An official website of the United States government
Redox‐Active Oxide/molten Salt Composites for Hybrid Thermal‐Chemical Energy Storage
Structurally stabilized composites are promising for using phase change materials in high‐temperature thermal energy storage (TES). However, conventional skeleton materials, which typically comprise 30–50 wt% of the composite, mainly provide sensible heat storage and contribute minimally to overall energy density. This study introduces a new class of redox‐active oxide‐molten salt (ROMS) composites that overcome this limitation by combining sensible, latent, and thermochemical heat storage in a single particle. Specifically, porous, redox‐active Ca2AlMnO5+δ(CAM) complex oxide particles were demonstrated as a suitable support matrix, with the pores filled by eutectic NaCl/CaCl2salt. X‐ray diffraction confirms excellent phase compatibility between CAM and the salt. Scanning electron microscopy/energy dispersive X‐ray spectroscopy and nano X‐ray tomography show good salt infiltration and wettability within the CAM pores. Thermogravimetric analysis reveals that a 60 wt% CAM/40 wt% salt composite achieves an energy density of 267 kJ kg−1over a narrow 150 °C window, with ≈50 kJ kg−1from thermochemical storage. Additionally, the composite shows higher thermal conductivity than salt alone, enabling faster energy storage and release. ROMS composites thus represent a novel and efficient solution for high‐performance TES.
more »
« less
- PAR ID:
- 10637665
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Advanced Energy and Sustainability Research
- ISSN:
- 2699-9412
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
Cellular solids composed of a network of interconnected pores offer low‐density and high strength‐to‐weight ratio as exemplified by wood, bones, corks, and shells. However, the slender edges and low connectivity of the structs in cellular lattices make them vulnerable to buckle, fracture, or collapse. Here, by taking advantage of the continuity of a thin film that can follow curvatures and dissipate energy, shellular materials are created by dip coating a wireframe of the primitive triply periodic minimal surface (TPMS) with an aqueous solution of lyotropic liquid crystalline graphene oxide (GO)/polymer composites. Regulated by surface tension, GO nanosheets align on the polymer soap film as the stress builds up during drying. When the wireframe mesh density is low, the shellular material is film‐dominated, demonstrating superior mechanical strength (384.30 Nm kg−1) and high specific energy absorption (1.59 kJ kg−1) yet lightweight (equivalent density, 0.063 g cm−3), with an energy absorption rate comparable to that of carbon nanotube‐based lattices but a lower equivalent density. The study offers insights into designing lightweight yet high‐strength structural materials that also function as impact energy absorbers.more » « less
-
Thermochemical energy storage is promising for building applications as it offers high energy density and near-lossless storage. For example, inorganic salt hydrates that undergo reversible solid-gas thermochemical reactions can be used for thermal load shifting and/or shedding in buildings. However, this technology is still in early stages of development and drawbacks need to be addressed to make such a thermal battery viable. As salt hydrates differ in their morphology, crystal and/or particle size, and hygrothermal stability, it is critical to characterize thermochemical reactions accurately under specific operating conditions. Not only is the amount of heat delivered important, but so is the rate at which this heat is extracted for thermal end-use in buildings. However, the latter is not well reported in the literature, which is largely focused on energy storage rather than power density during the hydration reaction (battery discharge). To address this gap and the lack of standardized measurement methods, this work lays out a systematic simultaneous thermal analysis (STA) method for characterizing five different salt hydrate thermochemical materials (TCM). The effects of particle size, temperature and vapor pressure are analyzed to obtain the energy storage density and thermal power density across a full hydration-dehydration cycle under controlled conditions.more » « less
-
Abstract. As the global demand for sustainable energy intensifies, Concentrated Solar Power (CSP) systems offer a promising solution by converting solar thermal energy into electricity. However, the intermittent availability of sunlight necessitates efficient thermal energy storage to ensure uninterrupted power generation. Thermochemical energy storage (TCES) systems, particularly those utilizing metal oxides (MOs), present a high-density and long-duration energy storage alternative. Although experimental investigations associated with the application of La-based perovskites are available in the published literature, studies focussing on thermodynamics equlibrium and efficiency analysis are limited. Hence, in this study, the thermochemical performance of La0.5Sr0.5CoO3 (LSC55), a perovskite oxide, is analyzed to evaluate its potential for high-temperature TCES applications. A detailed non-stoichiometric and van’t Hoff analysis was performed to assess the redox behavior and quantify the energy storage capacity of LSC55 across a range of oxygen partial pressures (P_(O_2 )) and reduction temperatures (T_red). Results indicate that O2 release and corresponding non-stoichiometry (δ) increase with T_red and decrease in P_(O_2 ), achieving a maximum δ of 0.598 at 1473 K and 0.0001 atm. The van’t Hoff analysis further revealed that the TCES capacity of LSC55 varies significantly with δ, reaching up to 236.5 kJ/kg at optimal conditions. These findings establish LSC55 as a viable and tunable material for advanced TCES in CSP systems, supporting efforts toward a more stable and renewable energy future.more » « less
-
ABSTRACT The use of iron metal powder directly as the cathode active mass is a transformative opportunity to increase energy density and reduce costs for rechargeable batteries. Realizing this potential, however, requires creating a chemical environment that can activate multiple‐electron transfer of iron redox chemistry. Here, we report that the composite synthesized by ball milling Na2SO4, Fe metal, and CuS can be directly desodiated as a sodium‐ion battery cathode, which delivers a reversible discharge capacity of 149 mAh g−1at ~2.6 V with stable cycling performance. Comprehensive spectroscopic characterization reveals that Fe serves as the primary redox center, while CuS functions as a redox mediator. The results demonstrate that the heterointerfaces formed by ball milling are critical for charge transfer and high iron utilization. This work establishes iron metal sodium‐salt composites as viable sodium‐ion battery cathodes by unlocking multi‐electron Fe redox within a composite architecture.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/aesr.202500196
