Surface-patterned graphite electrode with hybrid polymer/garnet electrolyte for all-solid-state batteries

Abstract

Graphite remains an anode candidate for all-solid-state batteries (ASSBs) in order to fundamentally avoid the risks of lithium metal in secondary batteries. However, due to the low specific capacity of graphite, its thickness inevitably increases beyond that in lithium-ion battery to achieve a much higher areal capacity in ASSBs. The current study aimed to present a surface-patterned graphite electrode with solid-state hybrid electrolyte, a composite of poly(ethylene oxide) and Li7La3Zr2O12, which is mechanically soft enough to be deformed readily. Following simple mechanical imprinting processes, the all-solid-state graphite electrode achieved enhanced adhesion property, which contributed to the suppression of electrode delamination during long-term cycling. Moreover, it offered short diffusion pathway for rapid ion transportation, thereby allowing the delivery of higher specific capacity (291 mAh/g) than the control (<247 mAh/g) even under thick-electrode conditions. Especially, the patterns on all-solid-state graphite electrodes resulted in lower and stable overpotentials as well as longer cycle life. Hence, surface patterning could be a simple yet impactful method to revisit reliable graphite electrodes for ASSBs.