FeCo2O4@FeCo2S4 core-shell nanospheres intercalating into Ti3C2Tx for high-performance all-solid-state supercapacitors

Electrode materials with high electrochemical activity and outstanding stability is of great significance to improve the performance of supercapacitors. A composite material comprised of core-shell FeCo2O4@FeCo2S4 nanospheres and MXene nanosheets was synthesized through solvothermal combined with self-assembly. The FeCo2O4@FeCo2S4-MXene hybrids as electrode materials exhibit a high specific capacitance of 1090.6 F g−1 at 1 A g−1. All-solid-state supercapacitor using FeCo2O4@FeCo2S4-MXene as the positive electrode possesses a high energy density of 49.8 Wh kg−1 at 800 W kg−1and great cycle life with 87.85 % retention over 20,000 cycles at 1 A g−1. The synergistic effect of FeCo2O4@FeCo2S4 and MXene is the main reason for the exceptional electrochemical performance. FeCo2O4@FeCo2S4 anchored to MXene prevents the restacking of MXene, while MXene provides a conductive network for accelerating carrier transfer and a skeleton for preventing FeCo2O4@FeCo2S4 from collapsing during long-term cycling. In view of the above excellent performance, this study provides a feasible idea for future research on high-performance supercapacitors.