A Polymeric/inorganic Composite Coatings on the Separator for High-energy Lithium Metal Battery

Lithium metal (Li) is a highly promising anode for next-generation rechargeable batteries. However, the development of rechargeable lithium metal batteries is hampered by the issues such as low Coulombic efficiency, unstable growth of the solid-electrolyte interphase (SEI) and dendrites. Herein, a polymeric inorganic composite coatings (PICC) on the Celgard separator has been developed to regulate the Li-ion transport during charge/discharge of the battery. The PICC is a combination of poly(vinylidene fluoride) (PVDF) and Li6.03La3ZrNb0.25Al0.24O12 (LLZO). In the carbonate-based electrolyte, the cycle life of Li ‖ Cu batteries with coating (PVDF:LLZO=1:2) increases from 30 cycles for uncoated batteries to 120 cycles and a high Coulomb Efficiency of 96% is achieved. Moreover, the Li‖NCM811 batteries using the PICC exhibit decent rate and cycling performance. After 100 cycles, the capacity retention of 94% at 0.2C is obtained, and the specific capacity is maintained above 191 mAh/g.