Universal superionic conduction via solid dissociation of salts in van der Waals materials

Conventional strategies for designing inorganic solid-state electrolytes, typically via doping superionic lattices, are constrained by dopant–lattice compatibility. Here we propose solid dissociation in which halide van der Waals materials act as solid solvents to dissolve salts, forming amorphous ion-conductive solids. Using this approach, we discover 73 materials, with 40 exhibiting ionic conductivities exceeding 10−3 S cm−1, conducting Li+, Na+, Ag+ and Cu+. We analyse atomic-scale interactions between solvents and salts, uncovering dynamic structural rearrangements that enable solid dissociation. Across diverse solvent–salt pairs, consistent ionic environments emerge, revealing universal mechanisms governing ion transport in this system. Analogous to the compositional tuning of liquid electrolytes, solid dissociation allows targeted engineering of solid-state electrolytes for specific application conditions. Prototype electrolytes have been developed for fast-charging cells, low-temperature cells and 4.8-V high-voltage cells, and demonstrate enhanced dry-room stability and cost advantages. Solid dissociation offers a versatile platform for advancing next generation solid-state electrolytes. Conventional solid-state electrolyte design is limited by dopant–lattice compatibility. This work introduces solid dissociation, using halide van der Waals materials to dissolve salts and create amorphous conductors with high ionic conductivity and potential for use in devices.