Synthesis of sulfide cathodic materials and study of their physicochemical properties and electrochemical activity

A relationship has been ascertained between the conditions of synthesis, physicochemical properties and electrochemical activity of sulfide cathodic materials (TiS2, V2S2, MoS3) in lithium batteries with an aprotic electrolyte. The existence of two forms of titanium disulfide has been shown for the first time, a ‘soft’ and ‘hard’ form (TiS2(s) and TiS2(h)) that differ essentially in their structure, conductivity, electrochemical activity and mechanism of intercalation. TiS2(s) synthesized under non-stationary conditions with a considerable disorderliness has greater specific capacity (210 mAh/g) and better lithium transport properties than TiS2(h) synthesized under long stationary conditions. It has been shown that the effectiveness of solid-phase cathodic materials in lithium batteries is caused by their macro- and microstructure and depends on their preparation conditions, the stoichiometry of active cathodic substances is not the basic criterion. The other cathodic materials obtained by the methods of non-stationary synthesis also possess extremely high specific properties: MoS3: not, vert, similar 400 mAh/g and V2S2: 240–260 mAh/g.