A mixed ion–electron conducting material for all-solid-state batteries

All-solid-state batteries are next-generation energy storage devices that replace the flammable liquid electrolyte in conventional lithium-ion batteries with solid materials to improve safety, energy density, and lifespan. However, their development is limited by the lack of materials capable of simultaneously conducting ions and electrons. 

Alexandru Vlad (WEL Research Institute – UCLouvain) and his collaborators investigated metal–organic frameworks (MOFs), porous materials composed of metal nodes linked by organic ligands, which offer great chemical tunability but had not previously exhibited this dual conductivity. The researchers designed a single-phase MOF with mixed ion–electron conduction using a “cation-rich” reduction strategy, strongly enriching the material in Li⁺ ions while generating electronic carriers. Its conduction properties were experimentally characterised at room temperature, and the MOF was integrated into a proof-of-concept all-solid-state battery.

This work provides the first demonstration of a single-phase MOF exhibiting mixed conduction and highlights its potential for application in solid-state electrochemical devices.

Reference: Apostol et al, A single-phase mixed ion-electron conducting metal−organic framework, J Am Chem Soc (2026) doi:10.1021/jacs.5c18105