Ti₃C₂T_x MXene-Coupled NiCo-Layered Double Hydroxide Nanosheets with Entire Contact for High-Performance Supercapacitors

Layered double hydroxides (LDHs) have been known as attractive alternative electrodes for supercapacitors. However, the restacking of LDHs and poor conductivity still limit their further application. To address these critical issues, in this work, the NiCo-LDH/Ti3C2Tx nanosheet composites with strong contact have been fabricated by introducing Ti3C2Tx MXenes as the structure-directing substrate. It is found that NiCo-LDH can duplicate the MXene structure to generate sufficient contact, accelerating the electron transfer and exposing abundant electroactive sites to enhance the electrochemical kinetics. The theoretical analysis further confirms that the redox reaction kinetics of the electroactive NiCo-LDH nanosheets can be enhanced by Ti3C2Tx MXenes. Because of these advantages, the as-made NiCo-LDH/Ti3C2Tx electrode shows a good specific capacitance of 1030 F g–1 at 1 A g–1 with a competitive capacitance retention (61% of its initial specific capacitance at 50 A g–1). The resultant asymmetric supercapacitor constructed by NiCo-LDH/Ti3C2Tx can achieve a maximum energy density of 59 W h kg–1 at a power density of 0.8 kW kg–1.