Facile Assembly of 3D Porous Reduced Graphene Oxide/Ultrathin MnO2 Nanosheets-S Aerogels as Efficient Polysulfide Adsorption Sites for High-Performance Lithium–Sulfur Batteries

摘要

Rechargeable lithium–sulfur (Li–S) batteries are receiving much attention due to their high specific capacity, low cost, and environmental friendliness. Nonetheless, fast capacity decay and low specific capacity still limit their practical implementation. Herein, we report a facile strategy to overcome these challenges by the design and fabrication of 3D porous reduced graphene oxide/ultrathin MnO2 nanosheets- S aerogel (rGM-SA) composites for Li–S batteries. By a simple solvothermal reaction process, nanosized S atoms are homogeneously decorated into the 3D scaffold formed by reduced graphene oxide (rGO) and MnO2 nanosheets, which can form the homogeneous rGM-SA composites. In this porous network architecture, rGO serves as an electron and ion transfer pathway, a physical adsorption site for polysulfides, and provides structural stability. The ultrathin MnO2 nanosheets provide strong binding sites for trapping polysulfide intermediates. The 3D porous rGO/MnO2 architecture enables rapid ion transport and buffers volume expansion of sulfur during discharge. The rGM-SA composites can be directly used as lithium–sulfur battery cathodes without using binder and conductive additive. As a result of this multifunctional arrangement, the rGM-SA composites exhibit high and stable-specific capacities over 200 cycles and excellent highrate performances.