Ex-situ study on the structure changes of Li4Ti5O12-based anode materials under different lithium insertion amounts

Abstract

In view of the decreased electrochemical performance of Li4Ti5O12 (LTO)-based batteries coming from the catalytic activity of LTO-based anode, this article focuses on the use of ex-situ methods to study the structure, oxygen vacancy, hydroxyl groups, Ti valence and photoluminescence spectrum of LTO-based materials under different charge and discharge conditions to reveal the source of the catalytic activity. The results show that as the amount of lithium intercalation increases, the oxygen vacancy concentration decreases, but the presence of trivalent titanium and hydroxyl groups leads to the separation of electrons and holes in the electrode material, which may be one of the reasons for the catalytic activity. Under the same amount of lithium insertion, the Li4Ti5O12-rutile TiO2 (LR) sample produces less separation of electrons and holes, so the catalytic activity of LR is lower than that of LTO. LR anode shows a better electrochemical performance than LTO anode.