Squaric acid-based polymers and their use in electrode materials and/or electrolyte compositions, as well as their production processes are described herein. Also described are electrode materials, electrodes, electrolyte compositions, electrochemical cells, electrochemical accumulators, and optoelectronic devices comprising the polymers and their uses.

Provided is a method for producing an aromatic polyether, comprising reacting 4,4-dichlorobenzophenone and hydroquinone in the presence of a potassium carbonate satisfying at least one of the following conditions (A) and (B): (A) the potassium carbonate has a bulk density of 1.2 g/ml or less; and (B) an average particle diameter D (m) and a specific surface area S (m.sup.2/g) of the potassium carbonate satisfy D/S600.

A method for synthesizing polyphenylene ether. The method involves conducting a condensation reaction of polymer monomers and oxygen under the action of a catalyst to form polyphenylene ether. By controlling the addition rate and amount of the catalyst during the reaction process, the molecular weight and molecular weight distribution of the polyphenylene ether can be regulated. Using the synthesis method of the present invention, the molecular weight and molecular weight distribution of the polyphenylene ether product can be effectively controlled by managing the addition rate and amount of the catalyst.