Novel synthesis of polyaniline, manganese oxide and nickel sulfide lavandula-like composites as efficient active material of supercapacitor

Transition metal sulfides (TMS) are considered as the efficient battery-type material due to high theoretical capacity, redox reversibility, and electrical conductivities. The Ni3S2 with a high theoretical capacity and abundant sources is one of the efficient energy storage materials, but high contact resistances and poor cyclic stability of Ni3S2 restrict its electrochemical performance. The binder-free design, morphology regulation, composite development, and conductive polymer incorporation are useful strategies for solving the problems of Ni3S2. In this study, a novel lavandula-like manganese oxide, Ni3S2 and polyaniline composite (PANI/MnOx/ Ni3S2) is synthesized on Ni foam as the binder-free battery-type electrode of battery supercapacitor hybrid (BSH) as clean energy sources at the first time. The Mn amounts and aniline electropolymerization durations play important roles on active sites and electrical conductivity. The functions of MnOx and PANI are analyzed by comparing physical and electrochemical properties of Ni3S2, MnOx/Ni3S2, PANI, PANI/Ni3S2 and PANI/MnOx/ Ni3S2 electrodes. The largest specific capacitance (CF) of 9.5 F/cm2 at 30 mA/cm2 is achieved for the optimized PANI/MnOx/Ni3S2 electrode. A BSH assembled using activated carbon and PANI/MnOx/Ni3S2 electrodes pre-sents the maximum energy density of 2.31 Wh/m2 at 65 W/m2, and the CF retention of 78.5 % and Coulombic efficiency of 95.8 % after 10,000 times repeatedly charging and discharging process.