Concentrated Solar Power Generation Research Articles

Economic Impact of CSP Plants with Storage Addressing the Energy Transition in Locations with High Electricity Demand in Chile

This study explores the economic implications of hybrid plants combining photovoltaic (PV) and Concentrated Solar Power (CSP) technologies with energy storage in response to Chile's ongoing energy transition. Utilizing the System Advisor Model (SAM), six diverse locations were evaluated to assess energy generation profiles, calculate the Levelized Cost of Energy (LCOE), and analyze gross margins. The key finding is that higher solar multiples or storage capacities do not consistently lead to lower LCOE, primarily due to operational strategies aligning CSP generation profiles with PV. Notably, northern regions consistently yield higher gross margins despite occasional zero marginal costs, while areas near Santiago experience lower gross margins, with Salamanca presenting the lowest margin. This highlights the critical role of available solar resources in shaping economic outcomes.

Corrosion of 316 SS in chloride molten salt for thermal energy storage: Inhibitory effects of Al powder

Abstract MgCl2-KCl-NaCl is regarded as one of the most prospective high-temperature thermal energy storage mediums and heat transfer fluids (HTF) for 3rd generation concentrated solar power (CSP) systems. However, high corrosion to alloys limits its application. In this paper, corrosion tests were conducted on 316 SS, in MgCl2-KCl-NaCl at 800°C with different content (0 wt.%,1 wt.%, and 10 wt.%) of Al powder addition as a corrosion inhibitor. The impact of Al powder was assessed through electrochemical methods, specifically impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). Following corrosion tests, the morphologies and phase compositions of 316 SS were determined by using scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) and X-ray diffraction (XRD). The addition of Al powder can significantly reduce the corrosion current density of 316 SS in MgCl2-KCl-NaCl at 800°C, which was 183.29 times higher than that with 10 wt.% without Al addition. Al and the degree increased with increasing content of Al. With the addition of 1 wt.% Al, the thickness of the diffusion layer is significantly reduced, which was 54.6 μm (100 h), 275.1 μm (200 h), 370.4 μm (300 h), and 500 μm (400 h), respectively. When the addition of Al reaches up to 10 wt.%, the inwards diffusion of Al caused the formation of Al enriched layer, which was identified as the FeAl phase, on the surface of 316 SS during the high-temperature corrosion processes. The thickness of the Al enriched layer was associated with the diffusion time of Al, and its depth was 40.4 μm (100 h), 45.3 μm (200 h), 103.5 μm (300 h), and 139.5 μm (400 h).

Development of Readily Available & Robust High Heat Flux Gardon Gauges

Concentrated solar power (CSP) technologies deliver concentrated solar energy as a heat source to industrial processes, power generation cycles, and chemical cycles. CSP systems require accurate and reliable high flux measurements, and next generation CSP systems will require flux measurement up to 1000 W/cm2. Existing flux measurement devices do not comprehensively meet the flux rating, cycle life, cost, and lead-time needs of stakeholders, necessitating the development of an improved flux sensor. In this study, Sandia National Laboratories (SNL) partnered with Hukseflux Thermal Sensors to develop a low-cost, short lead-time, and robust flux sensor rated to 250 W/cm2. Three prototype circular foil gauge designs were assessed for performance at the National Solar Thermal Test Facility (NSTTF) at SNL. Each gauge design measured flux up to 250 W/cm2 with <5% measurement error. Following baseline error quantification, gauges were exposed to flux above 500 W/cm2 to assess gauge failure mechanisms. Gauges physically survived >500 W/cm2 flux exposure, but measurement error was found to increase after foil coatings reached 400 °C. The results of this study suggest that coating optical properties change at excessive temperatures and that foil coating temperature, rather than heat flux level, dictates the acceptable gauge measurement range.

Corrosion evaluation of austenitic stainless steels in Li2CO3-K2CO3 eutectic salt for thermal energy storage

Molten carbonate salt is one of the promising candidates for high-temperature thermal energy storage tailored towards advanced pumped-thermal energy storage and next generation concentrated solar power technologies. However, severe corrosion of structural materials exposed to molten carbonate salts poses one of the most pivotal threats in terms of limiting their large-scale application at ever-escalating temperatures. Here, we elaborate the compatibility of three commercial austenitic stainless steels specifically SS310, SS316L and Incoloy 625 with Li2CO3-K2CO3 (28–72 wt%) eutectic salt. The corrosion behavior and corrosion mechanism of Fe-Cr (SS316L), Fe-Cr-Ni (SS310) and nickel-based (In625) alloys at 600 °C in air were also investigated. It revealed that SS310 exhibited better corrosion resistance compared to SS316 and In625, with weight loss of 23.8 mg/cm2 and corrosion rate of 522 μm/year after 500 h of exposure at 600 °C. This implies that higher Ni content of the alloy may not necessarily improve the corrosion resistance, it is associated with the basicity of the molten and the solubility of Ni salt in the melt. ICP analysis indicated that the salts exposed to SS310 and In625 at the same exposure time both had nearly 11 times more Ni than that exposed to SS316. Precisely, it is related to the behavior of the Cr-enriched zones formed in the corrosion layers of different alloys. The corrosion mechanism of SS310 specimens in molten carbonate can be generally divided into the following steps: (i) selective oxidation of the metal elements and lithiation reactions of the metal oxides to generate a passivation scale, (ii) an ever-growing middle transition scale consisted of mixed metal oxides and lithium-containing compounds, (iii) cracking and peeling off of the corrosion scale.

Study on CaO-based materials derived from steel slag for solar-driven thermochemical energy storage

The calcium looping (CaL) technique, renowned for its exceptional ability to withstand high temperatures and remarkable heat storage capacity, perfectly complements 3rd generation concentrated solar power (CSP) plants. However, the poor cycling stability and low spectrum absorption rate of CaO obstruct system efficiency. In order to tackle these problems, we impregnated steel slag with acetic acid and doped Mn to create a novel CaO-based energy storage material. Thermogravimetric analysis (TGA) and fixed-bed cycling of the material revealed that the material has outstanding cyclic heat storage properties. Compared to CaO, the material has an 85 % higher initial adsorption rate, 73 % higher 30-cycle energy storage density, and 9.5 times higher average light absorption. Spherical pellets were prepared for industrial applications through the extrusion-spheronization method. The energy storage density for 30 cycles was reduced by 10.26 % for the pellets compared to the powder material, but the average light absorption rate was improved. The compressive strength of the composite pellets was 8.4 times higher than the dolomite pellets. It was found that the light absorption capacity of the material increased with the number of cycles, which was attributed to the migration of Mn and Mg from the interior to the surface. Finally, the excellent photothermal conversion capability of the new composite material was verified by the photothermal conversion test. Therefore, Mn-doped CaO-based composite material derived from steel slag is promising for application in the next-generation CaL-CSP system.

Thermal performance of MgCl2–NaCl–KCl eutectic salt for the next generation concentrated solar power and correlation between structure and thermophysical properties: Insights from atomic and electronic levels

MgCl2–NaCl–KCl (MgNaK) eutectic salt has emerged as a highly promising candidate for concentrated solar power (CSP), with extensive research conducted in recent years. However, the thermal property data for the MgNaK eutectic salt are still very limited. Here, we present a novel and accurate many-body potential trained by machine learning (ML) for MgNaK eutectic salt (with mole fractions of 45.4 %, 33 %, and 21.6 % respectively), developed using energies and forces extracted from first-principles molecular dynamics calculations (FPMD). The performance of the potential is well tested. We conduct a detailed investigation on the temperature-dependent structural and corresponding thermal properties, analyzing them from both the atomic and electronic perspectives. The introduction of Na+ or K+ ions disrupts the net structure formed by corner-joint and edge-joint MgClx units, thereby affecting the transport properties. The calculated density (ρ) and constant pressure specific heat capacity (CP) exhibit agreement with experimental data within a margin of 2 %. We observe and discuss the typical λ of negative linear temperature correlation, which is similar to other molten alkali chloride salts. Finally, based on the simulated and experimental values, we provide reliable recommendations for the λ and viscosities (η) of MgNaK eutectic salt across its entire operating temperature range.

Dynamic Corrosion of Carbonate Salt for 3rd Generation CSP Plants

Eutectic ternary carbonate salt is one of the candidates for 3rd generation concentrated solar power (CSP) plants. Gen3 CSP targets higher operation temperatures, which strengthens the corrosivity issues associated to molten salts. Although there are corrosion studies for this carbonate salt in static conditions, the effect of salt flow is not fully understood. In this work, corrosion experiments under static and dynamic conditions are compared for SS310 subjected to ternary carbonate salt at 600ºC.
 The corrosion layer formed during static and dynamic tests were completely characterized by means of SEM-EDX and XRD (surface and cross-section). The corrosion products deposited in the salt during the experiment were analyzed by ICP-OES.
 The tests performed under dynamic conditions demonstrated an increase spallation of the corrosion layer. This spallation produced a thinner scale and exposed the Cr containing phase to the molten salt, fostering its dissolution. These results confirmed the significant effect of dynamic conditions on the corrosivity of eutectic ternary carbonate salt and the importance of assessing them in the design of 3rd generation CSP plants.

Incorporation of CaZrO3 into calcium-based heat carriers for efficient solar thermochemical energy storage

Calcium-based materials (CaCO3/CaO) have shown significant potential for use in thermochemical energy storage systems for concentrated solar power generation due to their low-cost, high-energy storage efficiency, and operational temperature range. However, the energy storage performance of calcium-based heat carriers degrades rapidly over cycles due to high-temperature sintering, limiting practical applications. In this study, we incorporated Zr into CaO using both heat-drying and freeze-drying methods, forming CaZrO3 as a physical barrier to prevent agglomeration and sintering of calcium particles at elevated temperatures. Experimental results demonstrated that Zr incorporation markedly improved cyclic energy storage stability, particularly for heat carriers derived from freeze-drying. Cao incorporated with 10 % CaZrO3 (FD-Zr10) showed a high energy storage density of 2161.75 kJ/kg over ten storage/release cycles, which was 25.89 % higher than that of pure CaO sample. Even over an extended operation of 30 cycles, FD-Zr10 still possessed the high energy storage density of 1939.76 kJ/kg. CO2-containing harsh storage conditions caused more sintering for the heat carriers, thus resulting in the performance reduction, but FD-Zr10 performed much better than other samples in resisting sintering. Various characterization analyses were conducted to investigate the reasons for the samples' cyclic stability. It was discovered that freeze-drying incorporation generated a dendritic surface with a more abundant pore structure, and the incorporated CaZrO3 functioned as a metal skeleton to mitigate high-temperature sintering.

High performance Mn/Mg co-modified calcium-based material via EDTA chelating agent for effective solar energy storage

Calcium-based material is a very promising candidate energy storage material for next generation concentrated solar power (CSP) plants with operation temperatures above 700 °C. However, performance decay and poor solar absorption capacity limit the large utilization of calcium-based material. Here, ethylene diamine tetraacetic acid (EDTA)-assisted sol–gel method is first employed to modify CaO with magnesium (Mg) and manganese (Mn) elements. MgO and Ca2MnO4 nanoparticles are attached to the surface of CaO particles to separate grains spatially to inhibit sintering. In addition to the external separation effect, Mn elements are found to be doped successfully into CaO crystal lattice rather than simply mixed, which restrains atomic diffusion and agglomeration inside CaO and thus further inhibits sintering more efficiently. The Mg and Mn co-doped sample (Ca:Mn:Mg = 9:1:2) synthesized by EDTA demonstrates exceptional thermal stability at 800 °C. The performance decay is only 6.3 % after 100 cycles and mainly manifests in the first ten cycles (4 %). Furthermore, by combining two-step calcination to avoid agglomeration and uneven doping, we also obtain the co-doped sample (Ca:Mn:Mg = 9:1:1) with nearly no performance decay in 100 cycles. The proposed materials possess an average solar absorptance of 67 %, about 4 times that of pure calcium material. This work not only designs energy storage materials with excellent performance expected to be applied in the next generation CSP plant but also provides a lattice doping route for calcium-based material modification.

Improving the Heat Transfer Performance of the Tower Molten Salt Solar Receiver With the Novel Folded Flow Tubes

Abstract The molten salt has been widely used in concentrated solar power generation as an effective high-temperature heat transfer and heat storage working fluid. However, due to the concentrating characteristic of the tower receiver, the solar flux distribution of the molten salt receiver is extremely non-uniform, and thus the circumferential non-uniform heat flux has a prominent effect on the heat transfer performance and reliability of the traditional solar molten salt receiver tube (TRT). In this contribution, in order to solve above problems, we propose some novel folded flow tubes (NFTs), which add a partition in the tube and seal the top with end cap so that the inflow and outflow of the fluid can only proceed from the same cross section. Then, we apply the binary nitrate (solar salt) as a heat transfer fluid, which is a mixture of 60% sodium nitrate and 40% potassium nitrate. First, we analyze some effects such as flow parameters, structure, and heat flux loading direction on the convective heat transfer performance of the NFTs. The results show that the circumferential temperature difference of NFTs is about 17–92 K lower than that of TRT, and the molten salt temperature distribution is more uniform accordingly. Moreover, the heat transfer coefficient is increased about 88.37–122.85%, which can provide a guidance for the structural optimization of practical solar molten salt receivers to improve the heat transfer performance and reliability.

Techno-economic assessment of concentrated solar power generation in Saudi Arabia

Saudi Arabia plans to shift a large portion of its domestic energy production away from fossil fuel towards solar energy by 2030. Yet, the solar energy pool is mainly targeting photovoltaic technology. This study analyzes the potential of cleaner energy production from solar energy using concentrated solar power technology. First, different locations for concentrated solar power technology deployment are assessed based on potential development opportunities, solar resources, and infrastructure. Second, the paper assesses the performance and financial feasibility of four concentrated solar power technologies using the capacity factor, levelized cost of energy, and energy yield. The analysis indicates that all the considered locations are suitable for concentrated solar power technologies with a preference for the NEOM city located in the northern region of Saudi Arabia. The simulation results revealed that solar tower technology produces the highest energy yield of 2738 kWh/kW. The levelized cost of energy for the four technologies varies between 14.54 – 22.67 ¢/kWh, with linear Fresnel demonstrating the lowest and parabolic trough exhibiting the highest levelized cost of energy.

Synthesis of dark Li4−3xFexSiO4 for simultaneous direct solar thermal conversion and durable thermochemical energy storage

Thermochemical energy storage (TCES) technique based on Li4SiO4 looping system probably offers a mid-term if not near-term solution to the next generation concentrated solar power (CSP) plants featured with excellent stability and low regeneration temperature. However, traditional Li4SiO4 material commonly possesses dense microstructure with white superficial color, thus resulting in the unsatisfactory energy storage density and considerable radiant heat loss. This study involved doping Fe into Li4SiO4 to synthesize dark Li4−3xFexSiO4 heat carriers for thermochemical energy storage (TCES). By replacing Li+ with Fe3+, vacancies were created in the crystal lattice structure, resulting in the high energy storage density (456.14 kJ/kg) as well as the excellent cyclic long-term stability of I-Li3.7Fe0.1SiO4. Furthermore, Fe-doped dark Li4SiO4 showed obviously enhanced direct solar absorptance with the average solar absorptance of I-Li3.7Fe0.1SiO4 being 10 times higher than that of the undoped Li4SiO4. Such obvious enhancement in solar absorptance was attributed to the darkening superficial color through Fe doping. In summary, the synthesized Fe-doped Li4SiO4 heat carrier solved the encountered problems of traditional energy storage materials and exhibited as a promising heat carrier for practical thermochemical energy storage.

Hydrodynamics of a Multisized Particle Mixture in Shallow Fluidized Bed With Immersed Tubes

Abstract Inert solid particles have made the integration of more efficient power cycles with super high operating temperatures into the concentrated solar power (CSP) station feasible. Fluidized bed heat exchangers with feature of high heat transfer coefficient have great application potential in the particle-based CSP. However, the parasitic loads of the additional fluidizing gas loop and the finely sieved monosized particles may deteriorate the economic efficiency of the integrated system. In order to cope with this problem, a conceptual design of a shallow fluidized bed (SFB) heat exchanger is proposed for the new generation CSP technology. Fluidization characteristics of bauxite particles with a nonuniform particle size distribution in SFB with immersed tubes are investigated with a combination of experimental measurements and computational fluid dynamics simulations. Results show that the static bed height and opening area ratio of the distributor has insignificant influence on the range of semifluidized region and the minimum fluidization velocity Umf. The standard deviation of bed pressure drop σ in the grid region can be used as an alternative criterion for identifying the fluidization state. A range of superficial velocity that distinguishes two different solid circulation patterns exists, with its boundary values being four times and eight times the Umf, respectively. The immersed tubes can inhibit the asymmetric particle circulation patterns from developing in the SFB, but cause a substantial increase in the σ within the grid region.

Enhancing solar absorption and reversibility in calcium looping-based energy storage via salt-promoted CaO

Calcium looping (CaL)-based solar to thermochemical energy storage is a promising option for long-term thermal energy storage in concentrated solar power generation. CaL is a chemical looping process involving reversible carbonation-calcination reactions among CaO, CO2, and CaCO3, which has distinct advantages, such as high energy storage density at high operating temperatures. However, the low optical absorption of CaO limits its application as a direct solar absorbing material, and the continuous reduction of reactivity through CaL reactions degrades the energy storage ability. In this work, we investigated the multi-doping of transition metals Fe, Co, Ni, and CaCl2 to improve optical absorption and promote the carbonation reactivity of synthetic CaO-based materials. The synthetic CaO materials were synthesized by acetic acid-based wet mixing and sol–gel method. Proposed materials exhibited significantly enhanced optical absorption up to 88%, preserved within 78 – 85% throughout 45 cycles of CaL reactions. The production and regeneration of Ca2FeO3Cl are expected to enhance optical absorption. The CaL reaction analysis revealed better carbonation conversion performance holding with cyclic stability, achieving 1.94 MJ/kg for 50 cycles or 1.17 MJ/kg for 100 cycles. The reaction mechanism was investigated using in-situ high-temperature XRD, and a salt-promoted carbonation mechanism is proposed, which consists of Ca2FeO3Cl carbonation and carbonation in a molten salt phase, improving the mass transfer of Ca2+O2– to adsorbed CO2. Based on the findings, we suggest the synergistic use of the CaCl2 multi-doping method for synthetic CaO designs.

Experimental Investigation of Soapstone and Granite Rocks as Energy-Storage Materials for Concentrated Solar Power Generation and Solar Drying Technology.

The intermittence of solar energy resource in concentrated solar power (CSP) generation and solar drying applications can be mitigated by employing thermal energy storage materials. Natural rocks are well recommended thermal energy storage materials as they are efficient for CSP generation. This study explores the potential of soapstone rock and also the influence of the sites' geo-tectonic setting to soapstone and granite rocks as thermal energy storage materials. Experimental characterization was done to investigate the thermo-chemical properties (thermal stability (TGA), crystalline phases (XRD), petrographic imaging and chemical composition (XRF), and high temperature test); the thermo-physical properties (density, porosity, specific and thermal capacity (DSC), thermal diffusivity, and conductivities (LFA)); and the thermo-mechanical properties (Young's modulus) of the rocks. Consequently, the rock with the most desired properties for thermal energy storage was the soapstone rock from the Craton geo-tectonic setting and it had a Young's modulus of 135 GPa at room temperature. At solar drying and CSP temperatures it had thermal capacities of 3.28 MJ/(m3·K) and 4.65 MJ/(m3·K); densities of 2.785 g/cm3 and 2.77 g/cm3; and conductivities of 2.56 W/(m·K) and 2.43 W/(m·K) respectively, and had weight loss of 0.75% at 900 °C. At high temperatures, only granite from Craton had visible cracks while the other 3 rocks did not show visible signs of fracture. Conclusively, soapstone and granite from Craton in the Dodoma region and Usagaran in the Iringa geo-tectonic settings exhibit significant differences in most thermo-properties.

Early-stage corrosion of IN 740H alloy in eutectic NaCl-KCl molten salt at high temperatures

The next generation concentrated solar power plants are expected to operate at temperatures above 700 °C and this would necessitate heat storage media such as chloride salt mixtures to be used for better heat transfer and energy storage. In this perspective, the corrosion behaviour of a commercial grade IN 740H alloy is being investigated in the eutectic equimolar NaCl-KCl salt mixture, at 700 °C and 800 °C. To evaluate and understand the early stages of corrosion of IN 740H, electrochemical and gravimetric tests were carried out after exposure to molten eutectic NaCl-KCl salt mixture for 1.5 and 24 h, respectively. The quantitative outcomes of the gravimetric studies suggest that IN 740H corrodes at 0.29 ± 0.03 and 0.59 ± 0.17 mg cm−2 day−1 at 700 °C and 800 °C, respectively. Tafel measurements reveal corrosion rates similar to those measured by gravimetric method. Electrochemical impedance spectroscopy analysis indicated the diffusion-controlled corrosion behaviour, but the passive layer does not inhibit corrosion at early stages. A correlation between the underlying mechanism and the oxide scale microstructure has been presented using electrochemical and cross-sectional studies.

Prediction of thermal transport properties for Na2CO3/Graphene based phase change material with sandwich structure for thermal energy storage

In this paper, a new Na2CO3/Graphene based phase change material (PCM) with sandwich structure was proposed and designed for the application of thermal energy storage, the microstructure of which was established, and its thermal transport properties were investigated by means of molecular dynamics simulations, and the prediction method for transport properties with desired accuracy was also developed and determined. The results indicate that the construction of sandwich structure leads to the limiting effect of ions contained in the PCM simulation system, and the self-diffusion coefficient was reduced and shear viscosity was increased. Besides, the construction of sandwich structure was benefit to the thermal conductivity enhancement, the thermal conductivity of PCM can be increased by 32.51% on average in the studied temperature range, and the maximum enhancement can reach to 51.37%, which provides an attractive possible strategy for thermal conductivity improvement for molten salt based PCM, which is expected applied in the concentrated solar power generation system.

Hierarchically doping calcium carbonate pellets for directly solar-driven high-temperature thermochemical energy storage

Ca-based thermochemical energy storage (TCES) system is one of the most promising energy storage techniques for the next generation concentrated solar power systems (CSP). However, it still suffers from low optical absorption, poor cycle stability, and limited energy storage density. Here, a hierarchically doping strategy is proposed to overcome above challenges and achieve high-performance energy storage under direct solar irradiation. Hierarchically doped calcium carbonate pellets, which are suitable for scalable applications, are successfully fabricated with Al-doped internal cores and Mn-rich external shells. The average solar absorptance achieves 87.15% with a 7.4% increase compared with traditionally homogeneous doping approaches. The energy storage density is still as high as 1143 kJ/kg after 20 cycles, which is enhanced by 16.6% over homogeneous counterparts. The underlying mechanism is that hierarchically doping increases contents of active CaCO3 inside pellets and absorption-enhanced substances on the outer surface simultaneously. This work presents a novel approach for the design of high-performance pellets for achieving scalable and efficient thermochemical energy storage under direct solar irradiation.

Performance improvement and investigation of radiation heat transfer of chloride salt as high-temperature heat storage medium

• Synthesis of carbon doped molten salt composites by reaction method. • High absorptivity material combined with translucent molten salt. • Research on radiation heat transfer based on Finite Element Method (FEM). • Molten salts exhibit good thermal conductivity and radiative properties. The development of solar phase change thermal storage technology is significant for the efficient use of energy. In this study, molten chloride salt was used as a high-temperature phase change thermal storage material to improve the heat transfer performance of the chloride salt by reacting citric acid with sodium chlorite to generate a flaky carbon morphology in the molten salt. The results indicated that the carbon generated by the reaction was uniformly distributed in the molten salt matrix, and the modified molten salt obtained a high latent heat of phase change with a maximum latent heat of phase change of 227.3 J·g –1 , which was 13.7% higher than that of the undoped molten salt, and the maximum thermal conductivity could reach 2.313 W·m –1 ·K –1 , which effectively improved the applicability range. In addition, the combination of ANSYS simulations and the constructed temperature measurement platform showed that the radiation heat transfer effectively improved the temperature distribution of the molten salt in the high-temperature stage. This study may promote the research of the heat transfer behavior of molten salt at high temperature and play an important role in concentrated solar power generation.

Self-assembly CuO surface decorated with NiAl2O4 for high-temperature thermochemical energy storage: Excellent performance and strong interaction mechanism

High-temperature thermochemical energy storage materials with high energy density is the key technical support for the third generation concentrated solar power plants equipped with advanced energy storage system. CuO/Cu2O redox couple is one of the most promising systems due to its low cost and high energy density, but its application is limited by poor reaction performance. Herein, the self-assembly CuO surface decorated with 15 wt% NiAl2O4 is prepared with excellent redox reversibility and ultralong lifespan. Its reaction rate is increased by 4.2 times with re-oxidation degree increasing from 46 % to 99.9 %. The thermochemical energy density of storage and release reach −772.726 kJ/kg and 764.655 kJ/kg, respectively. After 1000 cycles, the degree of reduction and oxidation reaction can keep 99.9 % and 98 %. The material characterization shows that NiAl2O4 are uniformly and firmly loaded on the surface of CuO/Cu2O, which significantly increases the sintering temperature and improves the reaction performance. DFT studies further confirm that NiAl2O4 has a high binding energy with CuO/Cu2O and can increase the formation energy of copper vacancy. The study reveals the anti-sintering modification mechanism of CuO/Cu2O by introducing NiAl2O4, which provides a solution toward sintering resistance of high-temperature thermochemical energy storage materials.