Fast-Charging Li Battery Could Make ‘Range Anxiety’ a Thing of the Past

Andrew Corselli

A team at Cornell University created a new lithium battery that can charge in under five minutes — faster than any such battery on the market — 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 Professor and Team Lead Lynden Archer. “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.”

Below is an exclusive Tech Briefs interview — edited for length and clarity — with Professor Lynden Archer and doctoral student Shuo Jin.

Tech Briefs: What was the biggest technical challenge you faced while developing this fast-charging lithium battery?

Archer/Jin: Of course, behind any successful research project there are often countless failures, but also years of research experience and an accumulation of knowledge about how to address these failures. This research reported in our recent article builds on Archer group's prior expertise in stabilizing anodes (such as Zn, Al, and Li), typically under more moderate current density conditions. Indeed, in prior studies by the group, Indium was explored as an interphase-forming material to support charging of Li-metal anodes.

These studies employed a joint-density functional theoretical approach to show that Indium has unusually fast surface mobility for Li and they performed electrochemical experiments to verify the predictions. However, fast-charging of the resulting Li-metal anodes was unsuccessful because the focus was on Li plating on a Cu metal substrate protected by the In interphase during battery charging.

The key breakthrough in the current work resulted from detailed atomistic calculations and painstaking experiments aimed at understanding the movement of Li ions in bulk Indium metal. The most important finding was that Li-ions moved unusually quickly both on the surface of the In and in the bulk material. This discovery means that an entire battery electrode can be formed using In and that electrode can be used as the basis for fast-charge Li-ion battery cells. When such a cell is charged quickly, Lithium alloys with In, rather than plating the metal, which leads to both very high charging rates and anode reversibility.

Tech Briefs: Can you explain in simple terms how everything works?

Archer/Jin: In our study, we replaced the conventional graphite anode used in present-day Li-ion batteries with a new material, indium (In). When one charges any of today’s Li-ion batteries, Li ions intercalate between carbon layers in the graphite anode. The rate at which a desired amount of Li can be inserted into the graphite determines how fast the battery can be charged. This rate is in turn controlled by how fast any single Li-ion can move in the in the interlayer space (i.e., the solid-state migration rate).

Our research revealed that graphite anodes are unable to function effectively at the high current densities necessary for fast-charging batteries because the migration rates are slow. Replacing the graphite anode with Indium changes all of this because it leads firstl, to much, much faster (approximately 20 times faster) Li-ion migration speeds in the battery anode.

Second, once the Li ions enter an Indium anode, they remain free to diffuse around before being frozen in place by the alloying reaction on timescales that are two to three orders of magnitude longer than in the corresponding graphite anode. The two improvements (much faster migration and much slower trapping of Li-ions) act synergistically to allow the anode to be charged very quickly while maintaining a near equilibrium distribution in the In anode, which is a requirement for good reversibility.

Tech Briefs: What are the pros and cons of this battery technology?

Archer/Jin: The main advantage is undoubtedly fast charging and relatively stable charge-discharge cycling behavior when a fast-charge, slow-discharge protocol is used. For example, our indium anode materials can fully charge In/LFP batteries in just five minutes, and in some cases even as little as two minutes, and maintain such high levels of charge over 100 charge-discharge cycles. This can be compared with today’s state-of-the-art Li-ion technology where a 30-minute charge is among the fastest reported and, even then, the battery typically only charges to 80 percent or so of its full capacity.

Li-ion batteries based on Indium presently have two main drawbacks. First, the atomic mass of indium is high (114.82 g/mol), approximately 60 percent higher than the relative atomic mass of the C₆ species that host Li in present day Li-ion batteries. It means that to achieve a storage capacity in a fast-charge battery based on In, compared to a state-of-the-art Li-ion battery that uses a graphitic carbon anode, the anode would need to be 60 percent heavier.

The second drawback is that Indium is not abundant in the earth’s crust (approximately 50 parts per billion, similar to silver). It is also typically extracted as a secondary product from zinc-mining operations, which means that the material costs are high and dependent on the demand for zinc.

Tech Briefs: Do you have any plans for further research?

Archer/Jin: A key benefit of our work with Indium is that it has revealed the design rules for creating truly fast-charging batteries. As discussed in the published paper, these benefits are preserved to an extent in anodes formed by blending In with its much lighter weight and less expensive cousin aluminum to create In-Al anodes. There are other exciting options along these lines that guide our current work, which are aimed at preserving the exceptional attributes of In for lighter-weight, lower-cost alloy anodes.

Tech Briefs: Do you have any advice for engineers/researchers aiming to bring their ideas to fruition?

Archer/Jin: The materials chemistry space available for battery electrode design is quite vast. Indeed, even with typical constraints of cost, weight, and manufacturability, the range of options is far too great for meaningful progress by Edisonian, trial-and-error experiment designs. We see significant value in combining predictions from theoretical and computational models, even of simplified systems, with experiments to converge more quickly on the breakthroughs we need.

Likewise, we would encourage investigators working in the field to become as comfortable in reporting failures (e.g., what did not work and why; under what conditions might a successful material cease to be advantageous), as they are with reporting successes.

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