CO2-crosslinked Cellulose for Radiative-cooling-driven Passive Thermoelectric Devices: One Stone Two Birds

Abstract

Radiative-cooling-driven passive thermoelectric device (RC-TED) offers a potentially sustainable energy solution. However, most RC-TED strategies utilize unsustainable polymers. Herein, a green and sustainable CO2-crosslinked cellulose (Pulp-CO2) was developed for use as both a passive radiative cooling membrane and an ionogel thermoelectric scaffold. The incorporation of CO2 in the form of carbonate group linkages in the cellulose backbone endows it with superior passive radiative cooling effect of the membrane and thermoelectric efficiency of the ionogel to the pure Pulp. The integrated RC-TED, comprising of the Pulp-CO2 membranes and ionogels, could output an impressive thermal voltage of 1200 mV with a subambient temperature reduction of 5.0 °C under simulated solar radiation (280 W·m-2), highlighting its potential in low-grade energy harvesting. This all-cellulose inspired RC-TED device showcases a promising and sustainable strategy for converting solar energy cost-effectively into electricity.