Electrical double layer in solid electrolytes

Electrical double layers at interfaces are critical to the performance of electrochemical energy storage and conversion devices. We present a general theoretical framework for the electrical double layer in solid electrolytes, where mobile point defects serve as charge carriers. Our model accurately treats both the core and space-charge layers in solid electrolytes across both dilute and concentrated regimes [1]. Our model incorporates the variation in defect formation energy near interfaces and defect-defect interactions, maintaining consistency with first-principles simulations of solid electrolyte interfaces [2]. Simulations based on this framework demonstrate that the core layer has a significant impact on the resulting potential and defect concentration profiles and consequently governs the emergent capacitance and ion conductivity. Our model serves as a useful tool for the rational design of interfaces for next-generation solid-state electrochemical devices.

 

[1] Z. Ahmad, Journal of Materials Chemistry A 13, 25599 (2025).

[2] M. S. R. Limon and Z. Ahmad, ACS Applied Materials & Interfaces 16, 50948 (2024).