Harnessing Electrochemical‐Mechanical Couplings to Improve the Reliability of Solid‐State Batteries

One key barrier to using lithium‐metal anode batteries is that metal dendrites can penetrate solid electrolytes, causing short‐circuits and battery failures. It is established that this failure is likely caused by crack propagation due to electrodeposition‐induced stresses from lithium metal. This study explores ways to harness these electrochemical‐mechanical couplings to control dendrite growth and improve battery reliability using a phase‐field model and targeted fracture experiments. The results show that dendrite growth can be effectively mitigated by applying mechanical stresses or tailoring the material's fracture toughness. This study also outlines the requirements for compressive stress to halt or deflect dendrites as a function of the overpotential and discusses the role of microstructure in this process. Lithium dendrite penetration in solid‐state batteries can be arrested or deflected by applying lateral mechanical stresses or tailoring the material's fracture toughness ahead of the crack tip, taking advantage of the electrochemical‐mechanical couplings driving crack propagation.