CuS quantum dot modified carbon aerogel as an immobilizer for lithium polysulfides for high-performance lithium–sulfur batteries

Abstract

CuS quantum dot (QD) modified carbon aerogels were successfully prepared via a facile and scalable method to encapsulate sulfur and polysulfides into the hierarchical porous channel of lithium–sulfur batteries. The surface morphologies and microstructures of the CuS QD modified composites and their electrochemical performances are investigated in detail. The modified 3D interconnected porous CA with excellent conductivity and high specific surface can effectively facilitate electron and ion transfer. The well-distributed CuS QDs further provide abundant active adsorption sites to anchor sulfur particles and polysulfides. As a result of the synergistic effect of CuS QD and hierarchical mesoporous carbon, the composite delivers a high initial capacity of 1318 mA h g⁻¹ at a current rate of 0.2C and retains 1073 mA h g⁻¹ after 100 cycles. Furthermore, the high conductive CuS QD modified composite provides a stabilized capacity of over 840 mA h g⁻¹ for over 500 cycles with only 0.05% decay per cycle at 0.5C.