explaining, “Currently, the development of high-capacity battery materials has been mostly done …

Dr. Yi Cui’s Latest, a Solid-state Electrolyte

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Green Car Congress reports that, “Stanford researchers led by Professor Yi Cui have used ceramic nanowire fillers to enhance the ionic conductivity of polymer-based solid electrolyte by three orders of magnitude. The ceramic-nanowire filled composite polymer electrolyte also shows an enlarged electrochemical stability window.” With solid-state batteries coming to the fore through efforts by Ann Marie Sastry at Sakti 3 and Qichao Hu at Solid Energy Systems, an improved solid electrolyte would seem to offer greater battery safety and stability “when compared with conventional liquid electrolytes. The abstract for the Stanford researchers’ paper in the journal ACS Nano Letters explains that “Currently, the low mobility of lithium ions in solid electrolytes limits their practical application. The ongoing research over the past few decades on dispersing of ceramic nanoparticles into polymer matrix has been proved effective to enhance ionic conductivity although it is challenging to form the efficiency networks of ionic conduction with nanoparticles. In this work, we first report that ceramic nanowire …