Preparation of binder-free three-dimensional N-doped carbon framework/ nickel cobaltate composite for all-solid supercapacitor application

摘要

Nickel cobaltate (NCO)with high pseudo-capacitance is mostly micron materials, and agglomeration is prone to occur in the process of electrode reaction. In this paper, the method of secondary hydrothermal precipitation, dissolution and regrowth is used to transform the micron materials into nano-scale and loaded them on the nitrogen-doped three-dimensional reduced graphene carbon framework (NCF) to improve the occurrence of reunion. Binder-free NCF/NCO electrode material has excellent specific capacitance (1576.5 F g-1 at 1 A g-1) and stable cycle performance (the rate of capacity retention after 5000 cycles at 10 A g-1 is 93.1%). N doping changes the surface wettability and electron distribution, and the three-dimensional interconnected structure realizes rapid electron transport and ion diffusion of electrode materials. The NCF/NCOAC assembled into an all-solid capacitor has an energy density of 21.0 Wh kg-1 at a power density of 560.0 W kg-1 and an energy density of 13.6 Wh kg-1 at a power density of 7.0 kW kg-1 which can be used as a power storage device.