Fabrication of N, S co-doped carbon nanofiber matrix with cobalt sulfide nanoparticles enhancing lithium/sodium storage performance

•The carbon nanofiber coated cobalt sulfide nanoparticles with high N, S doping content could be synthesized with N2 and CS2 assistance.•N, S co-doped carbon reduces the diffusion barrier and enhances the adsorption of Li/Na ions.•The sample exhibits excellent reversible capacity for lithium/sodium storage.