Electron Beam Irradiated Li4Ti5O12 Electrode for High Rate Lithium Ion Batteries

In this study, we demonstrate that the rate capability of the Li₄Ti₅O₁₂ (LTO)-based anode in a lithium ion battery can be improved by electron beam (EB) irradiation, without the need for complicated synthesis procedures. In order to achieve this, we investigated the effect of EB irradiation on rate capability by EB irradiation i) of an electrode coated with a LTO, PVDF, and super P slurry mixture and, also, ii) of individual component powders. In the case of the EB-irradiated electrode, the LTO, PVDF, and super P were irradiated together in a single mixture. In contrast, the individually EB-irradiated component powders were mixed with other non-irradiated components, followed by coating of the mixture on Al foil. The EB-irradiated electrode shows an enhanced rate capability, while retaining a discharge capacity of ~80 mAh g^-1 at the 20 C-rate. The effect of the EB irradiation on the properties of each component is examined by characterization of the EB-irradiated materials using X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, charge-discharge analysis, and electrochemical impedance spectroscopy. As a result, the enhanced rate capability was attributed to the changes in the properties of the LTO and PVDF due to the EB irradiation. The electronic conductivity of LTO was enhanced by Ti³⁺ formation, while the PVDF mechanical strength and interaction with other components may have been improved by crosslinking, and unsaturated and hydrophilic structure formation under EB irradiation. Because the EB irradiation process is already well established in the industrial process, it could easily be applied to the mass production of LTO-based electrodes with improved charge-discharge properties.