Molecular tailoring to improve polypyrrole hydrogels’ stiffness and electrochemical energy storage capacity

This research looks at ways of tailoring and improving the stiffness of polypyrrole hydrogels for use as flexible supercapacitor electrodes. Molecules providing additional cross-linking between polypyrrole chains are added post-polymerisation but before gelation, and are found to increase gel stiffness by up to 600%, with the degree of change dependent on reactant type and proportion. It was also found that addition of phytic acid led to an increase in pseudocapacitive behaviour of the hydrogel, and thus a maximum specific capacitance of 217.07 F·g−1 could be achieved. This is an increase of 140% compared to pristine polypyrrole hydrogels produced by this method.