Mo, Ni, S doped cobalt carbonate hydroxide ultrathin nanosheet arrays on nickel foam for high-performance hybrid supercapacitors

Elemental doping and morphological modulation become important strategies for designing electrode materials of high performance supercapacitor. In this paper, Mo and Ni doped cobalt carbonate hydroxide (CCH) nanoneedle arrays (Ni(OH)₂@Mo, Ni-CCH) on Ni foam (NF) are first obtained by hydrothermal synthesis. After S doping, Ni(OH)₂ nanosheet arrays are cross-linked among Mo, Ni, S doped CCH nanoneedle arrays (Ni(OH)₂@Mo, Ni, S-CCH) on NF at room temperature. The Ni(OH)₂@Mo, Ni, S-CCH/NF demonstrates a remarkable high specific capacity of 1765 C g⁻¹ at 1 A g⁻¹ and cycle life of 82.1 % after 10, 000 cycles, which is attributed to the synergistic effects of high conductive Ni and Mo doped CCH and microstructural modulation after S doping. Upon assembly with activated carbon (AC), the hybrid supercapacitor (HSC) demonstrates an impressive high energy density of 60.15 Wh kg⁻¹ (at 615.51 W kg⁻¹), maintaining a capacity retention ratio of 91.82 % even after 10, 000 cycles. This demonstrates the great potential of Ni(OH)₂@Mo, Ni, S-CCH/NF as an advanced HSC electrode.