Stabilizing Lithium Metal Anodes by a Self-Healable and Li-Regulating Interlayer

Abstract

Lithium (Li) metal is a promising anode for high-energy-density batteries, but its practical applications are severely hindered by side reactions and dendrite growth at the electrode/electrolyte interfaces. Herein, we propose that the problems can be effectively solved by introducing an interlayer. The interlayer is composed of a trifluorophenyl-modified poly(ethylene imine) network cross-linked by dynamic imine bonding (PEI-3F). The trifluorophenyl moieties of the interlayer can coordinate with Li+, which enables the interlayer to adjust the distribution of Li+ at the electrode/electrolyte interface, while the imine bonding endows the interlayer with self-healing capability. The resulting Li anodes exhibit excellent cycling stability (250 cycles in asymmetric Li||Cu cells) and dendrite-free morphologies. A lithium sulfur (Li-S) cell that uses anodes shows a retention rate of 91% after 100 cycles with a high sulfur loading (5 mg cm-2). This study provides a novel strategy to concern the intrinsic drawbacks of a lithium metal anode, which can be extended to other light-metal electrodes aiming for high energy-density batteries.