Physicochemical properties of Na x CoO2 as a cathode for solid state sodium battery

Abstract: An intercalation compound with composition Na0.7CoO2 has been synthesized through different preparative techniques such as solid state reaction, ball milling and sol gel techniques. The investigation reveals that the cathode material with an average particle size of about 500nm of uniform morphology can be synthesized through sol gel technique. Further, this synthesis technique improves the stoichiometry of the sodium content significantly. The electrical resistivity of these cathode materials is found to be in the range of 4 to 12mΩ-cm at 300K. It has been observed that, the resistivity of the cathode material increases with increase in sodium content. The electrochemical cells with the configuration Na | [wt.% 0.3 PEO-0.7 PEG]6:NaPO3 |composite cathode material, have shown an open circuit voltage (OCV) value of 2.7V. The (OCV) of the cells with the cathode prepared by sol–gel and ball milling route has shown a plateau region of about 40h, when compared to the plateau region of 10h for the battery with the cathode prepared by solid state reaction. The reduction in the particle size of the cathode material has improved the stability of the electrode electrolyte interface and thereby discharges characteristics. [Copyright &y& Elsevier]