Ti3C2-Mxene-dispersion and morphology controlled battery-type nickel cobalt sulphide based nanocomposites for the application as aqueous asymmetric supercapacitor with improved rate

Nickel cobalt sulphide (NiCo 2 S 4 ) is a promising battery-type electrode material due to its high theoretical capacitance and rich redox activity. However, its poor electrical conductivity and structural instability hinder practical application. Incorporation of two-dimensional (2D) Ti 3 C 2 MXene can address these issues by improving conductivity and mechanical integrity. While previous studies have explored the synergistic effects of Ti 3 C 2 and NiCo 2 S 4 , the influence of MXene exfoliation state and morphology control on electrochemical performance remains underexplored. Herein, we report a one-step hydrothermal synthesis of delaminated Ti 3 C 2 @NiCo 2 S 4 (d-Ti 3 C 2 @NiCo 2 S 4 ) composites with tunable morphology by varying hydrothermal time (4–48 h). Among them, the 24 h sample (d-Ti 3 C 2 @NiCo 2 S 4 -24) featuring a hexagonal layered platelet structure exhibits superior performance, delivering 161.94 mAh g −1 (1165 F g −1 ) at 1 A g −1 , with ~ 81% rate capability at 5 A g −1 and 85% capacity retention over 20,000 cycles. It significantly outperforms both bare NiCo 2 S 4 -24 and the multilayer Ti 3 C 2 -based composite. The asymmetric device (d-Ti 3 C 2 @NiCo 2 S 4 -24//AC) delivers 19.88 Wh kg −1 at 399.82 W kg −1 with 86% retention after 9000 cycles, demonstrating excellent potential for practical energy storage applications.