Cellulose Membrane Coated with Polyacrylate as Lithium-Ion Battery Separator for Improved Operational Stability

As the widespread application of lithium-ion batteries and growing environmental protection requirements, it is of great research significance and commercial value to develop high-performance separator materials with both sustainability and economy. The aqueous polyacrylate dispersion (APD) is synthesized and applied to a cellulose-based membrane (CM) as an improved lithium-ion battery separator in this work. It is confirmed by structural characterization and morphological observation that APD is successfully coated onto the surface of CM to form a functional protective layer. The optimized CM-APD separator provides greater dimensional, thermal, and chemical stability, which is evidenced by lower dimensional shrinkage and less mass loss at high temperatures as well as a superior electrochemical stability window (5.29 V), in addition to excellent electrolyte uptake (154%) and ionic conductivity (2.31 mS·cm–1). Besides, owing to enhanced electrochemical stability and interfacial compatibility by the functional groups in the APD, batteries with the CM-APD separator show significantly better operational stability and specific capacity compared to original CM and commercial polypropylene (PP) separators. Therefore, the improved cellulose separator CM-APD provides valuable insights for the development of high-performance lithium-ion batteries that satisfy both environmental friendliness and economic requirements.