TEM characterization of MnO2 cathode in an aqueous lithium secondary battery

The discharge characteristics of manganese dioxide cathode in the presence of small amounts (1, 3 and 5 wt. %) of titanium disulphide (TiS2) additive has been investigated in an alkaline cell using aqueous lithium hydroxide as the electrolyte. The incorporation of small amounts of TiS2 additives into manganese dioxide (MnO2) was found to improve the battery discharge capacity from 150 to 270 mAh/g. However, increasing the additive from 3 to 5 wt. % causes a decrease in the discharge capacity. Hence, the objective is to gain insight into the role of TiS2 in MnO2 and its mechanism. For this purpose, we have used transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS) and secondary ion mass spectrometry (SIMS). The valence state determination and the depth profile analysis of the discharged MnO2 were performed using EELS and SIMS techniques.