Highly Elastic Binder for Improved Cyclability of Nickel-Rich Layered Cathode Materials in Lithium-Ion Batteries

Nickel-rich layered cathode materials are predominantly used for lithium-ion batteries intended for electric vehicles owing to their high specific capacities and minimal use of high-cost cobalt. The intrinsic drawbacks of nickel-rich layered cathode materials with regard to cycle life and safety have largely been addressed by doping and by applying surface coatings. Here, it is reported that a highly elastic binder, namely spandex, can overcome the problems of nickel-rich layered cathode materials and improve their electrochemical properties drastically. The high elasticity of spandex allows it to uniformly coat LiNi_0.8Co_0.1Mn_0.1O₂ particles via shear force during slurry mixing to protect the particles from undesired interfacial reactions during cycling. The uniform coating of spandex, together with its hydrogen bonding interaction with LiNi_0.8Co_0.1Mn_0.1O₂, leads to enhanced particle-to-particle interaction, which has multiple advantages, such as high loading capability, superior rate and cycling performance, and low binder content. This study highlights the promise of elastic binders to meet the ever-challenging criteria with respect to nickel-rich cathode materials in cells targeting electric vehicles.