Thermal Modulation of Electrodeposition Stability in Sodium Metal Electrodes.

Sodium metal batteries (SMBs) have gained interest due to the high natural abundance and lower cost of sodium (Na) compared to lithium (Li), making them a promising alternative to conventional Li-based battery systems. However, a key challenge toward the commercial viability of SMBs lies in mitigating uneven electrodeposition and dendrite growth, stemming from inherent interfacial instabilities during Na plating. This work explores how electrodeposition stability in SMBs is governed by thermal conditions, which directly affect ionic transport and interfacial reaction kinetics. A range of thermal environments are explored using a phase-field modeling (PFM) framework, with a particular emphasis on the influence of temperature gradient-induced thermodiffusion (Soret effect) on deposition dynamics. A quantitative analysis of dendrite growth under varying thermal conditions is conducted to identify regimes that promote stable plating behavior. It is found that operational temperature serves as a strong modulator of plating instability by simultaneously influencing reaction kinetics and ion transport, and thermodiffusion under imposed temperature gradients further redistributes ionic flux and alters deposition morphology. This work provides new insights into the role of thermal landscapes in dictating interface evolution during Na metal plating and offers design guidelines for leveraging thermal conditions to enhance deposition stability in Na metal electrodes.