In-situ Complementary XRD- and PDF-CT Investigation of NMC811 Heterogeneous Degradation

Nickel-rich Li(NiMnCo)O2 (NMC811) have emerged as the most promising successor to LiCoO2 cells, and could potentially facilitate ubiquitous adoption of lithium(Li)-ion batteries in mobile and transport devices. However, NMC811 suffers from instability at high voltages which contributes to significant capacity loss, with the underlying degradation mechanism being poorly understood. We propose to use the capabilities of ID15-A to perform a complete in-situ structural study employing X-ray diffraction (XRD) and pair-distribution-function (PDF) computed tomography (CT) to elucidate a full understanding of the heterogenous structural changes throughout the electrode. During cycling of the cells, we aim to obtain spatially-resolved data to understand how local nano-crystalline phenomena propagate the onset of inactive phases, and how the thickness of the electrode promotes regional chemical environments facilitating inhomogeneous cell activity with complimentary tomographic techniques.