Facile synthesis of CoNi2S4 nanoparticles grown on carbon fiber cloth for supercapacitor application

A facile one-step hydrothermal route has been developed to directly synthesize CoNi 2 S 4 nanoparticles on carbon fiber cloth (CC) to study the synergistic effect of bimetallic sulfides and carbon substrate on the electrochemical performance of supercapacitor electrode. The integrated binder-free CoNi 2 S 4 /CC electrode possesses an outstanding specific capacitance of 1165 F g −1 at 1 A g −1 , and excellent rate capacitance (75.3% retention at 10 A g −1 ) in a three-electrode system, which is 27.2% and 32.2% higher than that of pure CoNi 2 S 4 electrode. Detailed electrochemical tests and results showed that the surface capacitance effect ratio of the CoNi 2 S 4 /CC electrode is higher than that of pure CoNi 2 S 4 electrode because of the introduction of CC. The CC substrates can provide a channel for electrolyte electrons and ions to promote reaction kinetics and shorten the diffusion distance of the redox reaction, thereby improving the performance of the pseudocapacitor CoNi 2 S 4 . Besides, the assembled asymmetric supercapacitors based on CoNi 2 S 4 /CC electrode and reduced graphene oxide electrode displayed a high specific energy density of 33.2 Wh kg −1 at 800 W kg −1 , remarkable electrochemical stability (87.1% retention after 10,000 circulations) and high rate stability.