Electrophoretic Deposition of Out-of-Plane Oriented Active Material for Lithium-Ion Batteries

The performance of secondary batteries, of which the lithium-ion battery is one of the most well known, depends not only on the active electrode materials but also on the electrode architecture. In particular, the reduction in electrode tortuosity is expected to enable batteries with high active material utilization and fast charging and discharging capabilities. Herein, it is shown how electrophoretic deposition can be used to produce electrodes comprising hybrid particles of cobalt(II,III) oxide-coated rutile-mica oriented in an out-of-plane fashion. Key to this process is a sacrificial anode which leads to charging of the flake-shaped particles and formation of a holding layer cementing them perpendicular to the substrate. Moreover, the electrochemical performance of lithium-ion battery anodes with out-of-plane and in-plane oriented architectures is compared. The out-of-plane orientation of the flake-like particles results in better utilization of active material, lower charge-transfer impedance, and faster ion diffusion. Moreover, for a range of charge/discharge rates, the specific capacity is over three times higher in comparison to an electrode with the same material oriented in an in-plane architecture. The approach to electrode structuring is both facile and scalable and can be readily applied in the future to produce other electrochemical energy storage device electrodes.