Highly transparent sustainable biogel electrolyte based on cellulose acetate for application in electrochemical devices.

In this study, an easy and low-cost production method for a cellulose acetate-based gel polymer containing lithium perchlorate and propylene carbonate is described, as well as the investigation of its properties for potential use as an electrolyte in electrochemical devices. Cellulose acetate, a biopolymer derived from natural matrix, is colourless and transparent, as confirmed by the UV-Vis spectroscopy, with 85 % transparency in visible spectrum. The gels were prepared and tested at different concentrations and proportions to optimise their properties. Thermogravimetry, XRD, and FTIR analyses revealed crucial characteristics, including a substantial 90 % mass loss between 150 and 250 °C, a semi-crystalline nature with complete salt dissociation within the polymer matrix, and a decrease in intensity at 1780 cm ^-1 with increasing Li ⁺ ion concentration, suggesting an improvement in ionic conduction capacity. In terms of electrochemical performance, the gel containing 10 % by mass of cellulose acetate and 1.4 M of LiClO ₄ emerged as the most promising. It exhibited a conductivity of 2.3 × 10 ^-4 S.cm ^-1 at 25 °C and 3.0 × 10 ^-4  S.cm ^-1 at 80 °C. Additionally, it demonstrated an ideal shape of cyclic voltammetry curves and stability after 400 cycles, establishing its suitability as an electrolyte in electrochemical devices.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper.
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