Water‐Based Process to the Preparation of Crack‐Free Thick Films of Li‐Rich‐Layered Oxide Cathode for High‐Performance Pouch Cells

Owning to the low cost and eco‐friendliness, water‐based method for the fabrication of electrode films is attractive for Li‐ion battery industry. Several drawbacks such as sluggish kinetics, crack, and nonuniformity should be overcome before its practical application for anode and cathode electrodes. Herein, a modified water‐based method based on carboxymethyl cellulose/styrene‐butadiene rubber as binder has been established for the successful fabrication of Li‐rich layered oxide (LLO) electrode films without crack. As the additives of aqueous slurry, acetic acid (HAc) can inhibit the corrosion of Al foil, while ethylene carbonate can reduce the surface tension of slurry and alleviate the capillary pressure during drying. Thick LLO electrode films with a high mass loading up to 40 mg cm −2 (area capacity > 9 mAh cm −2 ) can be achieved. Such films have good peeling strength and flexibility that can avoid the removal of active layers from Al foils under the practical operations. Multilayer pouch cells consisted of graphite anode and LLO cathode by the modified water‐based method display excellent electrochemical performances. A 2.4 Ah pouch cell can deliver an energy density of 240 Wh kg −1 and show a high capacity retention of 90.5% after 500 cycles at C/2.