New Insights into the Mechanism of Enhanced Performance of Li[Ni 0.8 Co 0.1 Mn 0.1 ]O 2 with a Polyacrylic Acid-Modified Binder

A binder is an important component in lithium-ion batteries and plays a significant role in maintaining the properties of active substances. Most studies in the field of binders have only focussed on physical properties such as bonding performance. Here, a polyacrylic acid-modified binder was designed and adapted to Li[Ni Co Mn ]O , which enhanced the electrochemical stability of Li[Ni Co Mn ]O from 30.2 to 66.6% (300 cycles at 1 C). We for the first time discovered that this was caused by a chemical reaction between polyacrylic acid and the residual lithium on the surface during the cycling, which formed a lithium propionic acid coating layer and maintained the stability of the layered structure.