Microwave-Assisted Rational Designed CNT-Mn3O4/CoWO4 Hybrid Nanocomposites for High Performance Battery-Supercapacitor Hybrid Device

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)-Mn3O4/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 Mn3O4 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-Mn3O4/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-Mn3O4/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.

Automated summary

Researchers have synthesized a carbon nanotube (CNT)-Mn3O4/CoWO4 triple-segment hybrid electrode using a microwave-assisted hydrothermal route. The electrode demonstrates abundant heterointerfaces and interfacial chemical bonds, resulting in high specific capacity, wide operating voltage window, satisfactory rate capability, and excellent cycling stability. This work provides a new tactic to develop high-performance cathodes for advanced battery-supercapacitor devices.