Electrochemical and Thermal Interplay in Blended Cathodes for All Solid‐State Batteries

We investigate composite solid state blended cathodes composed of lithium iron phosphate (LFP), nickel cobalt manganese oxide (NMC), and halide solid electrolyte for application in all solid state batteries (ASSBs). Electrochemical characterization indicates that the blended cathode integrates the high rate capability of LFP with the high specific capacity of NMC. Synchrotron X‐ray diffraction (XRD) techniques, including spatially resolved operando micro‐diffraction, reveal asymmetric charge distribution, and lithiation gradients across the cathode depth during electrochemical cycling. Complementary thermal modeling demonstrates that the blended cathode generates less heat than pure NMC, thereby enhancing thermal stability. These results highlight the potential of blended cathodes to achieve an optimal balance between performance and safety in ASSBs and provide valuable insights for the design of microstructures for next‐generation solid state battery systems.