Tungsten disulfide nanoparticles embedded in gelatin-derived honeycomb-like nitrogen-doped carbon networks with reinforced electrochemical pseudocapacitance performance

Abstract

In this paper, we demonstrated a hierarchical honeycomb-like tungsten disulfide (WS2) composite nanostructure comprised of WS2 nanoparticles dispersed and embedded in gelatin-derived carbon networks with well-developed porous structures and high surface areas. In this composite, open porous architecture was favorable to easy access of electrolyte, efficient ion diffusion and relief of mechanical stress from volume variation. The unique inlaid configuration of WS2 nanoparticles in carbon matrix greatly inhibited aggregation of particles, improved structural stability and increased electrical conductivity. Profiting from these structural advantages, the optimized WS2 composite electrode demonstrated tremendously enhanced electrochemical properties. As an electrode material for pseudocapacitor, it exhibited a high capacitive value of 1305.5 Fg−1 under a current density of 0.2 A g−1. Even measured at 10 A g−1, the optimized WS2 composite still kept a high capacity of 482.6 Fg−1 and demonstrated a stable cycling performance during a long-period test. Moreover, an asymmetric capacitor based on assembly of WS2 composite cathode and activated carbon anode was fabricated. As tested under a current density of 0.1 A g−1, it could deliver a high capacitance of ∼135.9 Fg−1 and achieved an energy density of 27.2 Wh kg−1 along with a power density of 59.9 W kg−1.