Ultrahigh-Energy-Density Sorption Thermal Battery Enabled by Graphene Aerogel-Based Composite Sorbents for Thermal Energy Harvesting from Air

Sorption-based thermal storage has drawn considerable attention for sustainable and cost-effective thermal management and energy storage. However, the low sorption capacity of sorbents is a long-standing challenge for achieving high-energy-density sorption-based thermal storage. Herein, we demonstrate an ultrahigh-energy/power-density sorption thermal battery (STB) enabled by graphene aerogel (GA)-based composite sorbents for efficient thermal harvesting and storage with record performance. Scalable GA-based composite sorbents with high salt loading are synthesized by confined calcium chloride inside a GA matrix (CaCl2@GA), showing fast sorption kinetics and a large sorption capacity up to 2.89 g·g–1 contributed by the GA matrix and chemisorption–deliquescence–absorption of CaCl2. The STB realizes thermal charging–discharging via the multistep water desorption–sorption of CaCl2@GA sorbent with the humidity from air. Importantly, the lab-scale STB exhibits record energy density of 1580 Wh·kg–1 and power density of 815 W·kg–1 for space heating. Our work offers a promising low-carbon route for efficient thermal energy harvesting, storage, and utilization.