Construction of porous carbon nanosheets by dual-template strategy for zinc ion hybrid capacitor

Carbonaceous zinc ion hybrid capacitors (CZHCs) have attracted numerous interests thank to the advantages of large energy density of zinc-ion battery and excellent security and high power density of supercapacitors. Nevertheless, the preparation of carbon cathode is relatively complex, and it is urgent to develop a simple and efficient preparation method. Herein, the porous carbon nanosheets (C-Xs) were prepared by dual-template strategy combined K2CO3 activation from anthracene molecules, which present unique layered sheet-like structures and high surface area, displaying excellent zinc storage properties as cathode for Zn parallel to C-X ZHCs. Zn parallel to C-800 ZHC achieves high discharge capacity of 121.7 mAh g(-1), maximum energy density and power density of 109.3 Wh kg(-1) and 15.6 kW kg(-1) in 3 M ZnSO4 electrolyte, respectively. Moreover, the capacity retention of 96.2% and coulombic efficiency of similar to 100% is obtained after 30,000 cycles. This work opens up a simple and efficient rout for the synthesis of carbon nanosheet cathode by dual-template strategy for ZHC.

Automated summary

Carbonaceous zinc ion hybrid capacitors (CZHCs) have gained considerable attention due to their high energy density from zinc-ion batteries and the excellent safety and high power density from supercapacitors. However, the complex preparation process for the carbon cathode necessitates the development of a simple and efficient method. This study demonstrates the synthesis of porous carbon nanosheets (C-Xs) through a dual-template strategy and K2CO3 activation of anthracene molecules, resulting in layered sheet-like structures with high surface area. The Zn-C-Xs ZHC cathode exhibits outstanding zinc storage properties, achieving a discharge capacity of 121.7 mAh g(-1), maximum energy density of 109.3 Wh kg(-1), and power density of 15.6 kW kg(-1) in a 3M ZnSO4 electrolyte. After 30,000 cycles, it maintains a capacity retention of 96.2% and a coulombic efficiency close to 100%. This work presents a simple and efficient route for the synthesis of carbon nanosheet cathodes using a dual-template strategy for ZHCs.