Compact polyelectrolyte hydrogels of gelatin and chondroitin sulfate as ion's mobile media in sustainable all-solid state electrochemical devices

Abstract

The creation of flexible and high strength hydrogel materials from natural polymers aslow cost and safe solid electrolytes is an area of intense research nowadays. We presenta novel approach for the preparation of gelatin and chondroitin sulfate hydrogelscomplexes by using a simple centrifugation process. The innovative dual-bio-gelnetworkis able to swell and shrink upon environmental changes on the pH and NaClconcentration. The solid bio-gels sandwiched between two macroporous carbonelectrodes materials are assembled in symmetric cells and their electrochemicalproperties are evaluated by cyclic voltammetry, galvanostatic, and impedancespectroscopy. The cells exhibit areal capacitance values by up to 2.74 mF/cm2 (3.1 F/g)and a low resistance value of 12 Ohm.cm2 for graphene electrode materials. Theseproperties are the consequence of the successful infiltration of the solid gel inside theporous structure of the carbon electrode that boosts the charge transfer at thebiopolymer/carbon electrode interphase. The results obtained may provide additionalinspiration in the emerging field of bioelectronics, where biocompatible and poweredsystems are of the utmost importance.