3D Net-like GO-d-Ti3C2Tx MXene Aerogels with Catalysis/Adsorption Dual Effects for High-Performance Lithium-Sulfur Batteries.

Abstract

High theoretical specific capacity and rich resources in nature make sulfur an ideal cathode material for lithium-metal batteries. However, the shuttle effect and sluggish reduction reaction kinetics of lithium polysulfides (LiPSs) seriously affect the performance of the batteries. Here, we report GO-d-Ti3C2Tx MXene aerogels with a novel three-dimensional (3D) reticular structure that served as sulfur host cathode materials for lithium-sulfur batteries (LiSBs), which benefits adsorption/catalytic conversion of LiPSs simultaneously. The dissolved LiPSs can be rapidly captured through chemisorption and then catalyzed into insoluble Li2S by low-coordinated-state Ti on the d-Ti3C2Tx MXene surface. The combination of adsorption and catalysis enormously improves the capacity and cycling performance of LiSBs. At an S mass loading of 1.5 mg cm-2, the cell with the S@GM0.4 composite electrode achieves excellent cycling performance. The discharge specific capacity of 1039 mA h g-1 (1.56 mA h cm-2) decays to 542.9 mA h g-1 after 1000 cycles with a capacity fading rate of 0.048% per cycle at 0.5 C. Even at an S mass loading of 4.88 mg cm-2, an areal capacity of 4.3 mA h cm-2 can be achieved at 0.2 C.