Boosting solar-thermal-electric conversion of thermoelectrochemical cells by construction of a carboxymethylcellulose-interpenetrated polyacrylamide network

Abstract

Quasi-solid hydrogel-based thermoelectrochemical cells (QS-TECs) have the potential to power ubiquitous sensors needed for the internet of things (IoT). However, developing a strategy for simultaneously enhancing mechanical performance, water-retention capacity and Seebeck coefficient remains a challenge. Additionally, little attention has been paid to developing QS-TECs that are able to convert solar energy into electricity, even though solar energy is a major source of renewable energy. Here, a semi-interpenetrated QS-TEC has been designed by introducing carboxymethylcellulose (CMC) into the network of a polyacrylamide hydrogel. Because of strong interactions between CMC, the polyacrylamide network, water molecules and thermogalvanic ions, the newly designed QS-TEC showed a ∼1.5-fold better mechanical performance, ∼1.2-fold greater water retention and ∼1.05-fold higher Seebeck coefficient than a QS-TEC with a pure polyacrylamide network. Robust solar-thermal-electricity conversion was achieved by coating solar-thermal carbon nanotubes onto the surface of the QS-TEC. As a demonstration of a practical application, the solar-driven QS-TEC was successfully used as the energy supply for mechanical sensors.