The effect of polyacrylic Acid (PAA) binder molecular weight on the performance of alumina-coated polyolefin separator for lithium-ion batteries (LIBs)

Abstract

LIBs have been widely used for electronics and electric vehicles (EVs). Apart from the electrochemically active electrodes, separator also plays an important role in the battery performance. Due to the low electrolyte uptake and low thermal stability of commercial polyolefin membrane separators, ceramic-coated separators have attracted tremendous attentions. However, the commonly used non-aqueous polymer binders have a low binding strength and cause environmental pollution. In this work, aqueous PAA was used as the binder for alumina coating. By comparing two PAA binders with contrasting molecular weights (MW), we observed a better thermal stability and ion redistribution capability in the coated separator with high MW PAA binder. We concluded this work by proposing possible solutions to improve the structural integrity of the coating.