Electrochemical Activation-Induced Structural Transformation in Ni(OH)2/Ti3C2Tx/NF Systems with Enhanced Electrochemical Performance for Hybrid Supercapacitors

Abstract

Exploring a novel strategy for large-scale production of battery-type Ni(OH)2-based composites, with excellent capacitive performance, is still greatly challenging. Herein, we developed a facile and cost-effective strategy to in situ grow a layer of Ni(OH)2/Ti3C2Tx composite on the nickel foam (NF) collector, where Ti3C2Tx is not only a conductive component, but also a catalyst that accelerates the oxidation of NF to Ni(OH)2. Detailed analysis reveals that the crystallinity, morphology, and electronic structure of the integrated electrode can be tuned via the electrochemical activation, which is beneficial for improving electrical conductivity and redox activity. As expected, the integrated electrode shows a specific capacity of 1.09 C cm−2 at 1 mA cm−2 after three custom activation cycles and maintains 92.4% of the initial capacity after 1500 cycles. Moreover, a hybrid supercapacitor composed of Ni(OH)2/Ti3C2Tx/NF cathode and activated carbon anode provides an energy density of 0.1 mWh cm−2 at a power density of 0.97 mW cm−2, and excellent cycling stability with about 110% capacity retention rate after 5000 cycles. This work would afford an economical and convenient method to steer commercial Ni foam into advanced Ni(OH)2-based composite materials as binder-free electrodes for hybrid supercapacitors.