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

Abstract 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)‐Mn 3 O 4 /CoWO 4 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 Mn 3 O 4 and spheroid‐like CoWO 4 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‐Mn 3 O 4 /CoWO 4 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‐Mn 3 O 4 /CoWO 4 //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.