Electrochemical performance of calcium cobaltite nano-plates

The use of nanostructured materials in Li-ion batteries is desirable from the point of view of achieving enhanced performance, due to the shorter Li-ion diffusion distance and the small dimensional changes upon cycling. Herein, the nanocrystalline calcium cobaltite (Ca ₃Co ₄O ₉) powders were prepared by the Pechini process. The obtained nano-plate powders have a thickness of the order of 10-50 nm and a diameter of around 300 nm. We investigated the electrochemical properties of Ca ₃Co ₄O ₉ as a potential new anode material with high capacity for Li-ion batteries. In addition, the mechanism of Li reactivity was successfully explained using high resolution transmission electron microscopy. The full reduction of Ca ₃Co ₄O ₉ by lithium leads to the destruction of crystal structure and subsequent formation of a nanocomposite electrode containing Co, Li ₂O, CaO, and a polymeric layer. The inactive CaO matrix is expected to mitigate the aggregation of the Co nanoparticles on continued cycling, thereby improving the capacity retention.