Air-stable dopamine-treated garnet ceramic particles for high-performance composite electrolytes

Garnet-type Li7La3Zr2O12 (LLZO) solid-state electrolytes have shown the promise in the fabrication of solid lithium batteries with high energy density and safety. However, they are unstable against the air exposure and Li2CO3 forms on the surfaces, which is detrimental to the ionic conduction and the electrochemical stability of LLZO. Herein, the Li2CO3 layers on the LLZO surfaces are transformed into the air-stable shell via the chemical treatment of dopamine at room temperature, which enables the lipophilic property of LLZO fillers. The dopamine-based shells on LLZO particles can resist the air attack for up to 20 days. The improved ionic conductivity, electrochemical, and cycling stability are achieved for composite electrolytes with the above Li2CO3-free LLZO particles. These results present a facile solution for the functionalization of LLZO ceramic fillers with high performances and pave the way for the scalable production of LLZO-based solid lithium batteries.