Hierarchical Co-doped SnS2@Ni(OH)2 double-shell crystalline structure on carbon cloth with gradient pore distribution for superior capacitance†
Abstract
Hierarchical Co-doped SnS2@Ni(OH)2 double-shell nanosheet arrays are coated on carbon cloth via a two-step solvothermal method. The vertically aligned and ultrathin nanosheet arrays with gradient pore distribution and hydrophilic nature can facilitate electrolyte infiltration and avoid the “dead volume,” while the densely-packed SnS2 array with high intrinsic electrical conductivity can bridge carbon cloth and Ni(OH)2 to improve electron transfer. The SnS2@Co–Ni(OH)2/CC-3 electrode can achieve high areal capacitance (5.41 F cm−2 at 1 mA cm−2), good rate capability, and cyclic stability (93.92% capacitance retention after 5000 cycles) in a three-electrode system. Moreover, an asymmetric supercapacitor (ASC) device is fabricated with the help of SnS2@Co–Ni(OH)2/CC composites and activated microwave-exfoliated graphene oxide, which achieves the highest energy density of 57.2 W h kg−1 and a maximum power density of 8.0 kW kg−1.