| Transition metal compounds (typically oxides) are commonly used for battery cathode materials. Of the transition elements, both iron (Fe) and manganese (Mn) are relatively abundant, inexpensive, and non-toxic. For this reason iron and manganese compounds are of interest as safe, environmentally friendly materials to be incorporated in high performance batteries. Unfortunately some of the most promising iron and manganese compounds are known to exhibit less than ideal chemical stability, and they often engage in undesirable secondary reactions that diminish battery capacity.; This dissertation describes the use of sol-gel synthesized nanoparticulate coatings to stabilize cathode materials. SiO2 and TiO2 coatings are explored for BaFeO4 ferrate cathodes in primary batteries, while TiO2 and ZrO2 coatings are applied to LiMn 2O4 spinel cathodes in secondary batteries. The coatings are shown to enhance the stability and performance of batteries employing lithium-ion chemistries. These findings may benefit the lithium-ion industry, particularly as demand for batteries grows in response to the expanding consumer electronics and hybrid vehicle markets. |
