Surface Coating on a Separator with a Reductive Solid Li-Ion Conductor for Dendrite-Free Li-Metal Batteries
Bing Huang, Jiangbin Luo, Biyi Xu, Zhihong Li, Yutao Li, Yong Che, Chang‐An Wang
Abstract
The poor mechanical strength of the polymer separator and the uneven deposition of Li ions during the stripping/plating process in the lithium-metal batteries have severely deteriorated the electrochemical performance and safety of lithium batteries. Herein, a polydopamine-modified polypropylene (PP) separator with a coating layer of 1.5 μm thickness of polydopamine-modified perovskite Li-ion solid electrolyte Li3/8Sr3/8Ta3/4Zr1/4O3 (LSTZ) nanopowders is proposed, which can effectively promote the Li+/electron transfer and physical performance during the discharge/charge process in lithium-metal batteries. The LSTZ-decorated PP separators provide an improved wettability of the liquid electrolyte and excellent Li+/electron balance at the separator/lithium-metal interfaces, leading to higher Coulombic efficiencies and enhanced cycling stabilities in both Li/LSTZ-coated PP/Cu and Li/ LSTZ-coated PP/Li cells. As a result, the Li/LSTZ-coated PP/LiFePO4 cells have a capacity retention rate of 90% after 600 cycles and a Coulombic efficiency of 93.3%.