Curvature-Induced Modification of Mechano-Electrochemical Coupling and Nucleation Kinetics in a Cathode Material

Authors: Justin L. Andrews, Peter Stein, David A. Santos, Cody J. Chalker, Luis R. De Jesus, Rachel D. Davidson, Michelle A. Gross, Matt Pharr, James D. Batteas, Bai-Xiang Xu, and Sarbajit Banerjee

Intercalation-induced phase transformations in Li-ion battery elec- trode materials give rise to multi-phase coexistence regimes within individual particles, generating significant lattice coherency strain across dynamically evolving interfaces. We demonstrate here that the lattice coherency strain can be alleviated by leveraging the coupling of electrochemistry, mechanics, and particle geometry to achieve controllable nucleation and deterministic ion transport. Here, we contrast singular kinks and continuous curvature as a means of enabling homogeneous lithiation without developing large stresses within a model cathode material, V2O5. The singular kink confirms that local curvature facilitates lithiation but also exacerbates lithiation inhomogeneities and elastic misfit strain. In contrast, the incorporation of continuous curvature enables homo- geneous single-phase lithiation, mitigating lattice coherency strain. The studies provide a direct view of the coupling of mechanics and electrochemistry within crystalline electrodes and suggest that mesoscale architectures can help resolve key failure mechanisms limiting the performance of energy-storage systems without sacri- ficing charge/discharge kinetics..

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