I had dinner last night with a neighbor who asked me why sales of electric cars in America appear to be slowing. He was referring specifically to the decision by Ford to lower its production plans for the F-150 Lightning electric pickup truck. That conversation clarified several things for me. One, the charging infrastructure in America is inadequate for the needs of many drivers. Two, the batteries available today simply don’t charge fast enough or deliver enough range to suit mainstream drivers.
Batteries are the issue and, as we have said on more than one occasion, the batteries that will power our electric vehicles in the future have not been invented yet. When they are, the affect on the market for electric vehicles will be similar to how the self starter and the automatic transmission made the automobile accessible to many more drivers. Scientists at Cornell and Harvard may be inventing those improved batteries as we speak.
Cornell Developing Fast Charging Batteries
A team at Cornell Engineering has created a new lithium battery that can charge in under five minutes while maintaining stable performance over extended cycles of charging and discharging. The breakthrough could alleviate “range anxiety” among drivers who worry electric vehicles cannot travel long distances without a time consuming recharge.
“Range anxiety is a greater barrier to electrification in transportation than any of the other barriers, like cost and capability of batteries, and we have identified a pathway to eliminate it using rational electrode designs,” said Lynden Archer, the dean of Cornell Engineering, who oversaw the project. “If you can charge an EV battery in five minutes, I mean, gosh, you don’t need to have a battery that’s big enough for a 300 mile range. You can settle for less, which could reduce the cost of EVs, enabling wider adoption.”
After fast charging their new lithium battery, the researchers observed its indium anode had a smooth lithium electrodeposition, whereas other anode materials can grow dendrites that impact the battery’s performance. The team’s research paper entitled “Fast-Charge, Long-Duration Storage in Lithium Batteries,” was published January 16 in the journal Joule. The lead author is Shuo Jin, a doctoral student in chemical and bio-molecular engineering.
“Our goal was to create battery electrode designs that charge and discharge in ways that align with daily routine,” Jin said. “In practical terms, we desire our electronic devices to charge quickly and operate for extended periods. To achieve this, we have identified a unique indium anode material that can be effectively paired with various cathode materials to create a battery that charges rapidly and discharges slowly.”
The Cornell researchers focused on Damköhler numbers — the measure of the rate at which chemical reactions occur relative to the rate at which material is transported to the reaction site. Identifying battery electrode materials with fast solid state transport rates helped the researchers pinpoint indium as an exceptionally promising material for fast charging batteries, primarily because it virtually eliminates the formation of dendrites.
“The key innovation is we’ve discovered a design principle that allows metal ions at a battery anode to freely move around, find the right configuration, and only then participate in the charge storage reaction,” Archer said. “The end result is that in every charging cycle, the electrode is in a stable morphological state. It is precisely what gives our new fast charging batteries the ability to repeatedly charge and discharge over thousands of cycles.”
Now, curb your enthusiasm, CleanTechies. Indium anodes aren’t perfect — or even practical. “While this result is exciting, in that it teaches us how to get to fast charge batteries, indium is heavy,” Archer said. “Therein lies an opportunity for computational chemistry modeling, perhaps using generative AI tools, to learn what lightweight materials chemistries might achieve the same intrinsically low Damköhler numbers.
“For example, are there metal alloys out there that we’ve never studied which have the desired characteristics? That is where my satisfaction comes from, that there’s a general principle at work that allows anyone to design a better battery anode that achieves faster charge rates than the state of the art technology.”
Translation: fast charging batteries from Cornell Engineering are a long way from being production ready, but the researcher have pried open a door. Can they capitalize on their discovery? Stay tuned.
Harvard Takes A Different Approach To Solid State Batteries
Researchers from the Harvard School of Engineering and Applied Sciences have developed a new lithium metal battery that can be charged and discharged at least 6,000 times — more than any other pouch battery cell — and can be recharged in a matter of minutes. As with the Cornell research, the focus at Harvard is on reducing or eliminating the formation of dendrites.
“Lithium metal anode batteries are considered the holy grail of batteries because they have ten times the capacity of commercial graphite anodes and could drastically increase the driving distance of electric vehicles,” said Xin Li, associate professor of materials science and senior author of the paper. “Our research is an important step toward more practical solid state batteries for industrial and commercial applications.”
In this new research, Li and his team stop dendrites from forming by using micron sized silicon particles in the anode to constrict the lithiation reaction and facilitate homogeneous plating of a thick layer of lithium metal. When lithium ions move from the cathode to the anode during charging, the lithiation reaction is constricted at the shallow surface and the ions attach to the surface of the silicon particle but don’t penetrate further. This is markedly different from the chemistry of liquid lithium ion batteries in which the lithium ions penetrate through deep lithiation reaction and ultimately destroy silicon particles in the anode.
“In our design, lithium metal gets wrapped around the silicon particle, like a hard chocolate shell around a hazelnut core in a chocolate truffle,” said Li. These coated particles create a homogenous surface across which the current density is evenly distributed, preventing the growth of dendrites. Because plating and stripping can happen quickly on an even surface, the battery can recharge in only about 10 minutes.
“Our research explains one possible underlying mechanism of the process and provides a pathway to identify new materials for battery design. Previous research had found that other materials, including silver, could serve as good materials at the anode for solid state batteries,” said Li. “Our research explains one possible underlying mechanism of the process and provides a pathway to identify new materials for battery design.”
Why do we do stories like this? Clearly, there is a huge gulf between research in the laboratory and commercial production. Here’s the answer. The EV revolution in America has hit the pause button. But better charging infrastructure is coming this year and next and new batteries that charge faster and deliver more range are just a laboratory breakthrough away.
People want to know they can rely on electric cars to take them where they need to when they need to go there — no excuses, no apologies, and no exceptions. It took 100 years to perfect the automobile. EVs have only been around in statistically significant quantities for about 13 years. This party has just begun. Keep calm and charge on.