Zhang Zhaocheng, Mo Huajing, Li Ruicong, Zhou Xinglong, Lin Zicong, Zhang Jiong, Tang Xiufeng, Zhan Yunfeng, Luo Jianyi
School of Applied Physics and Materials Wuyi University Jiangmen 529020 China.
School of Civil Engineering and Architecture Wuyi University Jiangmen 529020 China.
Small Sci. 2024 Jan 20;4(3):2300219. doi: 10.1002/smsc.202300219. eCollection 2024 Mar.
Defect engineering of electrode materials is considered highly effective in regulating their performance, among which oxygen vacancies play a vital role. Thereupon, comprehensively understanding effects of oxygen vacancy in electrochemical processes of transition metal oxides stays hot and controversial, representatively for amorphous tungsten oxide films and their electrochromic (EC) behaviors. Upon long-term cycling, amorphous tungsten oxide suffers from the universal trapping effect governed by the intrinsic host microstructure and transport kinetics of the inserted ions, implying that manipulating oxygen vacancies could be a potential solution to the ion-trapping problem. Hence, systematic work is urgent for not only tackling the trapping effect but also understanding the effect of oxygen vacancies on EC behaviors. Herein, the concentration of oxygen vacancies in the amorphous tungsten oxide films is modulated over a wide range. In combination with comprehensive experiments and first-principles calculations, the presence of oxygen vacancy is detrimental to the EC properties, but it greatly attenuates the trapping effect. Excellent cyclic stability is achieved with a 100% optical modulation rate and charge capacity retention after 5000 cyclic voltammetry cycles. This study elucidates understanding of oxygen vacancy engineering in transition metal oxides, particularly regarding trapping effect passivation.
电极材料的缺陷工程被认为是调节其性能的高效方法，其中氧空位起着至关重要的作用。因此，全面了解氧空位在过渡金属氧化物电化学过程中的作用一直是热门且有争议的话题，以非晶态氧化钨薄膜及其电致变色（EC）行为最为典型。在长期循环过程中，非晶态氧化钨会受到由固有主体微观结构和插入离子的传输动力学所控制的普遍俘获效应的影响，这意味着调控氧空位可能是解决离子俘获问题的一个潜在方案。因此，开展系统性工作不仅对于解决俘获效应至关重要，而且对于理解氧空位对电致变色行为的影响也很迫切。在此，非晶态氧化钨薄膜中的氧空位浓度在很宽的范围内得到调控。结合全面的实验和第一性原理计算，发现氧空位的存在对电致变色性能不利，但它能极大地减弱俘获效应。在5000次循环伏安循环后，实现了100%的光学调制率和电荷容量保持率，从而获得了优异的循环稳定性。这项研究阐明了对过渡金属氧化物中氧空位工程的理解，特别是关于俘获效应的钝化。
