Engineering the micro/nano structure of Ca3Co4O9 anode material for lithium-ion batteries

Misfit-layered Ca3Co4O9 thermoelectric materials have attracted considerable attention as anodes for lithium-ion batteries due to high rate capability, structural stability, and chemical stability. The micro/nano-structures Ca3Co4O9 anode materials were prepared respectively by co-precipitation and molten salt method. The effect of different dimensions on the electrochemical properties was systematically investigated. It can be seen that the zero-dimensional (0D) polyhedron Ca3Co4O9 anode material exhibits high specific capacity and cycling stability at different multiplicities of lithium insertion/extraction rates, respectively. It maintained a high capacity of 316.3 mAh/g at the 100th cycle, corresponding to the Coulombic efficiency of over 95% during the discharge/charge process. The excellent electrochemical properties were attributed to the large specific surface area and channels for the intercalation of Li+. More active surface sites are provided, facilitating lithium ions' embedding/de-embedding reaction. The micro/nanostructures provide shorter ion and electron transport paths, which reduces the resistance of the electrode materials and facilitates high-rate charging and discharging, in addition to providing better mechanical stability and ion diffusion channels, which help to mitigate the volume expansion effect and improve cycling stability. This work suggests that engineering the micro/nanostructures of Ca3Co4O9 anode material can broaden the application of anode materials for high-performance lithium-ion batteries.