Tongchao Liu

Tongchao Liu, 32, has developed lithium batteries that can be recharged more times than their predecessors and cost less to build. Since battery life and cost are major obstacles to electric mobility, his work could go a long way toward ensuring broader acceptance of electric vehicles.

Improving battery cycle life—the number of times you can charge and discharge a battery before it stops working—is a major challenge. Surprisingly, researchers haven’t been able to agree on what causes batteries to eventually fail.

Liu, an assistant chemist at Argonne National Laboratory in the US, answered the question by building a new diagnostic system. The system unified multiple theories by determining that most failures in lithium batteries take place at the cathode—the electrode where current flows out of a battery—and result from physical strain as internal parts of the cathode expand and contract during each charge and discharge cycle.

Next, Liu invented a new cathode structure, using a material called a perovskite, that’s better able to withstand the strain. This innovation tripled the life of the batteries he worked on, reduced the cost to build them by about 25%, and eliminated the need to use cobalt. Widely used in existing lithium batteries, cobalt is mined primarily in the Democratic Republic of Congo and Russia, where workers are exploited and environmental costs are considerable.

Liu’s breakthrough has gained the interest of commercial businesses, which are particularly interested in reducing the use of cobalt. But his longer-term ambitions include eliminating the need for other problematic elements like nickel—and inventing entirely new battery chemistries that are immune to physical strain in the first place.