NiCo₂S₄ Nanocone Arrays/Phosphorus‐Doped Hollow Carbon Nanospheres for High‐Performance Supercapacitors

Abstract

Abstract A soft template and hydrothermal method are used to prepare NiCo 2 S 4 nanocone arrays/P‐doped hollow carbon nanospheres (NCS NCAs/PHCS). PHCS is loaded with a large number of vertically grown NCS NCAs on the surface due to phosphorus doping. PHCS is an excellent conductive base material and it can effectively alleviate the structural collapse of NCS NCAs during charging and discharging because of its hollow structure. NCS NCAs with lots of active sites provide fast diffusion channels and excellent electron transmission channels. The synergistic effect between NCS NCAs and PHCS causes the electrode material to show excellent electrochemical properties, such as high specific capacitance (761 C ⋅ g −1 at 1 A ⋅ g −1 ) and excellent cycle stability (the capacitance retention rate is 88.6 % after 10, 000 cycles at 20 A ⋅ g −1 ). The NCS NCAs/PHCS composite is also assembled with PHCS as an asymmetric supercapacitor. It shows a remarkable energy density of 46.5 Wh ⋅ kg −1 at the power density of 777.5 W ⋅ kg −1 . These findings confirm that the NCS NCAs/PHCS composite is an excellent electrode material of supercapacitors.