A study on LiFePO₄/graphite cells with built-in Li₄Ti₅O₁₂ reference electrodes

In this work, based on the superior electrochemical stability of Li₄Ti₅O₁₂ (LTO) electrodes, LiFePO₄ (LFP)/graphite cells with built-in LTO electrodes as reference electrodes were designed and fabricated. The characteristics of the LTO reference electrodes in the fabricated lithium-ion cells were measured and discussed. The experimental data demonstrated that the LTO built-in reference electrodes were simple to prepare and were feasible options for long-term in situ monitoring of the development of potentials and other electrochemical parameters, such as the Li⁺ diffusion coefficient (D_Li) and electrochemical impedance spectroscopy (EIS) information, for both anodes and cathodes. Moreover, it is believed that the adoption of LTO as a reference electrode could be of great significance for long-term monitoring of the charge and discharge behavior of individual electrodes in other kinds of lithium-ion cells.