Suppression of Dendrites in Metal-Anode Batteries by the Soret and Seebeck Effects

Intentionally applied external thermal gradients are a proposed strategy to mitigate dendrite growth on lithium–metal anodes, improving battery safety and lifetime. Small temperature differences produce large thermal gradients across the cell due to the thinness of the separator, which can cause thermodiffusion in the electrolyte. We include ionic Soret and Seebeck effects in continuum models of interfacial evolution to study how thermodiffusion affects dendrite growth. We demonstrate that thermal gradients promote anode stability through preferential lithium deposition at dendrite roots instead of at dendrite tips. This preference significantly delays dendrite growth, and we identify a critical thermal gradient, beyond which dendrites are fully suppressed. These predictions qualitatively agree with the experimental literature and explain why dendrite suppression by thermal gradients is sensitive to the applied current density. Growth can also be accelerated unintentionally by the thermal gradient, which provides crucial insight for the design of electrolytes, cell geometries, and thermal management systems.