N,P-co-doped 2D Carbon Nanosheets for High Energy Density Zinc-Ion Capacitors

Zinc-ion capacitors (ZICs) are regarded as highly promising candidates for electrical energy storage systems (EESs). However, some challenges must be met to achieve high energy density and long cycling life in practical applications. Herein, we report on design and preparation of 2D nanosheets of N,P-co-doped hierarchical porous carbon (GNPCs) by a one-step process. Benefitting from the mesopores supporting rapid diffusive ion transport, sufficient micropores for charge storage, and high electrical conductivity enabled by N,P-doping, the resulting GNPC cathodes for ZICs achieved a high capacity of 401 F g(-1). In a complete device a high energy density of 180 Wh kg(-1) was obtained at a power density of 85 W kg(-1) at 0.1 A g(-1). More importantly, the ZICs exhibit a good cycling stability with a capacity retention of 95 % after 10 000 cycles at a current density of 5 A g(-1). Our work presents a good strategy for developing high-performance carbon-based cathodes for ZICs.

Automated summary

In this study, 2D nanosheets of N,P-co-doped hierarchical porous carbon (GNPCs) were designed and prepared for ZICs as cathodes, which showed high capacity and energy density. The GNPCs exhibited rapid diffusive ion transport, sufficient micropores for charge storage, and high electrical conductivity enabled by N,P-doping. Additionally, the ZICs demonstrated good cycling stability. This work provides a good strategy for the development of high-performance carbon-based cathodes for ZICs.