Preparation and characterization of cellulose nanocomposite hydrogels as functional electrolytes

•Ecological and sustainable lithium conducting electrolytes are proposed.•Hydrogels as a three-dimensional network exhibit unique physical properties.•Incorporation of Laponite improves greatly the ionic conductivity.•The electrolytes were successfully used on NiO-based electrochromic windows.

In this work Laponite was combined with a modified abundant natural polymer, (caboxymethyl cellulose), acrylic sodium salt polymer and lithium perchlorate aiming to produce inexpensive and sustainable nanocomposite electrolytes for functional electrochemical devices. Optical, electrochemical, structural, morphological and rheological characterization was performed in order to evaluate their properties and potential advantages as electrolyte. It was verified that the addition of Laponite led to an ionic conductivity at room temperature (25 °C) in the range of 6 to 9 × 10− 5 Scm− 1 this value being then determined by the composition of the nanocomposite. These electrolytes were applied to electrochromic devices using evaporated nickel oxide thin film as the electrochromic layer. The devices exhibited a significant transmittance modulation that exceeds 45 % at 600 nm.