A novel Ni(OH)2/graphene nanosheets electrode with high capacitance and excellent cycling stability for pseudocapacitors

A novel Ni(OH)2/graphene nanosheets (GNs) composite with Ni(OH)2 nanoflakes dispersing within a 3D fluffy and conductive graphene network has been successfully prepared by a facile hydrothermal reaction for pseudocapacitor applications. Using the as-prepared Ni(OH)2/GNs composite as active material, the pseudocapacitor electrode exhibits very high capacitance and encouraging rate capability, as indicated by the experimental results that its specific capacitance is 2260 F g−1 at a current density of 1 A g−1 and 1401 F g−1 when the current density is increased to 10 A g−1 (61.9% retention). In addition, its shows remarkable long-term cycling stability, with a high capacitance retention of 115.6% at 100 mV s−1 after 4000 cycles and only 2.6% of decay at a current density of 16 A g−1 over 1000 cycles. The excellent electrochemical performance of the Ni(OH)2/GNs composite electrode is ascribed to its enhanced ion and electron transport kinetic arising from its unique microstructure, namely a 3D electron conductive graphene network with ion diffusive fluffy pathways. Therefore, the Ni(OH)2/GNs composite electrode is a promising candidate for high performance pseudocapacitors; the fluffy crystalline GNs are promising matrix for advanced energy materials with ensured ion and electron conductivities.