Ionites

Ionites are a class of crystalline materials studied in materials science that possess a rigid framework hosting mobile cations, giving them pronounced ionic conductivity. The term is used to describe solid electrolytes in which negatively charged frameworks trap the lattice while positively charged ions move through interconnected channels. Ionites derive their name from the word ion and the common mineral suffix -ite, reflecting their mineral-like crystal habit and ionic conduction.

Discovery and development: Ionites were first described in the context of solid-state ionics in the late 20th and early 21st centuries, during research into alternatives to liquid electrolytes for batteries. Since then, researchers have synthesized numerous variants, both in laboratory settings and from natural raw materials found in trace mineral deposits and certain silicate-rich rocks.

Structure and composition: Most Ionites feature a three-dimensional anionic framework built from metal–oxide or metal–silicate units, forming channels or cages that accommodate mobile cations such as Li+, Na+, K+, or Ag+. The exact structure varies by composition, with pore size and connectivity determining ion mobility and electrochemical stability.

Properties and applications: Ionites commonly exhibit high ionic conductivity at room or moderately elevated temperatures and a wide electrochemical stability window, making them attractive as solid-state electrolytes. They are studied for use in lithium- and sodium-based batteries, supercapacitors, and selective ion sensors. Synthesis methods include solid-state reactions, hydrothermal routes, and thin-film deposition.

See also: solid electrolyte, ion conductor, zeolite, perovskite oxide.