Constructing robust and recyclable self-powered polysaccharide-based hydrogels by adjusting Zn2+/Li+ bimetallic networks†

The fundamental requirements of self-powered hydrogels used in flexible electronic products encompass excellent mechanical performance and conductivity. However, simultaneously achieving high performance in both the aspects remains a great challenge during the fabrication of self-powered hydrogels. In this study, robust and recyclable self-powered polysaccharide-reinforced polyvinyl alcohol (PVA) networks were established by modulating ionic channels using Zn²⁺/Li⁺ bimetallic salt solutions. The results indicate that the hydrogel equilibrated in a bimetallic salt solution of 1 M concentration can simultaneously achieve an impressive tensile strength of 1.36 MPa and an optimal ionic conductivity of 1.64 S m⁻¹ since carboxyl groups on the polysaccharide chains enable the adsorption of more metal ions without restricting ionic mobility as a result of higher conductivity. By leveraging their excellent electrochemical performance, conductive hydrogels can serve not only as flexible sensing materials with enhanced sensitivity to monitor human motion and facilitate information transmission, but also as recyclable electrolytes in self-powered hydrogel batteries. Interestingly, self-powered hydrogel batteries can maintain a stable voltage of 0.82 V and show good recyclability, which can restore the original voltage output via a simple salt solution equilibration method, offering significant potential in applications such as wilderness survival. This work provides a novel strategy for the rapid and green preparation of robust, recyclable, and self-powered polysaccharide-based hydrogels.