One step hot-pressing method for hybrid Li metal anode of solid-state lithium metal batteries

Abstract

Safety issues induced by infinite anode volume change and uncontrolled lithium (Li) dendrite growth have become the biggest obstacle to the practical application of Li metal batteries. In addition, the traditional rolling method makes it difficult to manufacture thin Li foil with high mechanical strength and low Li content. Herein, a three-dimensional (3D) lithophilic carbon paper/copper (Cu) current collector hybrid anode with ultra-low Li metal content is prepared by a hot-pressing method. The highly reversible and stable lithiophilic layer LiCx formed in situ by heating/pressing treatment provides abundant nucleation sites and reduces the Li nucleation overpotential, thereby effectively suppressing Li dendrite growth. Moreover, the volume change and pulverization problems of Li metal anode during deposition/stripping also can be accommodated by the 3D skeleton. The optimization effect has been directly confirmed by in-situ optical and ex-situ scanning electron microscope observation. Therefore, highly stable performance (158.4 mA h g−1 at 2 C after 200 cycles with a capacity retention of 95.24%) in Li@LCP-Cu||NCM811 coin cell can be achieved. Furthermore, the solid-state battery assembled with the hybrid anode, poly(vinylidene fluoride) (PVDF)-based polymer electrolyte and polyethylene oxide (PEO) interface functional layer also exhibits the best electrochemical and safety performance, which also proves that the Li@LCP-Cu anode has great potential for application in solid-state batteries.