Cellulose and its derivatives for lithium ion battery separators: A review on the processing methods and properties

There is a growing demand for lithium ion batteries (LIBs) fabricated with environmentally-friendly materials to transition toward a more sustainable society based on a circular economy. Battery separator, typically a porous petroleum-polymer, plays a pivotal role as it serves to efficiently transfer ions between electrodes while preventing electrical short-circuits. To reduce our dependence on fossil resources, cellulose and its derivatives are being used as sustainable battery separators thanks to its easily controllable porosity, suitable mechanical and thermal properties, non-toxicity and inherent hydrophilicity. Here we first present the structure, physico-chemical properties and various types of cellulose derivatives, as well as the different manufacturing approaches to obtain porous cellulose membranes. Further, the most recent developments in the field of cellulose and its derivates for lithium ion battery separators and solid polymer electrolytes are discussed. Finally, the main issues and properties to be improved in the near future concerning cellulosic separators are shown.