Superionic conduction electrolyte through in situ structural transformation in electrochemical cell

High ionic conductivity at reduced temperatures may allow electrochemical cell applications to be efficiently scaled up. Herein, we introduce an approach that exploits electrode-electrode synergy and in situ structural transformation to increase the ionic conductivity of an electrolyte within the electrochemical cell. This transformation is based on the formation of a Li2TiO3-Li2CO3 heterostructure electrolyte via the combination of a TiO2 semiconductor precursor, polystyrene spheres as the soft skeleton, and the lithium-based electrode LiNi0.8Co0.15Al0.05O2. The unique surface and interface of the heterostructure electrolyte enable the formation of long-range ion transport channels that lower electrode impedance, resulting in a superior ionic conductivity of 0.23 S cm−1 at 550 °C and a high-power density of 1239 mW cm−2. Our general method to form superionic electrolytes shows potential in fuel cell technologies. Achieving high ionic conductivity at reduced temperatures is important for electrochemical cell scale-up. Here, a Li2TiO3-Li2CO3 heterostructure electrolyte was formed in situ within the electrochemical cell which shows superionic conductivity.