Hydrothermal Synthesis of Nickel Phosphate Nanorods for High-Performance Flexible Asymmetric All-Solid-State Supercapacitors

Ni-20[(OH)(12)(H2O)(6)][(HPO4)(8)(PO4)(4)]center dot 12H(2)O nanorods are successfully synthesized via a one-pot hydrothermal reaction. A high-performance flexible asymmetric all-solid-state supercapacitor based on the obtained Ni-20[(OH)(12)(H2O)(6)][(HPO4)(8)(PO4)(4)]center dot 12H(2)O nanorods (positive electrode) and graphene nanosheets (negative electrode) is successfully assembled. It is the first report of this nanomaterial applied for all-solid-state supercapacitors. Interestingly, a maximum volumetric energy density of 0.446 mW h cm(-3) at a current density of 0.5 mA cm(-2) and a maximum power density of 44.1 mW cm(-3) at a current density of 6.0 mA cm(-2) are achieved by the as-assembled device. What's more, the device also shows excellent mechanical flexibility and little capacitance change after over 5000 charge/discharge cycles at a current density of 0.5 mA cm(-2).