Synergistic superlattice engineering of cobalt manganese layered-double hydroxide/delaminated-mxene hybrid composite for advanced performance supercapacitors

Layered double hydroxides (LDHs) are promising electrode materials for supercapacitor applications owing to their high specific capacities and tunable compositions. However, poor conductivity, natural tendency to agglomerate, insufficient long-term stability, and high synthesis cost of LDHs limit their widespread adoption. A precise hybridization approach- integrating LDHs with a rigid, conductive, and electroactive surface matrix via a simple and low-cost synthesis technique, has emerged as an effective way to mitigate these challenges. Herein, we forwarded a superlattice engineering strategy to construct a nanohybrid composite by integrating the 3D superstructures of 2D CoMn-LDH nanosheets onto dimethyl sulfoxide (DMSO, (CH₃)₂-S = O) functionalized Ti₃C₂T_x (D-MXene) scaffold via room-temperature co-precipitation. The proposed CoMn-LDHs@D-MXene hybrid composite exhibited a specific capacity of 148 mAh/g at current density of 1 mA/cm², pronounced rate capability of 56.5%, and remarkable long-term cyclic durability of 92.78%. Moreover, a high-performance hybrid asymmetric supercapacitor device based on this proposed hybrid composite (CoMn-LDH@D-MXene//N-doped graphene hydrogels) was assembled which delivered a specific energy density of 37.34 Wh/kg at a power density of 212 W/kg and long-term durability with 92% capacity retention after 5000 cycles. This simple, economical, and efficient synthesis route paves a promising pathway for advancing next-generation supercapacitor technologies.