Hierarchical nanoarchitecture of vanadium disulfide decorated 3D porous carbon skeleton with improved electrochemical performance toward Li ion battery and supercapacitor

Abstract

Vanadium disulfide (VS2) is deemed to be a competitive active material in electrochemical energy storage field in both lithium-ion battery and supercapacitor owing to its unique chemical and physical property. Nevertheless, serious aggregation and structure damage in continuous charge-discharges would result in a decreased capacity, an inferior cycling stability and a poor rate capability, which severly limits the practical application of VS2. In this current work, a hierarchical porous nanostructured composite composed of VS2 nanoparticles confined in gelatin-derived nitrogen-doped carbon network (VS2-NC) was successfully designed and synthesized via a simple freeze drying plus an annealing method. In this VS2-NC composite, porous architecture is conductive to providing high active surface areas, facilitating the access of electrolyte into active materials and ion diffusion. The confinement of carbon matrix on VS2 nanoparticles is beneficial to inhibition of the volume change, reinforcement of the structural stability and improvement of the overall electrical conductivity of composite. Benefitting from the advantages mentioned above, the as-prepared VS2-NC electrode demonstrates outstanding electrochemical performances. Employed as an anode for lithium ion battery, VS2-NC delivers a relatively high reversible capacity about ∼1061 mA h g−1 in 200-cycle test at 100 mA g−1. When applied in supercapacitor, VS2-NC electrode manifests a large pseudocapacitance of 407.3 F g−1 at a current density of 10 A g−1 and superior cycling stability.