Electrochemical properties of a LiMn2O4 film in 1 M LiPF6/PC + EC solution was studied by means of the electrochemical quartz crystal microbalance (QCM) at an elevated temperature (50°C). The film preparation was conducted by an electrostatic spray deposition, which enabled us to obtain a uniform and dense film of LiMn2O4 on a QCM electrode at low temperature (400°C) to avoid the thermal damage of the quartz. During the galvanostatic charge-discharge experiment, the mass of electrode specimen increased, most likely due to the formation of a passivation film. If an as-prepared electrode was only immersed in the LiPF6 solution at 50°C, the mass of electrode decreased steadily, resulting eventually in extinction of the manganese film. Such manganese dissolution was attended by a shift of open circuit voltage from 3.8 to 4.3 V vs. Li, suggesting a formation for λ-MnO2 as an intermediate in the dissolution reaction.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry