In situ Ni-doped CoMoO4 nanomaterials on acid-pretreated nickel foam with high capacitive properties

Different from conventional methods that synthesize Ni-doped nanomaterials by introducing external Ni sources, this study developed an in-situ doping strategy using Hydrochloric acid, nitric acid, sulfuric acid, and oxalic acid treatments generated corresponding nickel salts (NiCl₂, Ni(NO₃)₂, NiSO₄, and NiC₂O₄) on nickel foams as Ni sources, enabling one-step hydrothermal synthesis of Ni-doped CoMoO₄ nanoelectrodes. The in situ Ni-doped CoMoO₄ nanomaterials synthesized on the four acidified pretreated nickel foams exhibited specific capacitances of 4680, 4500, 2700, and 2250 mF cm⁻² at 5 mA cm⁻², respectively, significantly exceeding the 1690 mF cm⁻² achieved by undoped CoMoO₄ on conventional clean foams. An asymmetric supercapacitor (ASC) assembled with activated carbon and Ni-doped CoMoO₄ electrode material synthesized on hydrochloric acid pretreated nickel foam demonstrated a specific capacitance of 690 mF cm⁻² at 5 mA cm⁻², along with a high energy density of 160.4 Wh·kg⁻¹ at 2600 W kg⁻¹ power density. Remarkably, the ASC retained 95 % capacitance after 10,000 cycles. These results highlight the potential of in-situ Ni-doped CoMoO₄ as a high-performance electrode material for advanced supercapacitors.