Electrochemical-mechanical regulation of lithium deposition morphology in lithium metal batteries

Lithium (Li) metal batteries offer exceptionally high energy density but their practical application is severely constrained by dendritic growth at the Li metal anode. Applying stack pressure has emerged as an effective strategy to mitigate dendrite formation; however, the underlying mechanisms governing the coupling between electrochemical deposition and mechanically induced deformation remain insufficiently understood, leaving optimal pressure conditions across different electrolytes largely determined by trial and error. Here, we develop an electro-chemo-mechanical model, supported by experimental validations, to elucidate how electrolyte properties and stack pressure jointly regulate Li deposition morphology. We show that dendrite-favorable electrolytes (e.g., low Li⁺ diffusivity) promote irregular Li nucleation and growth, which concentrate local stresses under pressure and thereby undergo marked morphology improvement through pressure-induced creep. By contrast, electrolytes with inherently uniform deposition exhibit limited sensitivity to stack pressure. These findings establish a mechanistic framework for the competitive regulation of Li morphology by electrolyte chemistry and stack pressure, offering design principles for uniform Li plating in high-performance Li metal batteries.