Electrochemical quartz crystal microbalance measurement of a Li₄Ti₅O₁₂ composite electrode in a carbonate electrolyte

Abstract Electrochemical quartz crystal microbalance (EQCM) measurement is conducted with a Li₄Ti₅O₁₂ (lithium titanium oxide, LTO)-coated quartz crystal electrode in a carbonate electrolyte (ethylene carbonate + dimethyl carbonate; 50: 50 vol%) containing 1 M LiPF₆. In-situ monitoring of the mass change during the charge and discharge of the LTO electrode can be achieved quantitatively because of the "zero-strain" property of LTO with Li⁺ insertion and the probably low reactivity between LTO and the electrolyte. The local changes of viscosity and density of the electrolyte contacting the LTO electrode are detected via the resonance resistance of the quartz crystal electrode, suggesting the local concentrations of Li⁺ and counter anion changed significantly during insertion and extraction of Li⁺ in the organic electrolyte.