Laser micro structuring of composite Li(Ni0.6Mn0.2Co0.2)O2 cathode layersfor lithium-ion batteries

Abstract

Lithium-ion batteries (LIB) using lithium nickel manganese cobalt oxide (Li(Nu/3Mn1/3Co1/3)O2, NMC-111) as cathode material have already become one of the most important types of mobile power sources due to their high gravimetric and volumetric capacity. Nevertheless, the automotive industry needs batteries with a further improved energy density to develop electric vehicles (EV) with comparable or even higher range than automobiles with ICE (Internal combustion engine). One approach to enhance the energy density is to increase the nickel content of the NMC cathode material. Therefore, NMC-622 cathodes were produced via tape casting containing 80 wt% of active material with a film thickness of 54 μm. The specific capacities were measured using galvanostatic measurements at different charging/discharging currents for cells with structured and unstructured electrodes. An improved lithium-ion diffusion kinetic due to an increased active surface area could be achieved by laser-assisted generation of three-dimensional architectures. Ultrafast laser ablation was used in order to avoid a thermal-induced damage of the active material. It could be shown that laser structuring of electrode material leads to a significant improvement of the electrochemical performance, especially at high charging and discharging currents.