A review of imidazolium ionic liquid-based phase change materials for low and medium temperatures thermal energy storage and their applications

Unexpected Energy Applications of Ionic Liquids

“…[ 24b ] The anticipated advantage of using IL PCMs in cold energy storage over traditional PCMs, is their possible intrinsic antimicrobial activity, which is urgently needed in cold chain materials. [ 25 ] Salts that feature imidazolium ions and hydrophobic alkyl chains have been identified to exhibit a broad spectrum of antibacterial properties. [ 26 ] A disadvantage of ILs in this application is their tendency to supercool, i.e., remain liquid at temperatures below T m , and in some cases produce viscous liquids that undergo a glass transition with decreasing temperature rather than crystallization.…”

“…The most studied group of ILs for thermal energy storage are imidazolium salts, covering a broad range of melting temperatures from −87 to 209 °C, depending on the imidazolium moiety functionalization (mostly with alkyl chains) and anion incorporated. [ 25 ] Nevertheless, the great majority of reported imidazolium ILs show low‐to‐moderate melting enthalpies <100 J g −1 . The outstanding examples are the geminal dicationic ILs with Δ H f reaching up to 159 J g −1 for 1,4‐bis(3‐vinylimidazolium‐1yl)butane bromide C 4 (C 2 H 4 im) 2 (Br) 2 ( T m = 125 °C).…”

“…Comparing the thermal conductivities, ILs are similar to other organic systems like paraffins or carboxylic acids and slightly lower than that of salt hydrates. [ 25 ] To enhance these properties, highly conductive graphene, graphite, carbon nanotubes, and other carbonaceous materials have been used to fabricate composite PCMs. [ 44,47,48 ] Nevertheless, such an approach increases the total cost due to the cost of these carbon materials.…”

DFT Study of the Cooperative Promotion of MgO and ZnO on CaCO3/CaO Thermochemical Heat Storage Performance of CaO

“…The utilization of renewable energy, especially solar energy, is considered to be a feasible way to solve the global warming, ecological degradation, and energy crisis. − Concentrated solar power (CSP) coupled with heat storage systems is regarded as one of the most promising technologies for the large-scale and sustainable utilization of solar energy. , Thermochemical heat storage (TCHS) technologies have been considered as the heat storage system for the next-generation CSP plants because of their wide operating temperature range, high heat storage capacities, and low heat loss. , CaCO 3 /CaO TCHS achieves the effective storage and release of solar energy through the calcium looping (CaL) (i.e., the reversible reactions of CaCO 3 calcination and CaO carbonation), as displayed in eq . With the advantages of convenient coupling with supercritical CO 2 power cycles, low feedstock prices, high heat storage density (about 3178 MJ/t theoretically), and high operating temperatures (over 800 °C), CaCO 3 /CaO TCHS is believed to be one of the most prospective TCHS technologies. , CaCO 3 ( s ) ↔ CaO ( s ) + CO 2 ( g ) 0.25em ΔH 29 8k = 178 0.25em kJ / mol …”

Ionenes as Potential Phase Change Materials with Self-Healing Behavior

“…Many anion/cation combinations have been reported by different authors, showing that ILs have a wide range of phase transfer temperatures from −96 to 359 • C, making them desirable as phase change materials (PCMs) [25,26]. Ionic liquids used as PCMs show a solid-liquid transition, which limits their potential for some applications despite improving stability and thermal conductivity compared with conventional inorganic PCMs [25,27]. However, PCMs with solid-solid transitions (SS-PCM) have been prepared from poly(ionic liquids) (PILs), which are considered polyelectrolytes and have properties of polymers and ILs [28][29][30].…”