Fabrication and lithium storage property of spherical-like Co1−xS@g-C3N4 microcomposite

Abstract A fluffy spherical Co1−xS@g-C3N4 microcomposite was synthesized via a facile one-step solvothermal method. In the resulting Co1−xS@g-C3N4 hybrid composite, Co1−xS nanoparticles are uniformly anchored onto the cotton-like g-C3N4 matrix. This spherical-like Co1−xS@g-C3N4 hybrid anode material delivers a higher reversible capacity of 789.59 mAh/g at a current density of 0.1 A/g than that of bare Co1−xS (22.02 mAh/g) after 210 cycles. Even at 1.6 A/g, it exhibits an ultra-long cycle life of 1000 cycles with a capacity of 487.93 mAh/g. The excellent electrochemical performances of Co1−xS@g-C3N4 are ascribed to its special fluffy structure and the uniform adherence of Co1−xS nanoparticles to g-C3N4 matrix, which not only afford abundant active sites and facilitate the transfer of electrons, but also alleviate the larger volume expansion of Co1−xS composite during charge/discharge processes. This synthetic strategy provides a simple and cost-effective avenue for ultra-long-life anode materials of lithium ion battery.