On the ionic conductivity and mechanical behavior of cellulose-based electrolytes: Applications for rechargeable batteries

Our paper presents two approaches that are potentially industrially scalable to prepare polymer electrolytes for the development of next-generation rechargeable batteries involving new atoms like Na, Zn or Mg: (1) gel polymer electrolytes, GPE, and (2) solid polymer electrolytes, SPE. Cellulose nanocrystals (CNC) are used with different surface functions, surface charge and concentrations as a functional component in both systems. Systematic testing of their ionic conductivity as well as their dynamic mechanical behavior, which is critical for creating mechanically durable systems, has been performed. Higher ionic conductivity reaching up to 2.60 +/- 0.57 mS/cm was obtained for cellulose based GPE, which is more than double the ionic conductivity tested for non-renewable Celgard (R) 2400 (1.15 +/- 0.06 mS/cm). Whereas cellulose based SPE showed an ionic conductivity of up to 2.34 +/- 0.28 x 10-6 S/cm, and in both systems, tailoring the surface charge on CNC surfaces significantly influenced the counterion mobility thereby improving the ionic conductivity.