Thermal and electrochemical stability of cathode materials in solid polymer electrolyte

• Published in: Journal of power sources Vol. 92; no. 1; pp. 234 - 243
• Main Authors: Xia, Yongyao, Fujieda, Takuya, Tatsumi, Kuniaki, Prosini, Pier Paolo, Sakai, Tetsuo
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 2001; Elsevier Sequoia
• Subjects: Applied sciences; Cathode materials; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Lithium batteries; Polymer electrolyte; Thermal stability; Lithium batteries; Polymer electrolyte; Cathode materials; Thermal stability; Cobalt oxide; Differential scanning calorimetry; Cathode; Polymer solid electrolyte; Secondary cell; Electrode material; X ray diffraction; Manganese oxides; Battery; Vanadium oxide; Lithium oxide; Thermal analysis; Nickel oxide
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/S0378-7753(00)00533-4

Thermal stability of cathode materials, including LiCoO 2, LiNiO 2, LiMn 2O 4, V 2O 5, V 6O 13, and Li x MnO 2 in contact with poly(ethylene oxide) (PEO) based solid polymer electrolyte was systemically investigated by means of thermal analysis in combination with X-ray diffraction technique (XRD). The differential scanning calorimetry (DSC) analysis showed significant exothermic reaction of both LiNiO 2 and LiCoO 2 in contact with the polymer electrolyte. LiMn 2O 4 was less reactive compared with LiNiO 2 and LiCoO 2. V 2O 5, V 6O 13, and Li x MnO 2 were also found less reactive, especially in their discharge states. The XRD results indicated that the thermal decomposition products of the cathode material were the low valance metal oxides, suggesting the exothermic reaction was an oxidation reaction of the polymer electrolyte with active material. The decomposition temperature is somehow dependent on the potential of the cathode active materials. Cyclic voltammetry reveals that PEO based solid polymer electrolyte is stable up to 5.0 V versus Li/Li + at a blocking electrode, whereas it decomposes at ca 3.8 V when contacted with a carbon composite electrode.