Chemical Modification and Processing of Chitin for Sustainable Production of Biobased Electrolytes

Abstract

In the present work we report on the development of a novel and sustainable electrolyte based on chitin. Chitin biopolymer was carboxymethylated in simple, mild, and green conditions in order to fine-tune the final properties of the electrolyte. To this end, chitin was modified for various reaction times, while the molar ratio of the reagents, e.g., sodium hydroxide and monochloroacetic acid, was maintained fixed. The resulting chitin derivatives were characterized using various techniques. Under optimized conditions, modified chitin derivatives exhibiting a distinct degree of carboxymethylation and acetylation were obtained. Structural features, morphology, and properties are discussed in relation to the chemical structure of the chitin derivatives. For electrolyte applications, the ionic conductivity increased by three magnitudes from 10−9 S·cm−1 for unmodified chitin to 10−6 S·cm−1 for modified chitin with the highest degree of acetylation. Interestingly, the chitin derivatives formed free-standing films with and without the addition of up to 60% of ionic liquid, the ionic conductivity of the obtained solid electrolyte system reaching the value of 10−3 S·cm−1.

Addressing the Needs of the Rapidly Aging Society through the Development of Multifunctional Bioactive Coatings for Orthopedic Applications

“…CMCh is pH-sensitive, has moisture-retention abilities, and has an emulsion stabilizing capacity [ 107 ]. Homogenous modification of natural chitin to produce CMCh is challenging due to the crystalline structure of chitin and the high degree of acetylation [ 108 ].…”

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“…Chemical modification is a familiar method that modifies polysaccharide structure by introducing substituent groups in the structures. This modification helps to reinforce the polysaccharide bioactivities, including antioxidant, antithrombotic and antitumor activity 8 . It deals with selective derivatization and degradation of polysaccharides for structure elucidation.…”

Ionic liquid-assisted synthesis of chitin–ethylene glycol hydrogels as electrolyte membranes for sustainable electrochemical capacitors

“…Chitin is isolated in the form of flakes or powder, and due to its chemical resistance, it requires various treatments to process it into a form tailored to a specific application. On the other hand, the high chemical stability of chitin is the main advantage of the use of this biopolymer as a polymer matrix for the hydrogel electrolyte in electrochemical capacitors, ensuring proper resistance in various liquid electrolytes 23 , 24 . Technological development has equipped scientists with new tools and methods for processing this polymer into desired forms 25 – 31 .…”