Modulation of the electronic structure of tunneling VO2 by tungsten for ammonium-ion hybrid supercapacitors

• Published in: Journal of power sources Vol. 643; p. 237021
• Main Authors: Zhou, Zhenhua, Zhang, Yifu, Xu, Mingli, Tan, Xianfang, Lv, Tianming, Zheng, Jiqi, Meng, Changgong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2025
• Subjects: Ammonium-ion storage; Doping; Oxygen defect; Supercapacitors; VO2; Ammonium-ion storage; VO2; Supercapacitors; Oxygen defect; Doping
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2025.237021

In recent years, aqueous ammonium-ion supercapacitors (NH4+-SCs) have been the subject of considerable interest due to their favorable safety profile and low cost. Exploring high-performance electrode materials remains a hot research topic in this field. The monoclinic vanadium oxides (VO2) as a group of vanadium oxides has a tunneling structure that favors NH4+ migration. However, its application in SCs as the anode material has been rarely reported, and enhancing the storage capacity of NH4+ by modulating its electronic structure is challenging. In this study, we design and synthesize W-doped VO2 (named as VOW) with a unique nanobelt morphology by adjusting the W content. It has a suitable oxygen defect and excellent electrochemical properties for efficient storage of ammonium-ions. It is proved that the introduction of W can effectively modulate its electrochemical performance, and 1 % doping of W atoms is the most obvious for VO2 performance enhancement. The hybrid supercapacitor (HSC) with the VOW as the anode with the PANI as the cathode has superior cycling stability and energy output capability. The capacitance after 6000 cycles is as high as 83 %, and the energy density (E) reaches 64 Wh·kg−1 at the power density (P) of 119 W kg−1. In this work, it shows a new approach for modulating and developing electrode materials for high-performance NH4+ storage. This work proves that the W-doping is an efficient strategy for boosted NH4+-storage of VO2. VOW delivers the specific capacitance of 1038 F g−1 (288 mAh·g−1) at 0.2 A g−1. This strategy provides a new idea for the development of high-performance NH4+-SCs. [Display omitted] •W-doped VO2 (VOW) is designed and it shows good NH4+-storage.•VOW with 1 % W-doping shows the best electrochemical properties.•The specific capacity of VOW is 1038 F g−1 at 0.2 A g−1.•The HSC delivers the energy density of 64 Wh·kg−1 at 119 W kg−1.