Li2S@NC composite enable high active material loading and high Li2S utilization for all-solid-state lithium sulfur batteries

Abstract

All-solid-state Li–S batteries (ASSLSBs) offer an opportunity to realize both high energy density, safety and reliability, via eliminating the polysulfides shuttle effect and flammable liquid electrolyte. However, the sluggish kinetics of S and Li2S solid conversion results in low discharge capacity at high active material loading, which is critical for ASSLSBs to implement the high energy density potential. Herein, nitrogen doped-carbon (NC) coated Li2S (Li2S@NC composite) is developed for ASSLSBs that highly improves electrochemical performance. A thin and uniform nitrogen doped-carbon layer is coated on Li2S via pyrolysis deposition approach to prepare Li2S@NC. The as obtained Li2S@NC composite exhibits greatly enhanced electrochemical performance with high reversible capacity, high coulombic efficiency of ~100%, good rate capability and cycling stability. Particularly, outstanding electrochemical performance with high capacity of 931 mAh g−1 can also be obtained at both high Li2S content (43%) and high areal Li2S loading (10.4 mg cm−2).