High-power vanadium redox flow batteries require graphite felt electrodes that simultaneously exhibit fast redox kinetics, efficient interfacial charge transfer, and long-term structural stability. Herein, we report a covalent interfacial anchoring strategy to construct N/S–GF@rGO composite electrodes through a hydroiodic acid-assisted reaction between sulfur-containing sites on N/S-doped graphite felt and epoxy groups on graphene oxide. The resulting C–S–C thioether linkages chemically integrate reduced graphene oxide nanosheets with graphite fibers, improving interfacial electronic coupling, wettability, and structural integrity. Spectroscopic characterizations and density functional theory calculations support the formation of C–S–C linkages and reveal their favorable thermodynamic stability and interfacial electronic interaction. Benefiting from this chemically anchored interface, the optimized N/S–GF@rGO–2 electrode delivers an energy efficiency of 87.1% at 300 mA cm-2and maintains 75.8% at 500 mA cm-2, together with a peak power density of 1274.1 mW cm-2 and stable operation over 2000 cycles. This work demonstrates that covalent interfacial anchoring is an effective electrode-engineering strategy for developing durable, high-power vanadium redox flow batteries.

To address high energy consumption and carbon emissions in industrial waste salt treatment, this paper proposes a solar-driven coupled system integrating a moving-bed pyrolysis reactor with waste heat recovery unit and MgCl2·6H2O thermochemical energy storage unit. 4E (Energy, Exergy, Economic, Environmental) analysis and multi-objective optimization are performed. Under spring equinox, the system achieves an effective thermal efficiency of 20.67%, with a cost only 17.58% of natural-gas-based pyrolysis and a carbon emission reduction rate of 98.47%. Parametric analysis reveals strong coupling effects: for example, increasing air velocity (Uair) in waste heat recovery unit from 6 to 14 m·s-1 reduces the waste salt outlet temperature from 414.36 K to 323.76 K, but decreases MgCl2·6H2O conversion rate (X) from 0.98 to 0.76. With the objectives of maximizing salt processing capacity, thermal efficiency, and heat storage power, multi-objective optimization yields optimal parameters for each direct normal irradiance (DNI) level. As DNI increases from 700 to 1100 W·m-2, optimal Usalt rises from 0.90 to 1.56 mm·s-1, Uair stabilizes at 7-10 m·s-1, and UTCM rises from 0.10 to 0.20 mm·s-1. This study provides a theoretical basis for solar-driven low-carbon waste salt valorization coupled with thermochemical energy storage.

High-power operation of vanadium redox flow batteries (VRFBs) is still limited by sluggish interfacial charge transfer, insufficient electrolyte wettability, and concentration polarization within porous carbon electrodes. Herein, an iodine-functionalized reduced graphene oxide/graphite felt electrode (GF@rGO-V) was prepared through hydroiodic acid vapor treatment to regulate the solid-liquid interface of graphite felt while retaining its three-dimensional porous framework. Structural and surface analyses indicate that HI vapor treatment produces a less compact iodine-containing rGO interface with improved electrolyte accessibility. Electrochemical measurements further reveal enhanced apparent ion transport and reduced charge-transfer resistance toward both VO2+/VO2+ and V2+/V3+ redox couples. Temperature-dependent impedance analysis shows that the apparent activation energy for the positive reaction decreases from 40.2 kJ mol-1 on pristine graphite felt to 23.7 kJ mol-1 on GF@rGO-V, suggesting a more favorable interfacial kinetic environment. As a result, the assembled VRFB delivers an energy efficiency of 82.2% at 400 mA cm-2, a peak power density of 1257.6 mW cm-2, and stable cycling over 1500 cycles at 400 mA cm-2. This work demonstrates an iodine-assisted interfacial engineering strategy for improving mass transport and charge-transfer kinetics in high-power aqueous flow batteries.

Antireflection coating (ARC) enhances optical absorption and power generation of photovoltaic (PV) cells. However, detailed parameter design studies for improving irradiation uniformity are scarce. The trade-off between absorbed power and irradiation uniformity needs to be explicitly balanced. This research developed a twodimensional optical model of a space PV cell with ARC to optimize both the nanostructure and macro distribution of ARC. Firstly, the importance of ARC for enhancing solar energy absorption was confirmed. The influence of nanostructure parameters on optical performance of both plane and Moth-eye ARC was investigated. An optimal thickness of 50 nm for plane ARC was found, and the superiority of the Moth-eye structure was demonstrated. Then, further optimization derived the best Moth-eye parameters (H = 988.18 nm, P = 461.84 nm, f = 0.5, d = 891.71 nm), achieving an average absorption of 0.91. The macro irradiation distribution was then analyzed, revealing nonuniformity with a uniform ARC structure. Finally, the macro irradiation distribution was designed by another optimization combining Artificial Neural Network (ANN) and Multi-Objective Particle Swarm Optimization (MOPSO), yielding a pareto front that balances both absorbed power and irradiation uniformity. The optimized design shows superior absorbed power (96.13 W/m), irradiation uniformity (0.39) and significant PV efficiency improvement (+5.70%).

The application of thermal storage units is one approach to mitigate the intermittency of clean energy, where heat transfer efficiency and thermal storage capacity are critical parameters. To enhance heat transfer and thermal storage performance, three models-Uniform-type, U-type, and V-type-were constructed, using NaNO3-KNO3-NaNO2 (7:53:40 wt%) as the phase change material (PCM). The impact of these different arrangements on the PCM melting process was investigated through computational fluid dynamics simulations. The results indicate that the model with the Uniform-type arrangement requires 91.76 min to achieve complete melting of the PCM. The optimal V-type arrangement achieved a phase change completion time of 45.16% relative to the Uniform-type arrangement with no significant increase in cost for the thermal storage unit component. After 40 min of thermal storage, its energy storage capacity reaches 24.14 & times; 103 kJ, which is 1.38 times that of the Uniform-type model. Mechanism analysis revealed that the temperature difference between the heat source and the PCM, along with their contact area, are two critical factors affecting the system's heat transfer efficiency. These findings provide a basis for the structural optimization of the thermal energy storage unit.

The efficient removal of organic impurities in waste salt is significant for its recycling and environmental protection. In present paper, a solar pyrolysis reactor is proposed by integrating the parabolic trough concentrator (PTC) and solar reactor (SR). The results demonstrate that organic impurities react completely in 1290.7 s, and the thermal efficiency is up to 89.90 % at the initial temperature of 293.15 K and the reactor radius of 32 mm. However, the temperature difference (Delta T) Delta T ) in reactor is over 110 K. Based on this, the effects of initial temperature and reactor radius on pyrolysis results are explored. To improve the uniformity of temperature distribution and pyrolysis performance, a new pitchfork-shaped fin has been designed. Compared with no fins, the Delta T and reaction time are reduced by 54.99 % and 24.36 %, and the thermal efficiency is improved by 6.47 %. In comparison to traditional star-shaped fins, the Delta T is reduced by 13.1 %. Then, to further enhance the comprehensive performance of pitchfork-shaped fins, optimization on fin structure parameters is performed and validated. After optimization, the Delta T and reaction time are further reduced by 10.27% and 2.3 %. The present work demonstrates that the PTC-SR is feasible for the efficient removal of organic impurities in waste salts, which is significant for the recycling and utilization of waste salt.

The reuse of industrial waste salts offers significant potential for environmental protection and resource conservation. This study investigates the application of industrial waste salt, primarily composed of magnesium chloride hexahydrate, as a thermochemical heat storage material. Expanded perlite was selected as the porous matrix to prepare composite materials, and comparative analyses were performed to evaluate the water adsorption, dehydration, and cyclic performance of waste salt and pure salt composite materials. Results indicate minimal differences in water adsorption and dehydration behavior between waste and pure salts. The heat storage density of pure salt and waste salt are 541 J·g-1 and 515 J·g-1, respectively. The both composite materials demonstrated a water adsorption capacity of approximately 1.0 g·g-1 within 24 h and complete dehydration within 4 h. Expanded perlite effectively mitigated deliquescence leakage during hydration, maintaining structural integrity. Additionally, the water adsorption rate increased with humidity. This study highlights that the thermochemical energy storage properties of waste salts are comparable to those of pure salts, making waste salts a cost-effective alternative for thermal storage material development. This approach provides a sustainable pathway for industrial waste salt reuse, eliminating the need for costly purification processes and supporting large-scale applications in energy storage systems.

Thermoelectric generator (TEG) plays an important role in waste heat utilization and clean power generation. However, the relationship between the structure and the safety temperature of TEG is ignored, and no research has been reported about the application of TEG in outer space. In this study, a three-dimension thermal-electrical-mechanical coupling model of TEG operating in outer space is established, and its electrical and mechanical performance is investigated. Firstly, three typical cases of TEG with different structure and operating temperature difference are compared, and the advantages (high efficiency and power density) and problem (high thermal stress) faced of TEG applied in outer space are illustrated. Then, the effects of structure and operation parameters of TEG on electrical and mechanical performance are analyzed. The design variables for TEG are determined and their interaction relationships is provided. In particular, a phenomenon that the copper strips tend to exceed failure limit more than other components is clearly pointed out. Finally, optimization on structure and operation parameters is performed, and the optimal case with a = 2.52 mm, h = 1.06 mm, RL = 0.010 Omega and Tc= 214.11 K is obtained and recommended. The optimal case has the maximum power density 175.73 W/kg, and its efficiency still has 5.17% ranking the third highest value among the comparison cases. The results in this research can provide a reference for the design of TEG with applications in outer space.

Thermochemical heat storage (TCHS) has the advantages of high energy density and low heat loss. In this study, parabolic trough concentrator (PTC) technology is combined with TCHS reactor. A numerical model of photothermal coupled energy storage process is established for PTC-TCHS. The fins of the reactor are designed by topology optimization method to reduce the temperature difference and improve the TCHS performance. Firstly, the effect of fin volume fraction on TCHS performance is analyzed, and the most reasonable fin volume fraction of 15 % is derived. After that, performance of the reactor with topological fins is compared with other empirically designed fins. The results show that the topological fins were effective in reducing the temperature difference by 37 %, 19.9 % and 8.5% compared to straight, horizontal and curved fins. Meanwhile, the topological fin has the shortest reaction time of 6980 s and the highest thermal efficiency of 76.7 %. Finally, the effects of different operating conditions of DNI and reactant porosity on the topological fin reactor are explored. Under different operating conditions, the topological fin reactor always has better applicability and superiority, which demonstrate the reliability of the topology optimization method for fin design of solar thermochemical heat storage reactor.

Chloride molten salts is considered as a promising heat storage material in next generation solar thermal power generation systems. However, their corrosive effects on alloys cannot be overlooked. In this paper, a 2D cellular automata (CA) corrosion model based on the corrosion mechanisms of Ni-based alloys in NaCl-KCl-MgCl2 molten salt is established, and the simulated evolution rules of the corrosion process are defined. Based on the model, the corrosion extent, the evolution of the internal structure, and the distribution of Cr elements are revealed and compared with experimental values. The effects of key parameters on corrosion rate are also investigated. The results show that corrosion rate is positively correlated with the concentrations of Cl2 and O2, and negatively correlated with the concentrations of Mg(OH)Cl, Cr and the main reaction probability Pr12. Orthogonal experiment results show that the influence order of parameters on corrosion rate in turn is the concentrations of Cl2, Mg (OH)Cl, O2, Cr, and Pr12. When the parameter takes the optimal value, the corrosion rate is 1.532 x 103 mu m/y, which is reduced by up to 17.7 % compared with the original conditions. This approach is applicable to studying the corrosion behavior of Ni-based alloys in NaCl-KCl-MgCl2 molten salts, and provides significant insights into the corrosion mechanisms of alloys.

Parabolic trough concentrator (PTC) can be used as heat source of solar pyrolysis reactor (SPR) to pyrolyze organic impurities in waste salt. However, the conventional PTC-SPR is prone to two significant issues, uneven energy flux distribution and excessive temperature difference (Delta T). To address those issues, this study proposes a novel SPR structure featuring two semi-circular tubes with a gap width of H. A design method for the secondary plane reflector is established and the effect of H on energy flux distribution is investigated. The optimal H of 50 mm is identified, improving energy flux uniformity by 30.36 % compared to the conventional design. Photo-thermal coupling and pyrolysis performance analyses confirm that H = 50 mm delivers optimal results: Delta T is reduced by 75.20 %, reaction completion time (tend) is shortened by 7.89 %, and thermal efficiency (eta T) is enhanced by 3.68 %. Furthermore, preheating the waste salt accentuates the advantages of the novel PTC-SPR. This work provides significant insights for designing and applying PTC-SPR systems for the removal of organic impurities from industrial waste salts.

Concentrated photovoltaic (CPV) has the superiority of high efficiency and low cost. But the waste heat generated in PV cell has great effect on its performance. To study and optimize the real time photoelectric conversion performance, a two-dimensional PV model was firstly established. The impacts of concentration ratio and PV temperature on efficiency were investigated, and the correlation was derived. Based on that, phase change material (PCM) was utilized to realize temperature control of PV cell and a three-dimensional transient model for CPV-PCM system was established. The impacts of geometric parameters on the transient and annual performance were evaluated under the real climate conditions. The results show that concentration ratio has significant impacts on both thermal and electrical performance, and there exists an optimal concentration ratio to maximize the PV efficiency. At last, the system structure was optimized by orthogonal experimental method with annual average efficiency as the target. The optimal parameters combination was derived with concentration ratio of 300, PCM layer height of 60 mm, and fin number of 7. The validation results show that after optimizing, the maximum PV temperatures in summer and autumn are reduced by 9.4 degrees C and 7.4 degrees C, respectively, and the annual average efficiency of the system is improved by 1.83%.

Low-temperature acid corrosion on flue gas heat exchanger surfaces seriously reduces the stability, safety, and economy of equipment operation. Efficient strategies are urgently required to improve the anti-corrosion performance of heat exchangers. In present paper, a three-dimensional heat and mass transfer model integrating the acid dew point, acid condensation rate, and solution concentration was developed to predict the corrosion characteristics on the surfaces of 3-D finned tube heat exchangers. Firstly, a comparative analysis of acid condensate characteristics for 3-D finned tubes with different configurations was performed. The results showed that the elliptical tube effectively improves the distribution uniformity of acid condensate rate and promotes anti-corrosion performance. Then, the effects of five operating parameters (gas temperature, gas velocity, water vapor concentration, acid vapor concentration and wall temperature) on overall corrosion characteristics were systematically examined in terms of acid dew point, condensation rate and solution concentration using single-factor and orthogonal analysis, and the effect order of each factor was determined. Furthermore, optimization analysis of anti-corrosion performance was conducted based on the orthogonal results, and the optimum working conditions (water vapor concentration below 11.8% and wall temperature of 347K to 355K) are recommended. This research can provide theoretical guidance for the anti-corrosion designation and optimization of 3-D finned tube exchangers.

The poor heat transfer performance significantly limits the reaction rate of hydrogen storage and release in metal hydrides reactors. In this work, the expanded graphite was used as high thermal conductivity materials (HTCMs), its optimal distribution in metal hydrides reactor was obtained by topology optimization method to enhance the heat transfer performance. Comparative studies on the hydrogen storage and release performance were conducted for the optimal HTCMs distribution model, uniform HTCMs distribution model, reconstructed model, and unimproved model to validate the optimization results. Finally, the effect of HTCMs contents was also studied. The results show that the optimization results shorten the hydrogen storage and release time by 32.3 % and 15.9 %, respectively, compared to the uniform distribution model. Besides, the proposed optimization scheme exhibits good performance under different HTCMs contents. When the content was set to 12 %, the optimized model reduces the hydrogen storage and release time by 28.5 % and 10.8 %, compared to the results of uniform distribution. The method and results of topology optimization have high reliability, and the HTCMs distribution designed by topology optimization has better hydrogen storage and release performance compared to original designs, it is widely applicable.

The efficient removal of organic impurities in waste salts is significant for their recycling and environmental protection. The pyrolysis process of organic impurities in waste salt was investigated by thermogravimetric experiment to analyze the reaction kinetics characteristics. The results indicate that the pyrolysis reaction temperature range for the present waste salt is between 641.15 K and 726.22 K. The activation energy is 177.59 kJ mol -1, and the pre-exponential factor is 2.98 x 1011 s-1. Based on this, a numerical model was established to investigate the pyrolysis performance of organic impurities in practical tubular reactor. The effects of configuration and operating parameters on reaction performance and energy consumption were revealed. It was discovered that increasing the heating rate and wall temperature can accelerate pyrolysis rate but results in higher energy consumption. To balance reaction time and energy consumption, the heating rate of 15 K/min and heating temperature of 773.15 K are recommended. The content of organic impurities and bed porosity have minimal impact on the reaction rate and energy consumption, indicating that the tubular reactor has wide applicability in various working conditions. Additionally, reducing bed porosity can improve the processing rate and daily processing capacity. This paper provides a method to analyze the pyrolysis performance of organic impurities in waste salt, which is significant for designing and selecting working conditions of practical reactor for waste salt treatment.

This study investigates the impact of porosity distribution on the hydrogen storage performance of metal hydride (MH) reactors through numerical simulations. Firstly, the effects of different porosities on heat and mass transfer characteristics during hydrogen adsorption and desorption processes were analyzed. The results indicate that with increasing porosity, the hydrogen storage and release rates improved, but the hydrogen storage density decreased. To enhance reactor performance while maintaining hydrogen storage density, the bed porosity distribution was optimized. The optimization results showed that the hydrogen storage and release times of the MH reactor were reduced by 57.15% and 29.70%, respectively, at the same hydrogen storage density. Moreover, the optimized structure exhibited excellent hydrogen storage and release performance under different operating conditions, demonstrating its potential advantages in practical applications.

With the development of electric vehicles, it is particularly important to develop an efficient battery thermal management (BTM) system to control the temperature of lithium batteries within the safe range. In this study, the heat production characteristics of square lithium iron phosphate batteries were studied, and phase change materials (PCMs) were applied to the thermal management of lithium batteries. The results show that the surface temperature of the lithium battery is higher near the electrode and lower away from the electrode, and the temperature increases with the increase of ambient temperature and discharge rate. In addition, copper -foam paraffin can reduce the battery surface temperature to 46.9 degrees C, which is 4.1 degrees C lower than pure paraffin. On this basis, according to the heat generation characteristics of the battery, the battery pack with air-cooled channel was designed to reduce the weight of PCM and accelerate the regeneration of PCM, which is conducive to the development of the endurance of electric vehicles. The experimental results show that the coupling of PCM cooling and air cooling has better thermal management effect. When the wind speed is 30 km/h, the maximum surface temperature of the battery is 43.0 degrees C, which is 3.9 degrees C lower than that of only PCM cooling, and the higher the wind speed, the lower the surface temperature of the battery. When the battery is fully discharged, the surface temperature of the battery can be reduced to 35 degrees C in only 80 min in the natural state.

Anti-reflection film (ARF) with nanostructure plays an important role in reducing surface reflectance and improving power generation performance of solar cells. However, the reduction of reflectance is over-concerned during the design process of ARF, while the actual electrical performance of solar cells caused by structure changes of ARF tends to be ignored. In present study, a two-dimension photo-electric coupling model of thin GaAs cell with moth-eye nanostructured ARF was established, and its optical and electrical performance were investigated. Firstly, the optical and electrical performance of GaAs cells with and without ARF were compared to illustrate the importance of ARF for GaAs cell. Then, the effects of nanostructure parameters of ARF on optical and electrical performance were investigated, and a significant variation of the maximum efficiency (Delta eta max = 1.35%) was observed. After that, the energy transmission process of two randomly sampled cases were comparatively analyzed to demonstrate that only taking the reflectance as evaluation index during the design process of ARF is unreasonable. The maximum electrical power output (Pmax) or efficiency (eta max) was recommended as the appropriate evaluation index. Finally, based on the proposed evaluation index, a multi-parameters optimization was performed for moth-eye structure ARF, and the optimal case was derived with h = 100 nm, W = 100 nm, f = 0.453 and d = 50 nm. The corresponding maximum efficiency is 25.31%, which is 4.82% higher than that of GaAs cell without ARF, and is even 0.22% higher than the maximum eta max in samples.

Thermophysical properties of composite phase change materials (PCMs) are influenced by the interfacial nanolayer. Molecular dynamics (MD) method is used to study the effect of interfacial nanolayer on thermophysical properties of silica-paraffin composite PCM. The simulation results show that the melting enthalpy is reduced from 197.9 J center dot g- 1 to 29.1 J center dot g- 1, and the thermal conductivity is enhanced from 0.142 W center dot m- 1 center dot K-1 to 0.268 W center dot m- 1 center dot K-1, when the silica thickness is increased from 0 to 15.0 angstrom. The interfacial nanolayer is observed in composite PCM, and its thickness increases with the increase of silica wall thickness. In the composite PCM with 7.0 angstrom silica wall, a loss of 62.9% in the melting enthalpy is observed, with 32.6% attributed to the silica mass and 30.3% attributed to the nanolayer. Based on that, a modified model is proposed to predict the melting enthalpy of composite PCMs by considering the effects of both silica mass fraction and nanolayer. To reveal the thermal conductivity enhancement mechanism, the total heat flux is decomposed into three terms (namely, kinetic energy term, potential energy term and interaction energy term). It is found that the interaction energy term has the largest contribution to the total heat flux. The presence of nanolayer strengths the interactions, leading to the thermal conductivity enhancement.

To efficiently utilize the aerodynamic heat of aircraft and achieve thermal protection effect, a thermophotovoltaic-composite phase change material -thermoelectric (TPV-CPCM-TE) hybrid system is proposed to convert aerodynamic heat into electricity. The effects of emitter thickness, CPCM thickness, EG mass fraction in CPCM and convective heat transfer coefficient at TE cold side (cabin inner wall surface) on the transient and average power generation performance of TPV cell, TE and the hybrid system and the TE cold side temperature are numerically analyzed. The results show that the power generation of TPV cell accounts for the bulk of the total power generation. The emitter thickness mainly affects the power generation performance and has limited impact on TE cold side temperature. With CPCM thickness increasing, the power output of TPV cell gradually increases, till to be stable. The EG mass fraction has the greatest effect on system performance, both the power outputs of TPV cell and TE are improved with EG mass fraction increasing. The convective heat transfer coefficient only affects TE performance and has little effect on total power generation performance. Comprehensively considering the power generation and thermal protect performance, the appropriate parameters are recommended with the emitter thickness of 6.7 mm, the CPCM thickness of 15 mm, the EG mass fraction of 0.175 and the convective heat transfer coefficient of 5 W/(m2 & sdot;K) respectively. The corresponding average power generation and efficiency of the hybrid system are up to 174.84 W/m2 and 4.00 %, respectively.