Low-temperature synthesis process of making MgzMxOy, where M is Mn, V or Fe, for manufacture of electrode materials for group II cation-based batteries

A method of making a Mg-deficient metal oxide composition comprising MgzMxOy, wherein M is a metal selected from the group consisting of V, Mn, and Fe;

• z/(x+y+z) is the mole fraction of Mg in the composition;
• x/(x+y+z) is the mole fraction of metal M in the composition;
• and y/(x+y+z) is the mole fraction of O in the composition, each of x and y and z being greater than zero, the method comprising:
• a direct, low-temperature, sol-gel synthesis process, the process including:
• isolating a precursor comprising a stoichiometric Mg-containing metal oxide as a crystalline material;
• dissolving the precursor in water at a dissolution temperature between 20° C. and 60° C.;
• and
• treating the dissolved precursor at said dissolution temperature by ion exchange to obtain the Mg-deficient metal oxide sol composition comprising MgzMxOy.