Heterostructured MoO3@CoWO4 nanobelts towards high electrochemical performances via oxygen vacancies generation

Heterostructured nanomaterials tend to have a high proportion of oxygen vacancies (VO) due to the presence of heterogeneous interfaces. Herein, a new kind of heterostructured MoO3@CoWO4 nanobelts was successfully evaluated as fascinating cathode material. SEM and TEM analysis indicated that the MoO3 nanobelts were fully blanketed with CoWO4 nanodots. The generation of Vo species was confirmed by XPS and EPR data. By profiting both synergistic and Vo generation effects, MoO3@CoWO4 electrode displayed an excellent capacitance of 246 mAh·g−1 (1966 F·g-1at 0.5 A·g−1) with high-rate capability of 174 mAh·g−1 (1394 F·g−1 at 30 A·g−1) as well as superb stability of 94 % (over 15,000 cycles). Notably, all-solid-state device delivered a good energy value of 63.1 Wh·kg−1 at 375 W·kg−1. Interestingly, the supercapacitor device showed super-low self-discharge comportment of only 12.1 % during 24 h. Importantly, the generation of the VO defects could control the ions diffusion process and lead a sharp decrease in the self-discharge process.