High-Spatial-Resolution Quantitative Chemomechanical Mapping of Organic Composite Cathodes for Sulfide-Based Solid-State Batteries

Understanding the chemomechanical behaviors of electrodes, particularly at electrode/electrolyte interfaces, is critical for improving the performance of all-solid-state batteries. However, due to the instability of electrolyte materials under ambient conditions, such characterizations are challenging, particularly for sulfide-based all-solid-state batteries. Herein, by combining time-of-flight secondary-ion mass spectroscopy (ToF-SIMS) and in-SEM nanoindentation measurements, a systematic quantitative investigation of the chemomechanical behaviors of pyrene-4,5,9,10-tetraone (PTO)/Li6PS5Cl composite cathodes is carried out. Chemical and quantitative mechanical information on the composite cathode was collected with high spatial resolution after developing and implementing an air-free characterization protocol. By directly connecting the Young’s modulus and hardness with the Li distribution in the composite cathode, a comprehensive chemomechanical mapping of the PTO/Li6PS5Cl composite cathode has been established. This work improves our knowledge of the critical chemomechanical phenomena that occur at the cathode/electrolyte interfaces in all-solid-state batteries.