The present invention relates to a method for preparing an electroactive metal polyanion or a mixed metal polyanion comprising forming a slurry comprising a polymeric material, a solvent, a polyanion source or alkali metal polyanion source and at least one metal ion source; heating said slurry at a temperature and for a time sufficient to remove the solvent and form an essentially dried mixture; and heating said mixture at a temperature and for a time sufficient to produce an electroactive metal polyanion or electroactive mixed metal polyanion. In an alternative embodiment the present invention relates to a method for preparing a metal polyanion or a mixed metal polyanion which comprises mixing a polymeric material with a polyanion source or alternatively an alkali metal polyanion source and a source of at least one metal ion to produce a fine mixture and heating the mixture to a temperature higher than the melting point of the polymeric material, milling the resulting material and then heating the milled material. It is another object of the invention to provide electrochemically active materials produced by said methods. The electrochemically active materials so produced are useful in making electrodes and batteries.