Abstract
All-solid-state batteries (ASSBs) represent a promising alternative to lithium-ion batteries (LIBs), overcoming the flammability risks associated with organic electrolytes in LIBs. ASSBs employ non-flammable solid electrolytes, offering enhanced lifespan, capacity, and charging performance. The two main configurations of ASSBs are bulk-type, ideal for large-scale applications, and thin-film type, suitable for small devices and already commercialized with proven cycle and shelf life. However, bulk-type ASSBs present challenges in forming high-quality interfaces between the solid electrolyte and electrodes, resulting in increased interfacial resistance. Unlike previous research, this study focuses on the critical interface shape between composite anodes and electrolytes. It introduces the use of topology optimization to design these interfaces, providing a physics-based optimal design approach. First, the optimization problem for enhancing the efficiency of ASSBs is formulated by introducing a new objective function for ASSBs, which aims to reduce the computational cost and provide a good approximation to the original objective function. Then, the sensitivity for the formulated optimization problem is derived using the adjoint variable method. We confirm the validity of the derivation through comparison with numerical finite differences.
