PNNL

Abstract

We present a synergistic strategy to boost the cycling performance of Li-metal batteries. The strategy is based on the combined use of a micro-pattern (MP) on the surface of the Li-metal electrode and an advanced dual-salt electrolyte (DSE) system to more efficiently control undesired Li-metal deposition at higher current density (~3 mA cm-2). The MP-Li electrode induces spatially uniform current distribution to achieve dendrite-free Li-metal deposition beneath the surface layer formed by the DSE. The MP-Li/DSE combination exhibited excellent synergistic rate capability improvements that were neither observed with the MP-Li system nor for the bare Li/DSE system. The combination also resulted in the Li||LiMn2O4 battery attaining over 1,000 cycles, which is twice as long at the same capacity retention (80 %) compared with the control cells (MP-Li without DSE). We further demonstrated extremely fast charging at a rate of 15 C (19.5 mA cm-2).