Synthesis and characterization (Li۴Ti۵O۱۲, LTO) and investigation of its electrochemical properties as anodes in lithium-ion batteries using PMMA and PVDF polymer binders

Lithium-ion batteries with spinel Li۴Ti۵O۱۲ negative electrodes have been recognized as a promising candidate for the future energy storage system, because of their remarkable rate capability and cycle life performance and inherent safety. Polymer binder as a critical component in electrodes of batteries improve the cell performance. In this study, LTO powder has been synthesized by solid-state reaction. Morphology and structure of LTO were investigatedby X-ray diffraction, scanning electron microscopy and EDX analysis. The LTO electrodes were obtained by different binders (PVDF, PMMA, PVDF-PMMA) and were tested in half-cell.Electrochemical characterization was performed by galvanostatic charge-discharge experiments and impedance spectroscopy. The LTO electrode with the optimized composite binder exhibits enhanced ionic conductivity, increased flexibility of the binder matrix and significantly improved electrochemical properties compared to that with pure PVDF binder. At a very high discharge rate of ۵C, the LTO electrode with (PVDF-PMMA, ۳-۲ Wt%) composite binder still retains ۹۵% capacity after ۱۰۰ cycles, while the electrode based on PVDF binder only delivers ۱۵%. Additionally, the LTO electrode with (PVDF-PMMA, ۳-۲ Wt%) composite binder showed a much enhanced reversible capacity of ۱۷۸ mAhg-۱ and first coulombic efficiency is ۸۶%. These results enable us to get deep insight in to the rational design of blended with interior synergistic effect for high-rate and long-life Li-ion battery anodes.