Electrostatic dry coating of cathode materials for Li ion battery

Abstract

Organic solvents are widely used in wet coating for manufacturing Li ion batteries. This study focused on switching to environmentally benign solvent-free process, and examined a possibility of electrostatic dry coating (EDC) of cathode materials which are generally composed of active oxides, conductive and binder additives. Firstly, the composite particles containing the three components were prepared by dry mechanical treatment, and then EDC experiment was performed for the composite particles. Interestingly, the composite particles could be tribo-charged enough for electrostatic deposition on an earthed Al foil in air, with relatively high deposition rate. The as-deposited film was further dry-pressed to increase the film density (3×103kg/ m3). A half cell was assembled using the pressed film as cathode electrode, and it was demonstrated that the initial charge-discharge characteristics were comparable to those obtained for wet-coated films. The results obtained indicate that there are some opportunities for the practical implementation of the EDC method for manufacturing functional composite films.