The influence of different pre-treatments of current collectors and variation of the binders on the performance of Li4Ti5O12 anodes for lithium ion batteries

In order to optimize the electron transfer between the Li4Ti5O12-based active mass and the current collector, the surface of aluminum foil was modified either by alkaline etching or by a carbon coating. The as-modified aluminum foils were coated with an active mass of Li4Ti5O12 mixed with polyvinylidene fluoride, sodium carboxymethyl cellulose, or polyacrylic acid as binders. Untreated aluminum and copper foils served as reference current collectors. The corrosion reactions of aluminum foil with the applied binder solutions were studied and the electrode structure has been analyzed, depending on the binder. Finally, the electrochemical performance of the prepared electrodes was investigated. Based on these measurements, conclusions concerning the electrical contact between the different current collectors and the active masses were drawn. The energy density of the Li4Ti5O12 electrodes cast on carbon-coated aluminum foils was significantly increased, compared to the corresponding electrodes with a copper current collector.