Enhanced cycling performance of surface-amorphized Co3S4 as robust cathode for supercapacitors

The interfacial engineering via surface amorphization is an effective strategy to regulate the structure and character of material. Herein, a facile hydrothermal method followed by NaBH4 treatment is proposed to fabricate surface-amorphized Co3S4 (SA-Co3S4). XRD and SEM characterization implies the micro flower structure of Co3S4. TEM test further demonstrates the heterointerface between crystal Co3S4 core and defect-rich amorphous Co3S4 surface, which can reduce electron/ion transport path and accelerate internal charge transfer rate, thus enhancing the integral electrical conductivity. Electrochemical measurements imply that the SA-Co3S4 displays satisfying specific capacitance of 1043.9 F g−1 at 0.5 A g−1 and good rate performance. By employing SA-Co3S4 as a cathode, and active carbon as an anode, the asymmetric supercapacitor exhibits a high energy density of 41.9 Wh kg−1 at a power density of 162 W kg−1 and good cycling durability (above 90 % retention rate after 10,000 cycles). This work offers a novel structure design strategy for fabricating cobalt sulfide materials with high conductivity and electrochemical performances.