Facile fabrication of CuCo2S4 nanoparticles/MXene composite as anode for high-performance asymmetric supercapacitor

A novel organ-like Ti3C2Tx/CuCo2S4 composite was synthesized via a hydrothermal method by forming well-defined and uniformly dispersed CuCo2S4 nanoparticles on Ti3C2Tx nanosheets. Mainly owing to the increase in conductivity, electron/ion transport capacity and the structural stability of the Ti3C2Tx/CuCo2S4 composite in 6 M KOH electrolyte, the MXene/CuCo2S4 composite material exhibited enhanced performance (992.3 C g(-1) at 1 A g(-1)) compared with pristine CuCo2S4 (675.2 C g(-1) at 1 A g(-1)) and Ti3C2Tx MXene (92.3 C g(-1) at 1 A g(-1)). In addition, an asymmetric supercapacitor (ASC) was built with Ti3C2Tx MXene/CuCo2S4 as the positive electrode and activated carbon (AC) as the negative electrode (MXene/CuCo2S4//AC). This ASC device exhibited a specific capacity of 269.4 C g(-1) at 1 A g(-1) in the potential range from 0 to 1.6 V. The maximum specific energy of 66.8 W h kg(-1) at a specific power of 895.1 W kg(-1) was obtained with an 88.2% capacity retention after 10 000 charge-discharge cycles at a current density of 8 A g(-1). Moreover, the ASC device also showed 89.7% capacity retention at floating time over 200 h at 8 A g(-1). These results illustrate MXene/CuCo2S4 as a promising electrode for supercapacitors.