Efficient Utilization Of Solar Energy Research Articles

An Artificial Light-Harvesting System based on Supramolecular AIEgen Assembly.

Photosynthesis is a complex multi-step process in which light collection is the initial step of photosynthesis and plays an important role in the efficiency of solar energy utilization. In order to improve the utilization of sunlight, researchers have developed a variety of artificial light-harvesting system to simulate photosynthesis in nature. Here, we report a supramolecular self-assembly artificial light-harvesting system in aqueous solution. We modified β-CD with the donor molecule naphthalimide and adamantane with the tetraphenylethylene molecule which has aggregation-induced emission effects (AIE). By using fluorescent molecules with AIE, the self-quenching effect caused by aggregation in aqueous solution can be effectively avoided. Due to the host-guest interaction of β-CD and adamantane, nanoparticles with stable structure and uniform size can be spontaneously assembled in water. Because of the close distance and strong spectral overlap between naphthalimide and tetraphenylethylene, Förster resonance energy transfer (FRET) was realized, and artificial light-harvesting system was successfully constructed in aqueous solution. The light-harvesting system has a high energy transfer efficiency (ΦET). Therefore, this study provides a new strategy for constructing artificial light-harvesting system.

Optical performance of a solar dish concentrator formed by the same size mirror located on parabolic frame

Solar dish concentrator with low cost and meeting the flux distribution is always pursued for the efficient utilization of concentrated solar energy. This paper investigates the optical performance of a solar dish concentrator formed by using a number of identical square mirror units arranged on a parabolic surface frame. The manufacturing of the mirror surface of this concentrator requires only one kind of mold, which has the significant advantage of low-cost manufacturing. Three common types of mirror units including the parabolic mirror (focal length fm), spherical mirror (radius Rm) and plane mirror are considered. The influence of key geometric parameters including the mirror width d (250–750 mm) and dimensionless parameters such as f1/D, fm/f1 and Rm/f1 (f1 is the focal length of parabolic frame) on its optical performance indexes such as the focused spot size (i.e., intercept width w), average local concentrator ratio (LCR), peak LCR and flux uniformity is analyzed using ray-tracing method, and the correctness of optical model and concentrator optical function is verified by outdoor concentrating experiments. The results show that the concentrator composed of parabolic or spherical mirrors can easily obtain a small circular focusing spot with high LCR and the intercept width can be easily controlled within 200 mm, the peak LCR can reach 34457 (average LCR is 12898), and average LCR reaches 14794 (peak LCR is 29497) at the smallest spot with w = 38.4 mm, which can be a low-cost alternative to parabolic dish concentrator. The concentrator with plane mirrors are easier to obtain square focusing spots with excellent flux uniformity, w can be controlled from 180 to 380 mm and uniform LCR is between 100 and 1400, which is very suitable for concentrating photovoltaic field.

Vertically aligned aerogel with concaved surface topography coupled ordered channel enable efficient solar-driven desalination

Solar-driven desalination has been regarded as a promising energy-saving and sustainable strategy to address the serious freshwater shortage issue. However, its performance is restricted by low solar energy utilization efficiency, water transport, and serious salt deposition. Herein, an efficient solar-driven interfacial evaporator with high solar energy utilization efficiency, fast water transport and robust salt tolerance was developed, via constructing vertically aligned sodium alginate (SA) aerogel with concave surface topography coupled ordered water transport channel structure. Concaved reflecting valley surface was assembled with 3D hierarchical photothermal networks of 2D MXene synergistic 1D carbon nanotube to enhance light absorption capacity. Concaved surface topography with multiple reflective nanostructure (angle 45°, depth 1.5 cm) owns strong sunlight concentration performance, which effectively avoid the light loss and thus enhance the light-absorption over a broad spectrum (0.3–2.5 μm). In another way, hydrophilic SA aerogel with vertically aligned structure, which also provides ordered channels for fast water/vapor transport and high salt rejection ability via strong wicking and diffusion effect. Solar-driven interfacial evaporator with such unique concaved surface topography that coupled ordered valley channels exhibits excellent evaporation rate (2.81kg m−2h−1) and remarkable solar energy utilizing efficiency (98.52 %), while with excellent antibacterial ability during continuously desalination process. Solar-driven interfacial evaporator with unique concaved surface topography coupled ordered valley channels holds great potential in sustainable water purification and desalination.

Efficient solar utilization: Multifunctional solar absorber devices realize self-driven hydrogen production

Considered as one of the effective approaches to address the energy crisis and develop green and sustainable energy, the application of solar energy in multiple stages was investigated in this study. By designing a WS2/ZnIn2S4 heterojunction, a multifunctional coupling system based on interfacial water evaporation technology was constructed. In this system, the water evaporation rate was 1.67 kgꞏm−2ꞏh−1, and the photocatalytic degradation efficiency of rhodamine B reached 96.5 %. Moreover, the electric energy output from thermoelectric conversion was innovatively in situ applied for photocatalytic hydrogen production, which increased the photocatalytic hydrogen production efficiency by five times, with a hydrogen production rate of 40.3 μmolꞏcm−2ꞏh−1. This study successfully integrated thermoelectric power generation, photocatalytic hydrogen production, and photocatalytic degradation of dye wastewater into an advanced solar-driven interface evaporation system, enabling the simultaneous conversion of solar energy into multiple forms of energy, improving solar energy utilization efficiency, which was of great significance for promoting the practical application of solar energy.

Fluorescence spectra as an indicator of the influence of environmental conditions on fruit trees

Molecular fluorescence spectra determine possible structural changes of these molecules and provide data (by comparing them with absorption ones) on the efficiency of solar energy utilization. Fluorescence emission spectra provide information on the functionality of the photosynthetic apparatus by means of two bands red F690 and beyond red F735. The objective of the study is to highlight possible changes in the organization and operation of the photosynthetic apparatus, induced by different radiations, in the leaves, for a variety of pear (Santa Maria), based on the characteristics of the two bands of emitted fluorescence. The Santa Maria variety was studied in the period of June.

Facile preparation of a novel basalt fiber fabric-based photothermal material for high salinity wastewater treatment and solar interface evaporation

Solar-driven interfacial evaporation (SIE) is a sustainable, efficient, and environmentally friendly desalination technology. It has great potential for solving the shortage of clean water and environmental pollution that humanity faces. Nevertheless, low strength, inadequate efficiency, and complicated preparation process of photothermal materials continue to be primary barriers to achieving the widespread application of SIE technology. Therefore, in the present work, a low-cost and eco-friendly photothermal material was prepared successfully by using multi-walled carbon nanotubes (MWCNTs), sodium alginate (SA) hydrogel, and basalt fiber (BF) fabric for obtaining purified/drinking water from seawater/brackish water. The results indicated that newly developed MWCNTs-SA/BF fabric had better wettability, evaporation performance, and purification capability. The evaporation rate of MWCNTs-SA/BF evaporator using simulated high salinity seawater could reach 1.48 kg m−2h−1 and 2.5 kg m−2h−1, under 1 and 2 suns illumination, respectively, and solar energy utilization efficiency is 91.6 % under 1 sun irradiation. Additionally, cyclic evaporation test results show that fabrics are highly durable for long-term solar evaporation. Furthermore, an excellent water purification performance of MWCNTs-SA/BF fabrics was also demonstrated by evaluating the purity of water samples and determining the changes in the four major ions (Na+, K+, Ca2+, and Mg2+) in seawater before and after evaporation experiments. This work provides a simple, practical, and economical approach to preparing a novel BF fabric-based evaporator that utilizes abundant solar energy potential for large-scale desalination and wastewater treatment.

Hollow g-C3N4@Ag3PO4 Core-Shell Nanoreactor Loaded with Au Nanoparticles: Boosting Photothermal Catalysis in Confined Space.

Low solar energy utilization efficiency and serious charge recombination remain major challenges for photocatalytic systems. Herein, a hollow core-shell Au/g-C3N4@Ag3PO4 photothermal nanoreactor is successfully prepared by a two-step deposition method. Benefit from efficient spectral utilization and fast charge separation induced by the unique hollow core-shell heterostructure, the H2 evolution rate of Au/g-C3N4@Ag3PO4 is 16.9 times that of the pristine g-C3N4, and the degradation efficiency of tetracycline is increased by 88.1%. The enhanced catalytic performance can be attributed to the ordered charge movement on the hollow core-shell structure and a local high-temperature environment, which effectively accelerates the carrier separation and chemical reaction kinetics. This work highlights the important role of the space confinement effect in photothermal catalysis and provides a promising strategy for the development of the next generation of highly efficient photothermal catalysts.

La implanted band engineering of ZnO nanorods for enhanced photoelectrochemical water splitting performance

In the quest to improve photoelectrochemical water-splitting performance, we have doped lanthanum (La) in highly crystalline zinc oxide (ZnO) nanorods (NRs) using a facile and low-temperature hydrothermal route and successful substitution of La3+ at the Zn2+ site is confirmed from structural and chemical analysis. The tapered NRs morphology gained after La doping resulted in lower optical bandgap of 3.17 eV, enhanced visible light trapping, and multiphoton absorption, which assist in achieving good PEC activity. The La doping also offered higher Urbach energy (EU), subsidizing the number of oxygen vacancies. The UPS spectra show that La doping reduces conduction band energy level and endorses smooth charge transportation. The La-doped ZnO exhibits two times enhancement in photocurrent (1.54 mA·cm−2) compared to pristine ZnO (0.81 mA·cm−2). The higher applied bias to the photon conversion efficiency of ∼1.14% for La-doped ZnO confirms the efficient utilization of solar energy. The EIS measurements demonstrated reduction in charge transfer resistance with La-doping. Mott-Schottky analysis shows that La doping lowers the flat-band potential and enhances charge transportation, making it a potential photoanode for PEC water-splitting applications.

Stable Photo-Rechargeable Al Battery for Enhancing Energy Utilization.

Photovoltaic cells (PVs) are able to convert solar energy to electric energy, while energy storage devices are required to be equipped due to the fluctuations of sunlight. However, the electrical connection of PVs and energy storage devices leads to increased energy consumption, and thus energy storage ability and utilization efficiency are decreased. One of the solutions is to explore an integrated photoelectrochemical energy conversion-storage device. Up to date, the integrated photo-rechargeable Li-ion batteries often suffer from unstable photo-active materials and flammable electrolytes under illumination, with concerns in safety risks and limited lifetime. To address the critical issues, here a novel photo-rechargeable aluminum battery (PRAB) is designed with safe ionic liquid electrolytes and stable polyaniline photo-electrodes. The integrated PRAB presents stable operation with an enhanced reversible specific capacity ≈191% under illumination. Meanwhile, a simplified continuum model is established to provide rational guidance for designing electrode structures along with a charging/discharging strategy to meet the practical operation conditions. The as-designed PRAB presents an energy-saving efficiency ≈61.92% upon charging and an energy output increment ≈31.25% during discharging under illumination. The strategy of designing and fabricating stable and safe photo-rechargeable non-aqueous Al batteries highlights the pathway for substantially promoting the utilization efficiency of solar energy.

Schottky junction-mediated carrier separation in BiOBr/Ti3C2Tx van der Waals heterojunction photocatalyst for increased removal of Cr(VI) under visible-light

The photocatalytic removal of pollutants can integrate efficient solar energy utilization with wastewater treatment. Herein, we report a simple strategy to construct BiOBr/Ti3C2Tx composite photocatalysts consisting of self-assembled van der Waals (vdw) heterojunction structures containing Schottky junctions. The vdW interaction between BiOBr and Ti3C2Tx and the structural stability of the catalysts were validated by density functional theory (DFT) calculations and an ab initio molecular dynamic simulation (AIMD). Compared to BiOBr, the BiOBr/Ti3C2Tx composites exhibited an enhanced light absorption capability and photocurrent response, along with a lower carrier recombination rate and charge-transfer resistance. The BiOBr/Ti3C2Tx activity for the photoreduction of hexavalent chromium (Cr(VI)) under visible-light irradiation considerably surpassed that of the original BiOBr (53.9 %). Using the BTC-0.8 catalyst (with a Ti3C2Tx: BiOBr mass ratio of 0.8 %) optimal reduction efficiency (94.0 %) for Cr(VI) with a reaction rate approximately 3.5 times that of pure BiOBr. The BTC-0.8 catalyst was viable over a wide pH range and maintained an 83.9 % photoreduction rate after four cycling experiments. The exceptional photocatalytic ability of BiOBr/Ti3C2Tx was achieved because Ti3C2Tx served as an electron injection layer that separated photogenerated carriers. The Schottky junction constructed within the BiOBr/Ti3C2Tx vdW heterojunctions suppressed electron backflow, promoting carrier separation. The excellent photocatalytic performance and strong cyclic stability of BiOBr/Ti3C2Tx demonstrated the considerable application potential of this photocatalyst.

Reinforcing the efficiency of photocatalytic CO2 conversion with H2O vapor through the integration of photothermal Cu/C@Bi/C supported on 3D g-C3N4 under full-spectrum solar irradiation

Developing an efficient photocatalyst for CO2 conversion to chemical fuels that maximizes the utilization of solar energy, particularly near-infrared light, remains a persistent challenge. Meanwhile, it is difficult to suppress the H2 evolution during the photocatalytic process. Herein, Cu/C@Bi/C grafted on the surface of 3D g-C3N4 (NCN) can serve as a highly durable and active catalyst for photothermal synergistic catalytic CO2 reduction under full-spectrum solar irradiation in solid-liquid-gas three-phase interfaces, wherein the Cu/C@Bi/C serves as a harvesting-near-infrared light nanoreactor and an electron transport bridge for the enhancement of the interface local temperature and the efficient transfer of photoinduced electrons. As a result, the hybrid catalyst shows excellent photothermal catalytic activity of CO2 to CO (169.26 μmol·g−1·h−1) and CO2 to CH4 (1.94 μmol·g−1·h−1), outperforming the majority of the conventional photocatalysts, whereas the competitive reaction of H2 evolution can be inhibited. This study presents a feasible approach for the efficient utilization of solar energy by harnessing near-infrared light through nano-reactors, thereby providing a viable strategy for photothermal catalytic CO2 reduction.

(Ca0.25La0.5Dy0.25)CrO3 Ceramic Fiber@Biomass-Derived Carbon Aerogel with Enhanced Solute Transport Channels for Highly Efficient Solar Interface Evaporation.

The use of solar interface evaporation for seawater desalination or sewage treatment is an environmentally friendly and sustainable approach; however, achieving efficient solar energy utilization and ensuring the long-term stability of the evaporation devices are two major challenges for practical application. To address these issues, we developed a novel ceramic fiber@bioderived carbon composite aerogel with a continuous through-hole structure via electrospinning and freeze-casting methods. Specifically, an aerogel was prepared by incorporating perovskite oxide (Ca0.25La0.5Dy0.25)CrO3 ceramic fibers (CCFs) and amylopectin-derived carbon (ADC). The CCFs exhibited remarkable photothermal conversion efficiencies, and the ADC served as a connecting agent and imparted hydrophilicity to the aerogel due to its abundant oxygen-containing functional groups. After optimizing the composition and microstructure, the (Ca0.25La0.5Dy0.25)CrO3 ceramic fiber@biomass-derived carbon aerogel demonstrated remarkable properties, including efficient light absorption and rapid transport of water and solutes. Under 1 kW m-2 light intensity irradiation, this novel material exhibited a high temperature (48.3 °C), high evaporation rate (1.68 kg m-2 h-1), and impressive solar vapor conversion efficiency (91.6%). Moreover, it exhibited long-term stability in water evaporation even with highly concentrated salt solutions (25 wt%). Therefore, the (Ca0.25La0.5Dy0.25)CrO3 ceramic fiber@biomass-derived carbon aerogel holds great promise for various applications of solar interface evaporation.

Proposal of a parabolic-trough-oriented photo-thermo-reactor with coaxial baffles and dual-bed for high-efficient solar-driven hydrogen production from methanol steam reforming

A novel tubular photo-thermo-reactor with coaxial baffles and dual (photo-thermo- and thermo-) catalyst beds is proposed, integrated with the commercially-mature parabolic trough concentrators (EuroTrough ET-100 model) with high scalability for high-efficient H2 production from solar-driven methanol steam reforming. The optical-flow-thermal-chemical multiphysics coupled model, which incorporates the experimental data of photo-thermo-catalytic reaction kinetics, have been established to optimize the geometric and operational conditions of the proposed reactor. It is demonstrated that the systematic solar hydrogen production efficiency up to 21.2 % considering the pumping power and the solar-to-hydrogen efficiency up to 30.6 % without considering the energy cost have been achieved in the best case. The reason for the excellent performance is two-fold. On the one hand, the existence of coaxial baffles guides multiple penetrations of the gaseous reactants through the catalyst beds thus guarantees sufficient contact between them. On the other hand, the design of coaxial dual-bed guarantees cascaded utilizations of both photo-thermo-catalysis and thermo-catalysis thus realizes higher utilization efficiency of full-spectrum solar energy. Considering the compatibility to the commercially-mature optical concentrator, this work exemplifies a practically promising route of effective full-spectrum solar-to-chemical conversion.

Dynamic characteristics and control method of the solar-coal energy complementary system

The solar-coal energy complementary technology is an effective way to use solar energy for power generation. In this work, a 330 MW coal-fired power generation unit, with an integrated solar field system, was studied to improve solar energy utilization efficiency and control performance. The dynamic mathematical model of the system was established using a lumped parameter method; the maximum relative error was found to be less than 5 %. Different coupling methods for the solar thermal system and coal-fired power unit were studied, and the dynamic characteristics of the unit under different solar radiation intensities were obtained. Finally, a coordinated control system was proposed based on the multiscale decomposition of load commands. The results show that the new coordinated control system showed more flexibility and less fluctuation of power during regulation. It has the best control effect, with the integral of the absolute value of the error criterion reaching 890.8 and 795 in step and slope experiments, respectively, and the integral of time multiplied by the squared error criterion reaching 4.172 × 105 and 3.043 × 105, respectively. This study successfully demonstrates the effective use of solar-coal energy complementary technology and provides an important reference for future work.

Experimental and numerical study on photovoltaic thermoelectric heat storage system based on phase change temperature control

To improve the thermal and electrical performance of photovoltaic (PV) systems, a novel system was proposed, in which the PV panel, phase change material (PCM), thermoelectric (TE), and thermal collection devices (PV-PCM-TEG-T) were combined. The experimental device of the PV-PCM-TEG-T system was put up, and its electrical and thermal characteristic was experimentally studied by comparing it with the standard PV panel on the condition of 3-hour radiation and 3-hour non-radiation. A heat transfer numerical model of the PV-PCM-TEG-T system is established and verified by experiments. The comparison of the PV-PCM-TEG-T system and standard PV panel and the effects of PCM thicknesses, and melting temperatures on the temperature of photovoltaic devices were numerically analyzed in 24-hour operating conditions. The results show that under an experimental condition of 3-hour solar radiance of 800 W/m2 and 3-hour non-radiance, the novel system has better temperature control performance, which could increase the PV panel’s output power and power generation efficiency by 10.4 % and 1.9 % respectively. Under 24-hour simulation conditions, the temperature of the novel system is significantly lower than that of the standard PV panel, with a maximum temperature difference of 10.1 °C. The PV-PCM-TEG-T system with thicker PCM has the same temperature as the system with thinner PCM, but higher TE power generation. And the temperature control is better with the lower PCM melting point. This study has a good promoting effect on the efficient utilization of solar energy.

Performance analysis of a novel solar Linear Fresnel concentrator system based on spectral beam splitting

Photothermal and photovoltaic are the most common and commercialized ways of utilizing solar energy. However, they cannot use solar energy efficiently. SBS (spectral beam splitting) technology is an efficient solar energy utilization technology that can realize the full spectrum utilization of solar energy. The current work involved: (1) Proposing a SBS-LFCs (linear Fresnel concentrator system) based on spectral beam splitting. In this system, the SBS photovoltaic panel replaces the conventional linear Fresnel concentrator lens, which can realize photovoltaic and photothermal utilization at the same time; (2) Developing a spectral splitting thin films configuration using the Needle method whose transmittance is higher than 90% against 380 nm-1100 nm band range; (3) Designing the SBS photovoltaic panel structure. The cover glass surface is covered with a SBS thin film. The SBS photovoltaic panel replaces the concentrator lens of LFCs; (4) Taking four typical days as examples, the annual power generation of a SBS linear Fresnel focusing system was predicted. The outcome indicates that the total conversion efficiency of solar thermal power in the system is 23.8%, 23.5%, 23.5%, and 23.6% on the spring equinox, summer solstice, autumn equinox, and winter solstice, respectively. Compared to conventional monocrystalline silicon cells, the photoelectric conversion efficiency has been improved by 14.6%, 12.8%, 12.5%, and 14.1%, respectively.

High light utilization of double-layer InxGa1−xN heterojunction nanowire array photocathodes

We propose a photocathode structure based on InxGa1−xN heterojunction nanowire array to enhance solar energy utilization efficiency. Compared with single-component InGaN nanowires, heterojunction nanowires can achieve higher effective quantum efficiency through the introduction of built-in electric field. This means that it has higher actual performance than previous studies. The maximum effective quantum efficiency of 300 nm-300 nm In0.5Ga0.5N-In0.57Ga0.43N heterojunction nanowires can reach 40.8 % when the incident light is obliquely incident at an angle of 70°. In addition, the external electric field can significantly help the heterojunction nanowires maintain higher actual performance over a longer wavelength range. This research is expected to provide theoretical support for the development and performance improvement of high-performance solar photocathode.

Interface interaction mediated surface plasmon resonance enhancement promoted visible-light-driven CO2 reduction with water

The conversion of carbon dioxide (CO2) into fuel using solar energy holds significant promise. However, the inefficient use of light and poor production activity have hindered its development. Here, we propose a simple in situ annealing oxidation method by coating a layer of TiO2 outside TiN, a material with a favorable price and localized surface plasmon resonance (LSPR) effect, to create an L-TiNO composite. The yield of CO over L-TiNO (50.8 μmol g−1 h−1) is 56.4 times that over TiO2 (0.9 μmol g−1 h−1) under visible light irradiation in pure aqueous environment, with a selectivity of 95.98%. In-situ Fourier transform infrared (FTIR) measurements reflect the CO2-COOH*-CO conversion route happening on L-TiNO. Characterizations like the Kelvin probe force microscopy (KPFM) technique confirm the generation of built-in electric field, which facilitates efficient carrier separation and migration. Density functional theory (DFT) calculations support that L-TiNO with LSPR effect alters the shape of absorbed CO2 to facilitate generation COOH* via forming hydroxyl end group (Ti-OH) and promotes CO* desorption to CO(g). This work provides valuable insights into the coupling of plasmonic materials with semiconductors to achieve efficient solar energy utilization.

Solar photovoltaic-integrated energy storage system with a power electronic interface for operating a brushless DC drive-coupled agricultural load

Abstract This article describes the design and construction of a solar photovoltaic (SPV)-integrated energy storage system with a power electronics interface (PEI) for operating a Brushless DC (BLDC) drive coupled to agricultural loads. The proposed system is intended to make use of the electrical power available at under-utilized, pre-installed solar pumps used for irrigation. The PEI allows efficient energy management by charging and discharging depending on available solar power. The BLDC drive is a high-performance motor drive that requires a smooth and stable DC voltage. The bidirectional DC converter provides this while also allowing for efficient energy management between the battery and the solar PV system. The simulation results illustrate that the system is capable of efficiently managing energy between the battery and solar panels, providing a stable DC voltage to drive the BLDC motor. In addition to this, the results demonstrate the feasibility of integrating a solar system with a battery and BDC for driving BLDC in various agricultural applications. The experimental findings validate the simulation outcomes for the proposed setup implemented in pre-installed, untapped SPV systems. The system is able to provide a stable and efficient power source while also allowing for efficient energy management and utilization of solar energy.

A Mini Review on Sewage Sludge and Red Mud Recycling for Thermal Energy Storage

Sewage sludge and red mud, as common industrial waste, have become a research hotspot in the field of achieving carbon peaking and carbon neutrality, reducing carbon emissions, and solving environmental problems. However, their treatment and disposal have always been a difficult problem in the environmental field. Utilizing these two materials for thermal energy storage can not only improve energy utilization efficiency but also further reduce carbon emissions during their treatment process, providing a new approach for sustainable development in the industrial sector. This article summarizes the research progress for the resource recovery of sewage sludge and red mud for direct thermal energy recovery and composite phase change energy storage. After proper treatment, sludge and red mud can be directly used as energy storage materials. In addition, sludge and red mud can be combined with phase change materials to prepare composite materials with an excellent energy storage performance. This composite has broad application prospects in fields such as solar energy utilization and building energy efficiency. However, there are still some challenges and issues in this resource recovery and utilization, such as potential environmental pollution during the treatment process, the long-term stability of energy storage materials, and cost-effectiveness, which require further research and resolution. The purpose of this paper is to evaluate the potential of sewage sludge and red mud as energy storage materials, to explore their feasibility and advantages in practical applications, and to reveal the research progress, technical challenges, and future development directions of these two materials in the field of thermal energy storage.