Scalable synthesis of macroscopic porous carbon sheet anode for potassium-ion capacitor

Carbon materials hold the great promise for application in energy storage devices owing to their low cost, high thermal/chemical stability, and high electrical conductivity. However, it remains challenging to synthesize high-performance carbon electrodes in a simple, scalable and sustainable way. Here, we report a facile method for scalable synthesis of porous carbon anode by using cheap and easily accessible zeolitic imidazolate framework-8 as a template and polyvinylpyrrolidone as an additional carbon source. The obtained porous carbon shows the macroscopic sheet-like morphology, which has the highly disordered structure, expanded interlayer spacing, abundant pore structure, and nitrogen doping properties. This porous carbon anode is demonstrated to have the excellent K^(+) charge storage properties in specific capacity, rate capability, and cycling stability. A potassium-ion capacitor assembled by using this porous carbon as the anode, delivers a maximum energy density of 85.12 Wh/kg and power density of 11860 W/kg as well as long cycle life exceeding 3000 cycles. This represents a critical advance in the design of low cost and scalable carbon material for applications in energy storage devices.