A platform for in situ Raman and stress characterizations of V2O5 cathode using MEMS device

• A novel in situ characterization method for Li-ion battery research is proposed.
• Structural evolutions of δ- to γ-phase and γ- to ω-phase in LixV2O5 are visualized.
• Stress variation with different phases of LixV2O5 are characterized.
• Concomitant with the stress, in situ Raman spectra are collected and analyzed.

We present an in situ approach for the characterization of lithium intercalation/deintercalation in thin-film Li-ion battery electrodes. The method allows simultaneous measurement of microstructural changes during lithiation using micro-Raman (μRaman) spectroscopy in parallel with stress changes via optical interferometry. We observe evolution in the microstructure and stress in the various crystal phases in the Li-V-O system, including both reversible and irreversible phase transitions. We also correlate spectral shifts in certain Raman active modes with changes in the electrode stress, and thus confirm previously hypothesized origins of these observations. Ultimately, the combined stress/μRaman in situ technique can be leveraged as a characterization platform for a wide variety of electrode materials for advancing battery performance.

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