Facile synthesis of Ni doped BiOBr nanosheets as efficient photo-assisted charging supercapacitors

Enhanced visible light-driven pseudocapacitance response of Ni doped BiOBr (Ni-BiOBr) nanosheet is successfully synthesized via a facile precipitation. An obvious efficient dopant of Ni atom onto BiOBr structure can expand the light absorption range and enhance the photogenerated carrier separation efficiency. Once illuminated under UV light, Ni-BiOBr photoelectrode can deliver the highest specific capacitance of the 362.73 F g−1 at 0.5 A g−1, which is 1.45 times larger than that of dark condition. Additionality, the asymmetric supercapacitors of Ni-BiOBr//reduced graphene oxide offer the energy density of 39.95 Wh kg−1 at power density of 725 W kg−1 and can maintain 68% capacitance retention at 5 A g−1 after 1000 cycles under light irradiation. The band alignment and mechanism of photo-assisted charging supercapacitor of Ni-BiOBr//reduced graphene oxide are proposed. This work presents a novel class of material for photo-assisted charging supercapacitors, utilizing solar energy to enhance storage capacity.