Self-supporting in situ growth Ni3S2/FL-Ti3C2 (MXene)/Ni composite as positive electrode for asymmetrical supercapacitor

In this work, using foamed nickel as a nickel source, a self-supporting in situ growth binder-free Ni3S2/FL-Ti3C2/Ni electrode with a 2D heterojunction structure was synthesized via a one-step hydrothermal method after etching a few-layer Ti3C2(FL-Ti3C2) MXene. This electrode provides a high specific capacitance of 1752 mF/cm2 in a 3 M KOH electrolyte at 1 mA/cm2 and has excellent rate performance (75.5% at 10 mA/cm2) and electrochemical stability (74.79% after 5000 cycles). An asymmetric supercapacitor is prepared with Ni3S2/Ti3C2/Ni as the positive electrode and AC as the negative electrode. The maximum energy density and the power density are 32.7 μWh/cm2 and 8.0211 mW/cm2, respectively.