Nitrogen, sulfur Co-doped carbon nanosheets embedded with CoS/Co9S8 composite for high-stability lithium storage

Metal sulfides have emerged as eminent candidates for anodes in lithium-ion batteries because of their low cost and high theoretical capacity. Nevertheless, their Li storage performance is hindered by their inherent low conductivity and dramatic volume changes. To exceed this limitation, in this study, we synthesized a composite material comprising heterostructured CoS/Co9S8 grains incorporated into N, S co-doped carbon (labeled as CSCSC-800) through a solid-state pyrolysis reaction. The N, S co-doped carbon matrix could boost electrical conductivity and protect cobalt sulfides from volume changes. Furthermore, the heterostructured CoS/Co9S8 possesses abundant electrochemical active sites owing to its ubiquitous crystal boundary between the CoS and Co9S8 grains. Benefiting from the synergy of the two components, CSCS-C-800 displayed a satisfactory cycling lifespan, achieving remarkable capacity retention of 90% and low capacity fading per cycle of 0.025% during 400 successive cycles at 0.5 A g(-1). We believe that these outcomes obtained herein will be helpful in obtaining advanced metal sulfide-based materials for applications in electrochemical charge storage systems.

Automated summary

In this study, a composite material combining heterostructured CoS/Co9S8 grains with N, S co-doped carbon was synthesized to address the limitations of low conductivity and volume changes in metal sulfides for lithium-ion battery anodes. The synergistic effects of the two components led to satisfactory cycling performance, with CSCS-C-800 demonstrating remarkable capacity retention and low capacity fading over 400 cycles. These outcomes pave the way for advanced metal sulfide-based materials in electrochemical charge storage applications.