The separator acts as a safety feature in LiBs. It acts as a physical barrier keeping the cathode and the anode apart. It prevents contact between the electrodes, which might lead to a short circuit. It only allows ions to pass freely through its internal microscopic holes which is essential for the functioning of the battery. Various separator materials used for liquid electrolyte-based Li-ion batteries have been reviewed in the following article . Synthetic membranes like polyethene (PE) and polypropylene (PP) are generally used as separators for LiBs.