Hybrid Artificial Solid Electrolyte Interphase with Dendrite-Free Lithium Deposition and High Ion Transport Kinetics.

Interfacial issues and dendritic Li deposition in lithium metal batteries (LMBs) hamper the practical application of liquid or solid-state cells. Here, a hybrid solid electrolyte interphase (SEI), based on hydroxyl-functionalized boron nitride (BN) nanosheets and poly(vinyl alcohol), is designed to solve the unstable nature of the Li anode-electrolyte interface. Rather than acquiring a rich Li halide environment through intense electrolyte decomposition, the hybrid SEI effectively regulates electrolyte decomposition and guarantees uniform Li plating via boosting interfacial Li ion transport at the interface. The Li ion boosting kinetics were deeply analyzed using simulations and spectroscopic analysis. It is revealed that the hydroxyl-functionalized BN can decrease kinetic energy barriers for Li ions and strongly holds TFSI ions, thereby ensuring faster Li ion migration between electrodes and electrolytes. Tailoring the interfacial Li ion dynamics with hybrid SEI renders the Li transference number enhancement from 0.391 to 0.562 and 0.178 to 0.327 in liquid and solid-state cells, respectively. Moreover, Li symmetric cells with hybrid SEI exhibit an ultrahigh stability over 3500 h at 2 mA cm with 2 mA h cm, along with the improved solid-state LMB performances. Our results suggest increasing Li ion transport at the interface is an alternative to resolve Li anode issues.