Intrinsic defects, including oxygen vacancies, can efficiently modify the electrochemical performance of metal oxides. There is, however, a limited understanding of how vacancies influence charge storage properties. Here, using tungsten oxide as a model system, an extensive study of the effects of structure, electrical properties, and charge storage properties of oxygen vacancies is carried out using both experimental and computational techniques. The results provide direct evidence that oxygen vacancies increase the interlayer spacing in the oxide, which suppress the structural pulverization of the material during electrolyte ion insertion and removal in prolonged stability tests. Specifically, no capacitive decay is detected after 30 000 cycles. The medium states and charge storage mechanism of oxygen‐deficient tungsten oxide throughout electrochemical charging/discharging processes is studied. The enhanced rate capability of the oxygen‐deficient WO_3−x is attributed to improved charge storage kinetics in the bulk material. The WO_3−x electrode exhibits the highest capacitance in reported tungsten‐oxide based electrodes with comparable mass loadings. The capability to improve electrochemical capacitance performance of redox‐active materials is expected to open up new opportunities for ultrafast supercapacitive electrodes.

中文翻译：

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氧空位的电和结构双重功能，可促进氧化钨中的电化学电容

包括氧空位在内的固有缺陷可以有效地改变金属氧化物的电化学性能。但是，关于空位如何影响电荷存储特性的理解有限。在这里，使用氧化钨作为模型系统，使用实验和计算技术对氧空位的结构，电学性质和电荷存储性质的影响进行了广泛的研究。结果提供了直接的证据，表明氧空位增加了氧化物中的层间距，从而在长时间的稳定性测试中抑制了电解质离子插入和去除过程中材料的结构粉碎。具体而言，在30 000次循环后未检测到电容衰减。研究了整个电化学充放电过程中缺氧氧化钨的介质状态和电荷存储机理。缺氧WO的增速能力_{3- x}归因于块状材料中电荷存储动力学的改善。在报告的氧化钨基电极中，WO _{3- x}电极具有最高的电容，且具有可比的质量负载。有望提高氧化还原活性材料的电化学电容性能，这将为超快超电容电极开辟新的机遇。