Solar and Thermal Multi-Sensing Microfiber Supercapacitor with Intelligent Self-Conditioned Capacitance and Body Temperature Monitoring
A solar and thermal multi-sensing all-solid-state microfiber supercapacitor (ASSMFSC) with prominent electrochemical and mechanical performance, reliable environmental responsivity, and intelligent self-conditioned capacitance are constructed by using cellulose nanofibrils-graphene-conjugated polymer, which assemblies as both a core-sheath microfiber electrode (CSMFE) and a sensing unit. Multicomponent hierarchical synergistic design fully exploits of the unique attributes and synergy interaction of each component to endow well-designed CSMFE with highly capacitive and mechanically robust, as well as excellent thermal sensitivity and photothermal conversion function, enabling valid modulation of redox reactions, interface performance, or electronic/ionic transfer in microfiber supercapacitors toward complex external stimulations and building interrelated working responses. The fabricated ASSMFSC presents a total volumetric (vs the whole device) capacitance of 85.8 mF cm-3, excellent cycle stability, and volumetric energy density of 11.9 mWh cm−3. Moreover, ASSMFSC shows delightful solar-thermal conversion capacitance enhancement, at one solar power density (1 kW m-2), the capacitance is two times compare with that of the device in the dark and performs self-regulation capacitance ability with the change of solar intensity. As a thermosensitive device, ASSMFSC with a current sensitivity of 0.47437 ± 0.00549 °C-1 displays a fast response and excellent reproducibility to sense subtle temperature changes. This work demonstrates that CSMFE-driven microfiber supercapacitor can use in photothermal conversion energy storage system and body temperature monitoring, which provides an essential reference and optimistic incentives for new generation energy-related devices.