Ultrathin Ni(OH)2 layer coupling with graphene for fast electron/ion transport in supercapacitor

Integration of fast electrochemical double-layer capacitance and large pseudocapacitance is a practical way to improve the overall capability of supercapacitor, yet remains challenging. Herein, an effective cyanogel synthetic strategy was demonstrated to prepare ultrathin Ni(OH)(2)nanosheets coupling with conductive reduced graphene oxide (rGO) (rGO-Ni(OH)(2)) at ambient condition. Ultrathin Ni(OH)(2)nanosheet with 3-4 layers of edge-sharing octahedral MO(6)maximally exposes the active surface of Faradic reaction and promotes the ion diffusion, while the conductive rGO sheet boosts the electron transport during the reaction. Even at 30 A g(-1), the optimal sample can deliver a specific capacitance of 1119.52 F g(-1), and maintain 82.3% after 2000 cycles, demonstrating much higher electrochemical capability than bare Ni(OH)(2)nanosheets. A maximum specific energy of 44.3 W h kg(-1)(148.5 W kg(-1)) is obtained, when assembled in a two-electrode system rGO-Ni(OH)(2)//rGO. This study provides an insight into efficient construction of two dimensional hybrid electrodes with high performance for the new-generation energy storage system.

Automated summary

The integration of fast electrochemical double-layer capacitance and large pseudocapacitance by synthesizing ultrathin Ni(OH)(2) nanosheets coupled with conductive reduced graphene oxide (rGO) shows significant improvement in overall performance of supercapacitors. The hybrid material exhibits higher specific capacitance and cycle stability compared to bare Ni(OH)(2) nanosheets, demonstrating enhanced electrochemical capability. This study provides insights into constructing high-performance two-dimensional hybrid electrodes for the new-generation energy storage system.