Hierarchical porous 3D NiCoZn-se heterojunction nanosheets for high-performance flexible supercapacitor

Transition metal selenides have attracted much attention as an electrode material with an ideal composition. However, there is still a lack of in-depth research on the design of its microstructure. In this paper, porous folded nickel-cobalt-zinc-selenide electrode materials were obtained by using hydrothermal method with annealing. This structure provides a large number of active sites and shortens the ion diffusion pathway, thus facilitating the enhancement of electrochemical processes. The finite element analysis shows that the pleated structure has more excellent mechanical properties. Therefore, it was used as an electrode material, exhibiting an area specific capacitance of 2475 mF cm- 2 at a current density of 2 mA cm- 2. The capacity retention rate of the electrode is still as high as 81.0 % after 5000 cycle tests. To further validate its practical application, an asymmetric supercapacitor (ASC) consisting of NiCoZn-Se electrodes and activated carbon (AC) electrodes was fabricated. The device exhibited an area specific capacitance of 950 mF cm- 2 at 4 mA cm- 2 and still had 82 % of the initial capacity after 8000 cycles. In addition, the flexibility test shows that the device still maintains good electrochemical performance at different bending angles. These findings indicate that this electrode material has significant potential for application.