Multifunctional energy harvesting and storage textile technology based on thermionic effect
Rui S. Costa, Ana L. Pires, André M. Pereira, Clara Pereira
Abstract
The development of effective dual-function energy harvesting/storage technologies is a milestone demand for the emerging generation of low-consumption autonomous electronics. This work reports the development of a multifunctional thermionic power textile device merging thermal energy harvesting and electrochemical energy storage for application in self-powered systems. An everyday cost-effective non-conductive natural fabric was transformed into an all-solid-state textile-based thermally-chargeable supercapacitor (T-TCSC) via dyeing with multiwalled carbon nanotubes and subsequent assembly with H3PO4-doped poly(vinyl alcohol) (PVA) solid-gel polyelectrolyte. When subjected to an out-of-plane temperature gradient, the T-TCSC was able to convert the thermal energy into electrical output and store the harvested energy. A Soret coefficient of 1.85 mV K−1 was obtained, which is the highest value achieved so far for TCSCs developed on non-conductive textile substrates reported in literature and ∼10× higher than those of conventional thermoelectric devices. Additionally, a maximum output potential of ∼30 mV was achieved for ΔT = 24.7 K. Concerning the energy storage performance, an energy density of 9.39 μW h cm−2 was obtained at 1.62 mW cm−2 power density. The smart T-TCSC outputs demonstrated its potentialities as a two-in-one self-chargeable textile device that can harvest the thermal energy generated by a temperature gradient, convert it into electrical energy and simultaneously store it.