Construction of CuCo2O4 hollow microspheres/Ti3C2Tx MXene composite for electrode material of hybrid supercapacitors

CuCo2O4 is a promising active electrode material for its considerable theoretical capacities and natural abundance, however, also is plagued by the disadvantages of the intrinsic low electrical conductivity, slow reaction kinetics and relatively low specific capacity in the practical applications, hence, the precise hybridization with high conductivity and active surface matrix is a promising strategy to overcome these limitations. Herein, porous CuCo2O4 hollow microspheres (CuCo2O4-HS) with the diameter of about 500 nm are hybridized with Ti3C2Tx MXene nanosheets (CuCo2O4-HS/MXene) by electrostatic self-assembly. The crystal structure, morphology and elemental composition of prepared CuCo2O4-HS/MXene are confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Electrochemical test results show that the CuCo2O4-HS/MXene-3 electrode delivers an outstanding specific capacity of 1341.4 C g- 1 at 1 A g- 1 and retained excellent cyclic stability of 90.9% retention during 10000 cycles of charge/discharge at 5 A g- 1 . Additionally, the hybrid supercapacitors (HSC) device from CuCo2O4-HS/ MXene-3 demonstrated excellent specific energy of 66.3 Wh kg- 1 and 49.8 W h kg- 1 at specific power of 724.3 W kg- 1 and 7229.8 W kg- 1 respectively. Significantly, two HSCs connected in series can light a commercial blue LED (3 V) for about 10 mins, demonstrating promising prospect for practical applications.