In situ interfacial engineering of MXene@ZnCo-LDH heterostructures for high performance supercapacitors

MXenes are regarded as promising electrode materials for supercapacitors due to their high electrical conductivity and two-dimensional layered architecture. However, nanosheet restacking constricts ion-transport pathways, which limits rate capability and cycling stability. Here, Ti3C2Tx MXene was used as a conductive substrate and ZnCo layered double hydroxide (ZnCo-LDH) was grown in situ on the MXene surfaces and within the interlayers via a one-step hydrothermal method. The resulting MXene@ZnCo-LDH composite electrode enables synergistic regulation of interlayer spacing and interfacial charge storage. Structural characterization reveals that ZnCo-LDH nanosheets are firmly anchored on MXene surfaces and between layers. This architecture suppresses restacking and creates open ion-transport channels, thereby facilitating fast charge–discharge kinetics. Electrochemical measurements show that the optimized composite (MZC-4) exhibits favorable rate capability and excellent capacitance retention during long-term cycling at high current density. Furthermore, the assembled AC//MXene@ZnCo-LDH asymmetric supercapacitor operates stably within a 1.6 V window. It retains 86.62% of its initial capacitance after 5000 charge–discharge cycles at 5 A g−1, with a coulombic efficiency of 95.39%. First-principles calculations reveal interfacial charge redistribution and electronic-state modulation, which are consistent with the experimentally observed lower charge-transfer resistance and favorable charge-transport behavior. These results demonstrate that the MXene@ZnCo-LDH composite electrode provides an effective platform for balancing rate capability and long-term cycling stability in supercapacitor applications.