Ni(OH)₂ nanoplates grown on graphene are investigated as electrochemical pseudocapacitor materials for energy storage. Single-crystalline Ni(OH)₂ hexagonal nanoplates directly grown on lightly-oxidized, electrically-conducting graphene sheets exhibit high specific capacitance (1335 F/g at 2.8 A/g and 953 F/g at 45.7 A/g) and excellent cycling stability. These results highlight the importance of direct growth of nanomaterials on graphene for intimate interactions and efficient charge transport. The performance of the composites is dependent on the quality of the graphene substrate and the morphology and crystallinity of the nanomaterials. The high specific capacitance and rate capability of the Ni(OH)₂/GS composite make it promising for supercapacitors with high energy and power densities. The energy density was estimated to be ~37 Wh/kg at a power density of ~10 kW/kg. In contrast, Ni(OH)₂ nanocrystals grown on GO and Ni(OH)₂ nanoplates physically mixed with graphene showed inferior performance. The results suggest that rational design and synthesis of graphene-based nanocomposite materials are important for high-performance energy applications. The study demonstrates that the quality of graphene and the morphology and crystallinity of the nanomaterials are critical factors for the electrochemical performance of these composites. The Ni(OH)₂/GS composite shows high specific capacitance and rate capability, significantly outperforming Ni(OH)₂ nanoparticles on GO and Ni(OH)₂ nanoplates mixed with graphene. The study also highlights the importance of using high-quality, conductive graphene as a substrate and controlling the morphology and crystallinity of the nanomaterials to produce advanced graphene/nanocrystal composite materials for energy applications. The next step is to couple the Ni(OH)₂/GS material with a suitable counter electrode to achieve a large operating voltage range and optimize the energy and power densities of real supercapacitors.Ni(OH)₂ nanoplates grown on graphene are investigated as electrochemical pseudocapacitor materials for energy storage. Single-crystalline Ni(OH)₂ hexagonal nanoplates directly grown on lightly-oxidized, electrically-conducting graphene sheets exhibit high specific capacitance (1335 F/g at 2.8 A/g and 953 F/g at 45.7 A/g) and excellent cycling stability. These results highlight the importance of direct growth of nanomaterials on graphene for intimate interactions and efficient charge transport. The performance of the composites is dependent on the quality of the graphene substrate and the morphology and crystallinity of the nanomaterials. The high specific capacitance and rate capability of the Ni(OH)₂/GS composite make it promising for supercapacitors with high energy and power densities. The energy density was estimated to be ~37 Wh/kg at a power density of ~10 kW/kg. In contrast, Ni(OH)₂ nanocrystals grown on GO and Ni(OH)₂ nanoplates physically mixed with graphene showed inferior performance. The results suggest that rational design and synthesis of graphene-based nanocomposite materials are important for high-performance energy applications. The study demonstrates that the quality of graphene and the morphology and crystallinity of the nanomaterials are critical factors for the electrochemical performance of these composites. The Ni(OH)₂/GS composite shows high specific capacitance and rate capability, significantly outperforming Ni(OH)₂ nanoparticles on GO and Ni(OH)₂ nanoplates mixed with graphene. The study also highlights the importance of using high-quality, conductive graphene as a substrate and controlling the morphology and crystallinity of the nanomaterials to produce advanced graphene/nanocrystal composite materials for energy applications. The next step is to couple the Ni(OH)₂/GS material with a suitable counter electrode to achieve a large operating voltage range and optimize the energy and power densities of real supercapacitors.