The sol-gel technique enables the production of LAGP particles at lower processing temperatures compared to sintering or glass crystallization. The typical precursor is a germanium organic compound, like germanium ethoxide , which is dissolved in an aqueous solution with stoichiometric amounts of the sources of lithium, phosphorus, and aluminium. The mixture is then heated and stirred. The sol-gel process starts after the addition of a gelation agent and the final material is obtained after subsequent heating steps aimed at eliminating water and at promoting the pyrolysis reaction, followed by calcination.
The sol-gel process requires the use of germanium organic precursors, which are more expensive compared to GeO.