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Title: Critical Role of Structural Water for Enhanced Li + Insertion Kinetics in Crystalline Tungsten Oxides
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.  more » « less
Award ID(s):
1653827
PAR ID:
10342197
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Journal of The Electrochemical Society
Volume:
169
Issue:
3
ISSN:
0013-4651
Page Range / eLocation ID:
030534
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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