The role of structural water within layered and 2D transition metal oxides is an intriguing concept for improving the kinetics of energy storage. One hypothesis driving this research is that such materials may lead to the development of high power, pseudocapacitive energy storage with ‘bulk’ (&gt; 100 nm) oxide materials. Thus far, pseudocapacitance has been viewed as primarily a surface mechanism, and therefore it would be expected that pseudocapacitive oxides would show no mechanical response upon ion storage. Here, we investigate the electro-chemo-mechanics of proton intercalation into crystalline WO3 and crystalline, layered WO3*2H2O using operando atomic force microscopy (AFM) dilatometry. The nanoscale deflections of the AFM tip were measured for both WO3 and WO3*2H2O as a function of potential and cyclic voltammetry sweep rate. The results presented in this talk will demonstrate important differences in the electro-chemo-mechanics of these two tungsten oxides, and point towards the possibility of high power energy storage with layered materials with nanoconfined water molecules.

Operando AFM reveals mechanics of pseudocapacitive energy storage in tungsten oxides

256th National Meeting (2018)

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