Abstract ▼ AI-Helper

Even though carbonaceous material has been used as the anode active material for lithium ion battery, this battery shows low charge/discharge rate because of its layered-structure. On the other hand, Li4Ti5O12 can be a promising anode material for high rate battery owing to its 3-dimensional spinel ...

Even though carbonaceous material has been used as the anode active material for lithium ion battery, this battery shows low charge/discharge rate because of its layered-structure. On the other hand, Li4Ti5O12 can be a promising anode material for high rate battery owing to its 3-dimensional spinel structure along with the little volumetric change during lithium ion intercalation and de-intercalation processes. However, Li4Ti5O12 shows barriers for commercial application, such as low electrical conductivity and theoretical capacity. In order to understand the physical properties associated with the solid-state synthesis of Li4Ti5O12 and, if possible, to mitigate these barriers, Li4Ti5O12 was synthesized by a solid-state reaction between Li2CO3 and anatase TiO2 as starting materials. Starting materials were milled by high energy milling and heat treated at 800°C for 3h in air with a heating rate of 5°C/min. Synthesized Li4Ti5O12 was evaluated by SEM, XRD and TEM. Assembled-cell after screen printing was evaluated by galvanostatic charge-discharge measurements. In this study, 2 main questions were tried to be answered: 1) whether the electrical conductivity could be enhanced by the incorporation of MWCNT and 2) whether the volumetric capacity could be increased by the spray drying for the starting materials. To elucidate the first question, MWCNT was added as a conductive material with the starting materials followed by the solid-state synthesis of Li4Ti5O12. Even though CNT is well-known for its high conductivity, the Li4Ti5O12 synthesized with MWCNT did not show any significant difference in the increase of electrical conductivity and electro-chemical property. For the second question, to improve the capacity and rate capability of lithium ion battery, high energy milling and spray drying for the starting materials were performed before heat treatment. It was found that these treatments were very effective to get a fine pure Li4Ti5O12 due to the decreased solid-state diffusion path and enhanced contact area among the starting materials. Moreover, the spray drying was found to be very effective in fabricating the fine spherical Li4Ti5O12 which shows high specific capacity and fast charging rate.