High energy density supercapacitors based on porous mSiO2@Ni3S2/NiS2 promoted with boron nitride and carbon

Abstract The development of aqueous high-energy-density and high-power-density supercapacitor electrode materials is urgent, in order to provide a high energy density and safety for asymmetric/symmetric supercapacitors. Here, boron nitride (BN) and carbon functionalized porous mSiO2@Ni3S2/NiS2 composite materials electrode, which has a high specific potential (ΔV) 1.8 V vs. Hg/HgCl2 and achieves a high reversible capacity of about 449.7 F g−1 at 1 A g−1, an outstanding rate capability (81 F g−1 at 20 A g−1), a maximum energy density of 202.5 Wh Kg−1 at a power density of 959.2 W kg−1 at 1 A g−1 with a respectable capacitance retention of 200% after 8000 cycles at 9 A g−1, and an energy density of 36.38 Wh Kg−1 at a high power density of 17.698 KW kg−1. The as-fabricated aqueous symmetric supercapacitor was assembled and exhibited a working voltage of 1.8 V with a high energy density of 41.67 Wh Kg−1 and power density of 1000 W kg−1 at 1 A g−1. This work offers a new electrode-design paradigm toward transition metal sulfide electrode materials for application in high energy density and high power density energy storage devices.