Metal–Organic Phase-Change Materials for Thermal Energy Storage

Abstract

The development of materials that reversibly store high densities of thermal energy is critical to the more efficient and sustainable utilization of energy. Herein, we investigate metal− organic compounds as a new class of solid−liquid phase-change materials (PCMs) for thermal energy storage. Specifically, we show that isostructural series of divalent metal amide complexes featuring extended hydrogen bond networks can undergo tunable, high-enthalpy melting transitions over a wide temperature range. Moreover, these coordination compounds provide a powerful platform to explore the specific factors that contribute to the energy density and entropy of metal−organic PCMs. Through a systematic analysis of the structural and thermochemical properties of these compounds, we investigated the influence of coordination bonds, hydrogen-bond networks, neutral organic ligands, and outer-sphere anions on their phase-change thermodynamics. In particular, we identify the importance of high densities of coordination bonds and hydrogen bonds to achieving a high PCM energy density, and we show how metal-dependent changes to the local coordination environment during melting impact the entropy and enthalpy of metal−organic PCMs. These results highlight the potential of manipulating order− disorder phase transitions in metal−organic materials for thermal energy storage.

Recent advances in phase change materials for thermal energy storage-a review

“…McGillicuddy et.al. [103], developed metal organic PCMs that can undergo tunable high-enthalpy melting transitions over a wide range of temperatures while maintaining high energy density. They used N-methylurea (MeUr) as a ligand since it has high hydrogen bond network and does not decompose.…”

Performances Assessment of Tricalcium Aluminate as an Innovative Material for Thermal Energy Storage Applications

“…With regard to the co-precipitation products, it is important to point out the discrepancy between what could be expected from the initial Ca/Al ratio and what is shown by the diffraction patterns of materials CA-32 and CA-11, in terms of phase composition. A rational explanation is given by the acid-base behavior of aluminium cations: amphoterism of Al 3+ makes its solubility increasingly relevant after pH ~9, in accordance with the tetrahydroxy aluminate ion formation [38], as described in Equation (3).…”

“…2021, 11,1958 2 of 17 the reverse (exothermic) process represents the thermal discharge, in which the products (B and C), when mixed together, regenerate the initial compound (A), releasing the previously stored energy. Thermochemical storage promises to offer numerous advantages over latent heat and sensible heat technologies, despite these technologies currently being in an advanced stage of development [2,3]. Firstly, the conversion of thermal energy into chemical energy ensures a long-term durability; in addition, the typical high-storage densities allow for significantly reduced volumes, making the storage systems easier to handle [4,5].…”

Preparation and characterization of polyethylene glycol/polyurea composites for shape stabilized phase change materials

“…[3][4][5] PCMs are a sort of smart material for storing/ releasing thermal energy in the form of latent heat from their melting/freezing process. [6,7] Based on the chemical composition, PCMs can divide into inorganic PCMs and organic PCMs. Among them, solid-liquid organic PCMs such as paraffin wax, fatty acids, fatty alcohols and their derivatives are the most widely utilized latent heat storage materials in various applications due to their extraordinary variety and high heat storage capacity.…”