Electron Energy Loss Spectroscopy (EELS)

Electron energy-loss spectroscopy (EELS) measures the energy lost by electrons as they pass through a thin specimen in a transmission electron microscope, revealing elemental composition, oxidation state, bonding, and electronic structure at near-atomic resolution. As a hard skill it requires preparing electron-transparent specimens, acquiring spectra with high signal-to-noise, and performing background subtraction, multiple-scattering correction, and quantitative analysis using reference cross-sections. Battery researchers apply EELS to probe lithiation-state gradients, transition-metal valence changes, and interfacial chemistry in cathodes and solid electrolytes at a spatial scale no other technique can match.

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