A WS2/Co9S8 heterostructure with a carbon layer anchored in nitrogen-doped graphene foam as an anode for boosting lithium storage

Abstract

In this work, globular WS₂/Co₉S₈ nanoflowers coated with nitrogen-doped carbon (NC) and anchored on nitrogen-doped porous graphene (NPG) foam (NPG@WS₂/Co₉S₈@NC) were successfully fabricated via solvothermal and chemical vapor deposition methods. The WS₂/Co₉S₈ heterostructure has the ability to generate an internal electric field that acts as a powerful driving factor for charge transport. The NC layer and three-dimensional NPG foam provide a special structure for the stabilization of WS₂ nanosheets and Co₉S₈ nanoparticles, which not only increases its conductivity and expands the layer spacing, but also mitigates structural changes in electrode materials during charge and discharge. When NPG@WS₂/Co₉S₈@NC is treated as the anode in a lithium-ion battery (LIB), a capacity of 952 mA h g⁻¹ at 1 A g⁻¹ can be achieved even after 600 cycles. The combined effect of self-supported electrodes and heterostructures has given us some new opportunities for improving the capability of anode components in LIBs.