Sodium EV battery beats lithium in charging speed, heat control

Researchers at Tokyo University of Science have experimentally demonstrated that sodium-ion batteries (SIBs) exhibit intrinsically faster charging speeds than conventional lithium-ion batteries (LIBs), particularly when using hard carbon (HC) anodes. This porous, low-crystalline carbon material facilitates rapid sodium ion insertion, enabling SIBs to achieve energy densities comparable to LIBs. The study addresses a key limitation in traditional testing methods, which often underestimate HC’s charging capabilities due to ion transport bottlenecks in dense electrodes. By employing a “diluted electrode method” that isolates HC particles with inactive aluminum oxide powder, the researchers accurately measured ion diffusion rates and found sodium ions diffuse faster than lithium ions within HC. The team identified the rate-limiting step in charging as the “pore-filling” process, where ions form pseudo-metallic clusters inside HC nanopores. Sodium requires less activation energy than lithium for this clustering, resulting in faster kinetics and reduced sensitivity to temperature changes. These findings suggest that SIB