Dislocation-induced artifacts in cyclic voltammetry of battery materials

Abstract This review establishes that crystallographic dislocations distort cyclic voltammetry in battery electrode materials, tracing that distortion from its thermodynamic origin through its diagnostic and design consequences across silicon, olivine, spinel, and layered-oxide chemistries. Cyclic voltammetry (CV) is the diagnostic workhorse of battery electrochemistry; experimentalists read peak positions, heights, and shapes as fingerprints of thermodynamic state and reaction kinetics. What the standard interpretation omits is the mechanical condition of the electrode. Crystallographic dislocations inside cathode nanoparticles generate stress fields that couple directly into the electrochemical boundary condition, and the resulting shifts and distortions in the CV response can be misread as purely chemical or kinetic phenomena. This coupling operates across material classes. Voltage hysteresis in silicon anodes, anomalous plateau formation in Mn-substituted olivines, and voltage fade in lithium-rich layered oxides are each a manifestation of the same Butler-Volmer correction in a different host. The mechanistic framework rests on the Larché-Cahn formalism, in which dislocation-induced hydrostatic stress enters the chemical potential of Li intercalation and shifts the equilibrium insertion potential. When the partial molar volume is allowed to vary with lithium content rather than held fixed, the correction produces true distortion of CV peak shape rather than a mere rigid shift. Burgers vector orientation emerges as the controlling variable: one specific orientation raises the effective Li diffusivity extracted from Randles-Ševčík analysis by a factor of 3.3, a mechanical artifact that can be mistaken for genuine transport improvement. CV peak asymmetry, when interpreted through an anisotropic dislocation mechanics inversion, can identify the dominant dislocation character in an electrode without separate structural characterization. Defect engineering, meaning the deliberate introduction of dislocations of a chosen orientation, follows as a practical design strategy, provided the critical density threshold separating beneficial stress relief from crack incubation is not exceeded.