Structurally tailored nanocomposite sorbent enabling high-energy-density thermochemical storage in e-thermal banks for electric vehicle applications

Abstract

Electric vehicles (EVs) experience substantial reductions in driving range under extreme weather conditions—primarily due to the energy demands of cabin climate control (up to ∼54%) and, to a lesser extent, battery inefficiencies (∼20%). To address this issue, we propose an auxiliary energy source termed as an e-thermal bank, designed to support onboard heating, ventilation, and air conditioning (HVAC) and battery thermal management (BTM). The e-thermal bank is a high-energy-density, microwave-driven, fast-charging thermochemical storage (TCS) system that simultaneously manages cabin climate and battery temperature. To meet the stringent performance requirements of this innovative system, its key component—an advanced sorbent material—is developed through confinement of a TCS salt into a micro- and macro-structured porous matrix. The resulting optimized sorbent exhibits a high sorption capacity of 3.96 g g⁻¹, a rapid sorption rate, and a record-high material-level energy density of 10 426 kJ g⁻¹ at 90% relative humidity (RH), all the while ensuring leak-proof operation. Thanks to its structural stability and scalability, this performance translates effectively into a prototype system achieving an ultra-high energy density of 2135 Wh kg⁻¹ and power densities of 2.96 kW kg⁻¹ for heating and 3.016 kW kg⁻¹ for cooling. Theoretical evaluations based on real-world datasets indicate that incorporating the e-thermal bank could extend EV driving range by approximately 30% in winter and 20% in summer across most global regions.