Stable Plating and Stripping of Lithium Metal Anodes through Space Confinement and Stress Regulation.

Lithium metal anodes suffer from enormous mechanical stress derived from volume changes during electrochemical plating and stripping. The utilization of derived stress has the potential for the dendrite-free deposition and electrochemical reversibility of lithium metal. Here, we investigated the plating and stripping process of lithium metal held within a cellular three-dimensional graphene skeleton decorated with homogeneous Ag nanoparticles. Owing to appropriate reduction-splitting and electrostatic interaction of nitrogen dopants, the cellular skeletons show micron-level pores and superior elastic property. As lithium hosts, the cellular skeletons can physically confine the metal deposition and provide continuous volume-derived stress between Li and collectors, thus meliorating the stress-regulated Li morphology and improving the reversibility of Li metal anodes. Consequently, the symmetrical batteries exhibit a stable cycling performance with a span life of more than 1900 h. Full batteries (NCM811 as cathodes) achieve a reversible capacity of 181 mA h g at 0.5 C and a stable cycling performance of 300 cycles with a capacity retention of 83.5%. The meliorative behavior of lithium metal within the cellular skeletons suggests the advantage of a stress-regulating strategy, which could also be meaningful for other conversion electrodes with volume fluctuation.