Electrochemical-mechanical coupling mechanism of lithium deposition behavior in three-dimensional frameworks and conductivity engineering regulation

Lithium metal anodes are regarded as promising candidates for next-generation high-energy batteries owing to their exceptionally high theoretical energy density. However, their practical application is hindered by uncontrolled lithium deposition, large volume fluctuations, and instability of the SEI. Based on the electrochemical-mechanical-SEI multiphysics coupling model, we elucidated the evolution of lithium deposition in three-dimensional space and the mechanisms of morphological instability. From the perspective of spatial conductivity engineering, we compared three framework types: in the all-conductive framework, a large amount of lithium accumulates as dendrites in the top dangerous region; in the top-insulated framework, the top dendrite region is significantly reduced, and the effective deposition area increases; while in the fully-insulated framework, the effective deposition area decreases slightly, but it almost eliminates top dangerous deposition, and homogenizes SEI thickness and stress. At the same time, in-situ expansion and ultrasonic imaging experiments confirmed that the insulated framework can suppress volume expansion and the accumulation of interfacial defects. This study elucidated the multiphysics coupling failure mechanism of lithium deposition in 3D frameworks, and proposed a current collector framework optimization strategy based on conductivity engineering, thereby providing theoretical and experimental guidance for constructing highly stable lithium metal anodes.