Critical Role of Structural Water for Enhanced Li + Insertion Kinetics in Crystalline Tungsten Oxides
Critical Role of Structural Water for Enhanced Li + Insertion Kinetics in Crystalline Tungsten Oxides
复制标题
结构水对于增强结晶氧化钨中锂插入动力学的关键作用
DOI：
10.1149/1945-7111/ac58c8
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发表时间：
2022
影响因子：
3.9
通讯作者：
Augustyn, Veronica
中科院分区：
文献类型：
--
作者：
Mitchell, James B.;Wang, Ruocun;Ko, Jesse S.;Long, Jeffrey W.;Augustyn, Veronica
过渡金属氧化物中的电化学离子插入形成了几种能源技术的基础。过渡金属氧化物在离子插入过程中会表现出缓慢的离子传输和/或相变动力学，这可能会限制其在高速率(<；10分钟)下的性能。用阶梯恒电位电化学阻抗谱(SPEIS)和电化学石英晶体微天平(EQCM)分析了WO_3·H_2O和WO_3薄膜电极在Li+插入过程中结构水在过渡金属氧化物中的作用。与WO_3相比，WO_3·H_2O中结构水的存在改善了Li+的插入动力学，导致插入过程对电位的依赖性较小。纳米结构薄膜的OPANDO电重法和3DBode阻抗分析表明，结构水的存在促进了电荷调节，而没有明显的溶剂共插入，这导致了我们的假设，即WO_3的电化学诱导的结构转变阻碍了电极在较快的时间尺度(<；10min)下的响应。设计具有较少结构转变的受限流体的层状材料，可能会为下一代电化学技术带来更多用途的离子插入主体。
Electrochemical ion insertion into transition metal oxides forms the foundation of several energy technologies. Transition metal oxides can exhibit sluggish ion transport and/or phase-transformation kinetics during ion insertion that can limit their performance at high rates (< 10 min). In this study, we investigate the role of structural water in transition metal oxides during Li+ insertion using staircase potentiostatic electrochemical impedance spectroscopy (SPEIS) and electrochemical quartz crystal microbalance (EQCM) analysis of WO 3· H 2 O and WO 3 thin-film electrodes. Overall, the presence of structural water in WO 3· H 2 O improves Li+ insertion kinetics compared to WO 3 and leads to a less potential-dependent insertion process. Operando electrogravimetry and 3D Bode impedance analyses of nanostructured films reveal that the presence of structural water promotes charge accommodation without significant co-insertion of solvent, leading to our hypothesis that the electrochemically induced structural transitions of WO 3 hinder the electrode response at faster timescales (< 10 min). Designing layered materials with confined fluids that exhibit less structural transitions may lead to more versatile ion-insertion hosts for next-generation electrochemical technologies.