Realizing an Applicable 'Solid -> Solid' Cathode Process via a Transplantable Solid Electrolyte Interface for Lithium-Sulfur Batteries

摘要

The conventional lithium-sulfur battery (LSB) undergoes a "solid-liquid-solid" cathode process during which the intermediate polysulfides dissolve into the electrolyte, leading to a serious "shuttle" reaction and significantly shortened lifespan. Here, we realize a novel "solid -> solid" cathode mode for LSBs via a transplantable solid electrolyte interface (SEI). The SEI is in situ formed in a carbonate-based electrolyte with high-concentration dualsalt during the initial discharge process. The solid -> solid cathode process does not involve any dissolution of the intermediates; hence, the "shuttle effect" can be totally eliminated. Furthermore, the SEI shows a high electrolyte compatibility and can be transplanted to the conventional carbonate-based/ether-based electrolytes. The sulfur/carbon composite with 65% sulfur a reversible specific capacity of 1009 mA h g(-1) and negligible self-discharge. The SEI strategy can successfully break the limitation from the traditional "catholyte" electrode mechanism. Meanwhile, it provides large flexibility for designing high-loading carbon hosts and selecting an electrolyte for high-performance LSBs.