Microwave-Assisted Rational Designed CNT-Mn₃ O₄ /CoWO₄ Hybrid Nanocomposites for High Performance...

Extensive research interest in hybrid battery-supercapacitor (BSH) devices have led to the development of cathode materials with excellent comprehensive electrochemical properties. In this work, carbon nanotube (CNT)-Mn₃ O₄ /CoWO₄ triple-segment hybrid electrode is synthesized by using a two-step microwave-assisted hydrothermal route. Systematic physical characterization revealed that, with the assistance of microwave, granular Mn₃ O₄ and spheroid-like CoWO₄ with preferred orientation, and oxygen vacancies are stacked or arranged on CNTs skeletons to construct a rational designed hybrid nanocomposite with abundant heterointerfaces and interfacial chemical bonds. Electrochemical evaluations show that the synergistic cooperation in CNT-Mn₃ O₄ /CoWO₄ resulted in an ultra-high specific capacity (1907.5 C g^-1 /529.8 mA h g^-1 at 1 A g^-1 ), a wide operating voltage window (1.15 V), the satisfactory rate capability (capacity maintained at 1016.5 C g^-1 /282.3 mA h g^-1 at 15 A g^-1 ), and excellent cycling stability (117.2% initial capacity retention after 13000 cycles at 15 A g^-1 ). In addition, the assembled CNT-Mn₃ O₄ /CoWO₄ //N doped porous carbon (NC) BSH device delivered a stable working voltage of 2.05 V and superior energy density of 67.5 Wh kg^-1 at power density of 1025 W kg^-1 , as well as excellent stability (92.2% capacity retained at 5 A g^-1 for 12600 cycles). This work provides a new and feasible tactic to develop high-performance transition metal oxide-based cathodes for advanced BSH devices.