The beneficial effects of black phosphorous modification of the anode current collector in Li-metal free Li2S-based batteries

Li-S batteries assembled without a lithium metal anode can significantly increase the battery specific energy and obviate the safety issue of excess Li metal in the battery. In this study we found that a black phosphorous (BP) modified cooper foil current collector could provide a beneficial anode solid-electrolyte-interface (SEI) to enable the charging and discharging of Li-metal free Li 2 S-based batteries at higher C rates. The BP modification is effective in several aspects: the lithiophilicity of BP reduces the energy barrier in Li metal deposition and stripping during battery charge and discharge. The reactions between BP and lithium polysulfides also form Li 7 PS 6 in the anode SEI layer. Since Li 7 PS 6 has a high ionic conductivity for Li + diffusion, the Li plating/stripping efficiency is improved. The synergy of the lithiophilicity of BP and a Li 7 PS 6 -rich anode interphase layer was demonstrated in Li-metal free Li 2 S batteries, where the capacity retention over 100 cycles is 64.8% at the 0.2 C rate. The findings here show that current collector modifications should attend to multiple functionalities in order to be effective for the Li-metal free Li 2 S batteries. Schematic of Li plating and stripping on Cu and BP@Cu current collectors. • A binder-free BP modified copper foil (BP@Cu) current collectors was used as the anode of Li-metal free Li 2 S batteries. . • The synergy of the lithiophilicity of BP and a Li 7 PS 6 -rich anode interphase layer facilitate reversible Li plating and stripping. . • The BP@Cu .|| Li 2 S full cell shows an impressive capacity retention over 100 cycles at practical current rates.