Electrolyte Depletion Triggers Vicious Circles in Fast-Charging Batteries

Abstract

Abstract Fast-charging lithium-ion batteries provide a promising solution to addressing the range anxiety of electric vehicles (EVs) but they face challenges in durability and safety. Kinetically driven lithium-plating on the anode is widely considered as a major bottleneck and has dominated the research attention so far. Here we study fast-charging-induced failures in EV-relevant batteries through lengthscale-bridging, multi-modal correlative imaging techniques. Electrolyte depletion is found to be the first domino to fall, which triggers a wide range of anode failures including the lithium plating and byproducts accumulation. The cathode remains relatively health early on but does exhibit increasing heterogeneity in lithium concentration, particle fracture behaviors, and lattice-structure disorder at the late-stage. These complex electro-chemo-mechanical interplays trigger self-amplifying “vicious circles” and cause severe electrode distortion and even rupture inside the batteries, which become hidden safety threats. This work provides the much-needed, holistic perspectives to developing better fast-charging batteries.