Electric field-induced ball-cactus-like CuCo2Sx(OH)y nano-heterostructure towards high-performance supercapacitors

Developing advanced negative electrode materials with high capacity for supercapacitors currently remains a challenge. To address this issue, an effective strategy through a simple electric field-induced anion exchange process was raised to prepare a novel nanostructured CuCo2Sx(OH)(y) heterostructure based on CuCo2S4 nanosheets as the substrate. Notably, the unique nano-heterostructure featured an extremely high area specific capacitance of 2.94 F cm(-2) at 5 mA cm(-2) and exhibited excellent cycle life and rate capacity. Moreover, the corresponding assembled supercapacitors using the obtained CuCo2Sx(OH)(y) heterostructure as the negative electrode exhibited superior capacitive performance. More specifically, the assembled hybrid supercapacitor possessed a high energy density of 0.54 mW h cm(-2) at a power density of 4.01 mW cm(-2) and the capacitance retention rate was 94.7% even after 10 000 cycles, which confirmed the practicality of the synthesized negative electrode material. Density functional theory calculations further showed that an enhanced conductivity and increased OH- adsorption capability could be achieved in the CuCo2Sx(OH)(y) nano-heterostructure. This work presents a feasible and effective in situ anion exchange strategy to construct the CuCo2Sx(OH)(y) nano-heterostructure as a negative electrode material toward high-performance supercapacitors, improving the current deficiency of negative electrode materials.

Automated summary

By utilizing a simple electric field-induced anion exchange process, a novel nanostructured CuCo2Sx(OH)(y) heterostructure was synthesized, which exhibited high area specific capacitance and excellent capacitive performance.