KAIST simulation maps fast-charging damage in EV battery anodes

KAIST researchers used a three-dimensional model to simulate lithium-ion movement through a battery electrode. Their model, built from a commercial graphite anode, exposes how fast charging damages batteries in places that overall capacity figures can miss.

The team led by Professor Kang Taek Lee, in collaboration with Professor EunAe Cho, reconstructed the electrode’s graphite particles, binder and electrolyte-filled pores. The digital twin then simulated fast charging across different electrode thicknesses, porosities and binder layouts, mapping lithium-ion movement, lithium plating and internal mechanical stress.

The mechanism is small but consequential. When charging is too fast, some lithium ions cannot enter graphite particles quickly enough and form metallic deposits on the surface, a process called lithium plating. The protective solid electrolyte interphase, or SEI, can also become too thick or uneven, while swelling graphite particles press against surrounding materials and create stress.

The layout of the electrode mattered more than average figures suggested. In standard 50-micrometer anodes, binder placement changed total capacity by less than 4 percent, yet concentrating binder near the separator increased lithium plating near the current collector by over 10 percent compared with an even distribution. In 83 μm-thick anodes, strategic binder placement increased charge capacity by 18 percent over uneven distributions. Pore spaces also acted as buffers for expanding graphite particles.

So what, concretely? Battery makers could use the KAIST model to test where materials should sit before building physical prototypes, reducing reliance on trial and error when designing fast-charging cells. That could support longer-lasting EV batteries, but the figures come from simulations: no independent real-world test or production deployment is reported here.