Dry Processed Nickel-Rich Layered Transition Metal Oxide Cathode Electrode

Abstract

Lithium ion battery is a key driver for the proliferation of clean transportation. While its high energy density and operating life time are favorable, the overall cost is limiting widespread adoption. Since the first commercial lithium ion batteries produced by Sony in 1991 for consumer electronics, energy density and life time have gradually improved with the development of new electrode materials such as high capacity LiNixMnyCozO2, LiNi0.8Co0.15Al0.05O2 and silicon, and electrolyte additive such as vinylene carbonate1 and fluoroethylene carbonate2. Recently nickel-rich layered cathode and high capacity silicon anode have been incorporated into commercial lithium ion battery to further increase energy density. While electrode materials have advanced, electrode manufacturing process has largely remained the same, reaching a plateau in coating width, line speed, electrode energy density and production cost. To address these critical needs, Maxwell Technologies has developed a dry battery electrode coating technology with differentiating attributes. Maxwell’s unique solvent-free coating process used to commercialize ultracapacitors can be adapted to produce electrodes using current state-of-the-art lithium ion battery chemistries and advanced materials3-5 with advantages over conventional wet coating process. The benefits are lower CO2 emission, lower capex and opex cost, improved energy density and the ability to process moisture sensitive or reactive materials. To demonstrate these attributes, we have advanced our dry electrode process development using nickel-rich layered cathode materials to improve energy density, increase cycle life and reduce cell manufacturing cost. We have produced dry electrodes using LiNi0.6Mn0.2Co0.2O2, LiNi0.8Mn0.1Co0.1O2 and LiNi0.8Co0.15Al0.05O2 in roll-to-roll format and characterized their electrochemical performances in small and large capacity pouch cells. Dry process demonstration for prelithiated materials has also been established. This paper will report the physical properties of nickel-rich layered dry cathode film produced at the lab and pilot production level and their electrochemical performance with coating loading of 30-40mg/cm2 per coating side, which is significantly heavier than a typical wet cast electrode in the range of 20-24mg/cm2 per coating side in commercial high energy 18650 cell.