NKK Cellulose Roll (TF4030, TF4425, TF4530) as Aqueous Supercapacitor and Battery Separator, CASBSC

Cellulose separators are highly valued as a sustainable, high-performance alternative to traditional synthetic polymers like polypropylene, which is ascribed to its superior electrolyte absorption and low internal resistance. (1) Exceptional Wettability & "Sponge" Effect: Unlike standard plastic separators (which are naturally water-repellent), cellulose is packed with hydroxyl (-OH) groups that make the separator act like a high-tech sponge, instantly soaking up electrolyte. This ensures that the interface between the electrode and the separator is always saturated, allowing for the fastest possible ion transport. (2) Low ESR (Equivalent Series Resistance): Cellulose separators often have a porosity of 60% to 75% or higher. The open structure of cellulose minimizes this resistance, leading to a much lower ESR compared to dense polymer films. (3) Thermal & Dimensional Stability: the melting point of cellulose remains stable up to 250°C or higher.

References: 

1. B. Huang, et al. Application for the porous structure of cellulose separators: Ionic conduction path in lithium-ion battery, J. Electroanalytical Chem., 2022, 926, 116937.
2. H. Huang, et al. Enhanced ion transport in ultrathin regenerated cellulose supercapacitor separators, J. Mater. Chem. C, 2024, 12, 9189-9199.