Nanofiber membranes(NFMs) have become attractive candidates for next-generation flexible transparent materials due to their exceptional flexibility and breathability. However, improving the transmittance of NFMs is a ...Nanofiber membranes(NFMs) have become attractive candidates for next-generation flexible transparent materials due to their exceptional flexibility and breathability. However, improving the transmittance of NFMs is a great challenge due to the enormous reflection and incredibly poor transmission generated by the nanofiber-air interface. In this research, we report a general strategy for the preparation of flexible temperature-responsive transparent(TRT) membranes,which achieves a rapid transformation of NFMs from opaque to highly transparent under a narrow temperature window. In this process, the phase change material eicosane is coated on the surface of the polyurethane nanofibers by electrospray technology. When the temperature rises to 37 ℃, eicosane rapidly completes the phase transition and establishes the light transmission path between the nanofibers, preventing light loss from reflection at the nanofiber-air interface. The resulting TRT membrane exhibits high transmittance(> 90%), and fast response(5 s). This study achieves the first TRT transition of NFMs, offering a general strategy for building highly transparent nanofiber materials, shaping the future of next-generation intelligent temperature monitoring, anti-counterfeiting measures, and other high-performance devices.展开更多
The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here...The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here,we introduced metal ions to induce the self-assembly of MXene nanosheets and achieve their ordered arrangement by combining suction filtration and rapid freezing.Subsequently,a series of MXene/K^(+)/paraffin wax(PW)phase change composites(PCCs)were obtained via vacuum impregnation in molten PW.The prepared MXene-based PCCs showed versatile applications from macroscale technologies,successfully transforming solar,electric,and magnetic energy into thermal energy stored as latent heat in the PCCs.Moreover,due to the absence of binder in the MXene-based aerogel,MK3@PW exhibits a prime solar-thermal conversion efficiency(98.4%).Notably,MK3@PW can further convert the collected heat energy into electric energy through thermoelectric equipment and realize favorable solar-thermal-electric conversion(producing 206 mV of voltage with light radiation intensity of 200 mw cm^(−2)).An excellent Joule heat performance(reaching 105℃with an input voltage of 2.5 V)and responsive magnetic-thermal conversion behavior(a charging time of 11.8 s can achieve a thermal insulation effect of 285 s)for contactless thermotherapy were also demonstrated by the MK3@PW.Specifically,as a result of the ordered arrangement of MXene nanosheet self-assembly induced by potassium ions,MK3@PW PCC exhibits a higher electromagnetic shielding efficiency value(57.7 dB)than pure MXene aerogel/PW PCC(29.8 dB)with the same MXene mass.This work presents an opportunity for the multi-scene response and practical application of PCMs that satisfy demand of next-generation multifunctional PCCs.展开更多
Phase change materials (PCMs) can be incorporated with low-cost minerals to synthesize composites for thermal energy storage in building applications.Stone coal (SC) after vanadium extraction treatment shows potential...Phase change materials (PCMs) can be incorporated with low-cost minerals to synthesize composites for thermal energy storage in building applications.Stone coal (SC) after vanadium extraction treatment shows potential for secondary utilization in composite preparation.We prepared SC-based composite PCMs with SC as a matrix,stearic acid (SA) as a PCM,and expanded graphite (EG) as an additive.The combined roasting and acid leaching treatment of raw SC was conducted to understand the effect of vanadium extraction on promoting loading capacity.Results showed that the combined treatment of roasting at 900℃ and leaching increased the SC loading of the composite by 6.2%by improving the specific surface area.The loading capacity and thermal conductivity of the composite obviously increased by 127%and 48.19%,respectively,due to the contribution of 3wt% EG.These data were supported by the high load of 66.69%and thermal conductivity of 0.59 W·m^(-1)·K-1of the designed composite.The obtained composite exhibited a phase change temperature of 52.17℃,melting latent heat of 121.5 J·g^(-1),and good chemical compatibility.The SC-based composite has prospects in building applications exploiting the secondary utilization of minerals.展开更多
Nowadays buildings contain innovative materials,materials from local resources,production surpluses and rapidly renewable natural resources.Phase Change Materials(PCM)are one such group of novel materials which reduce...Nowadays buildings contain innovative materials,materials from local resources,production surpluses and rapidly renewable natural resources.Phase Change Materials(PCM)are one such group of novel materials which reduce building energy consumption.With the wider availability of microencapsulated PCM,there is an opportunity to develop a new type of insulating materials,combinate PCM with traditional insulation materials for latent heat energy storage.These materials are typically flammable and are located on the interior wall finishing yet there has been no detailed assessment of their fire performance.In this research work prototypes of low-density insulating boards for indoor spaces from hemp shives using carbamide resin binder and cold pressing were studied.Bench-scale cone calorimeter tests were conducted to evaluate fire risk,with a focus on assessing material flammability properties and the influence of PCM on the results.In this research,the amount of smoke,heat release rate,effective heat of combustion,specific extinction coefficient,mass loss,carbon dioxide yield,specific loss factor,ignition time of hemp straws samples and samples of hemp straws with 10%and without PCM admixture were compared.There is a risk of flammability for PCM and their fire reaction has not been evaluated when incorporating PCM into interior wall finishing boards.The obtained results can be used by designers to balance the potential energy savings of using PCM with a more complete understanding and predictability of the associated fire risk when using the proposed boards.It also allows for appropriate risk mitigation strategies.展开更多
Thermal management has become a crucial problem for high-power-density equipment and devices.Phase change materials(PCMs)have great prospects in thermal management applications because of their large capacity of heat ...Thermal management has become a crucial problem for high-power-density equipment and devices.Phase change materials(PCMs)have great prospects in thermal management applications because of their large capacity of heat storage and isothermal behavior during phase transition.However,low intrinsic thermal conductivity,ease of leakage,and lack of flexibility severely limit their applications.Solving one of these problems often comes at the expense of other performance of the PCMs.In this work,we report core–sheath structured phase change nanocomposites(PCNs)with an aligned and interconnected boron nitride nanosheet network by combining coaxial electrospinning,electrostatic spraying,and hot-pressing.The advanced PCN films exhibit an ultrahigh thermal conductivity of 28.3 W m^(-1)K^(-1)at a low BNNS loading(i.e.,32 wt%),which thereby endows the PCNs with high enthalpy(>101 J g^(-1)),outstanding ductility(>40%)and improved fire retardancy.Therefore,our core–sheath strategies successfully balance the trade-off between thermal conductivity,flexibility,and phase change enthalpy of PCMs.Further,the PCNs provide powerful cooling solutions on 5G base station chips and thermoelectric generators,displaying promising thermal management applications on high-power-density equipment and thermoelectric conversion devices.展开更多
CaCl_(2)·6H_(2)O/expanded vermiculite shape stabilized phase change materials(CEV)was prepared by atmospheric impregnation method.Using gold mine tailings as aggregate of cemented paste backfill(CPB)material,the ...CaCl_(2)·6H_(2)O/expanded vermiculite shape stabilized phase change materials(CEV)was prepared by atmospheric impregnation method.Using gold mine tailings as aggregate of cemented paste backfill(CPB)material,the CPB with CEV added was prepared,and the specific heat capacity,thermal conductivity,and uniaxial compressive strength(UCS)of CPB with different cement-tailing ratios and CEV addition ratios were tested,the influence of the above variables on the thermal and mechanical properties of CPB was analyzed.The results show that the maximum encapsulation capacity of expanded vermiculite for CaCl_(2)·6H_(2)O is about 60%,and the melting and solidification enthalpies of CEV can reach 98.87 J/g and 97.56 J/g,respectively.For the CPB without CEV,the specific heat capacity,thermal conductivity,and UCS decrease with the decrease of cement-tailing ratio.For the CPB with CEV added,with the increase of CEV addition ratio,the specific heat capacity increases significantly,and the sensible heat storage capacity and latent heat storage capacity can be increased by at least 10.74%and 218.97%respectively after adding 12%CEV.However,the addition of CEV leads to the increase of pores,and the thermal conductivity and UCS both decrease with the increase of CEV addition.When cement-tailing ratio is 1:8 and 6%,9%,and 12%of CEV are added,the 28-days UCS of CPB is less than 1 MPa.Considering the heat storage capacity and cost price of backfill,the recommended proportion scheme of CPB material presents cement-tailing ratio of 1:6 and 12%CEV,and the most recommended heat storage/release temperature cycle range of CPB with added CEV is from 20 to 40℃.This work can provide theoretical basis for the utilization of heat storage backfill in green mines.展开更多
Microporous membranes of low-high density polyethylene and their blends were prepared bythermally-induced phase separation of polymer/long-aliphatic chain alcohol (diluent) mixtures.The microstructures of this particu...Microporous membranes of low-high density polyethylene and their blends were prepared bythermally-induced phase separation of polymer/long-aliphatic chain alcohol (diluent) mixtures.The microstructures of this particular membrane, which depends on the diluent properties,polymer concentration and cooling rate, were observed by scanning electron microscopy."Beehive-type,"leafy-like, and lacy porous structure morphologies can be formed,depending onthe blend composition and phase separation conditions, which were discussed by the polymer anddiluent crystallization processes.展开更多
At present,only a single modification method is adopted to improve the shortcomings of erythritol(ET)as a phase change material(PCM).Compared with a single modification method,the synergistic effect of multiple modifi...At present,only a single modification method is adopted to improve the shortcomings of erythritol(ET)as a phase change material(PCM).Compared with a single modification method,the synergistic effect of multiple modification methods can endow ET with comprehensive performance to meet the purpose of package,supercooling reduction,and enhancement of thermal conductivity.In this work,we innovatively combine graphene oxide(GO)nanosheet modified melamine foam(MF)and polyaniline(PANI)to construct a novel ET-based PCM by blending and porous material adsorption modification.PANI as the nucleation center can enhance the crystallization rate,thereby reducing the supercooling of ET.Meanwhile,GO@MF foam can not only be used as a porous support material to encapsulate ET but also as a heat conduction reinforcement to improve heat storage and release rate.As a result,the supercooling of GO@MF/PANI@ET(GMPET)composite PCM decreases from 91.2℃ of pure ET to 57.9℃ and its thermal conductivity(1.58 W·m^(-1)·K^(-1))is about three times higher than that of pure ET(0.57 W·m^(-1)·K^(-1)).Moreover,after being placed at 140℃ for 2 h,there is almost no ET leakage in the GMPET composite PCM,and the mass loss ratio is less than 0.75%.In addition,the GMPET composite PCM displays a high melting enthalpy of about 259 J·g^(-1) and a high initial mass loss temperature of about 198℃.Even after the 200th cycling test,the phase transition temperature and the latent heat storage capacity of the GMPET PCM all remain stable.This work offers an effective and promising strategy to design ET-based composite PCM for the field of energy storage.展开更多
Over the past half-century, plastic consumption has grown rapidly due to its versatility, low cost, and unrivaled functional properties. Among the diff erent implemented strategies for recycling waste plastics, pyroly...Over the past half-century, plastic consumption has grown rapidly due to its versatility, low cost, and unrivaled functional properties. Among the diff erent implemented strategies for recycling waste plastics, pyrolysis is deemed the most economical option. Currently, the wax obtained from the pyrolysis of waste plastics is mainly used as a feedstock to manufacture chemicals and fuels or added to asphalt for pavement construction, with no other applications of wax being reported. Herein, the thermal pyrolysis of three common waste polyolefin plastics: high-density polyethylene(HDPE), low-density polyethylene(LDPE), and polypropylene(PP), was conducted at 450 ℃. The waste plastics-derived waxes were characterized and studied for a potential new application: phase change materials(PCMs) for thermal energy storage(TES). Gas chromatography–mass spectrometry analysis showed that paraffin makes up most of the composition of HDPE and LDPE waxes, whereas PP wax contains a mixture of naphthene, isoparaffin, olefin, and paraffin. Diff erential scanning calorimetry(DSC) analysis indicated that HDPE and LDPE waxes have a peak melting temperature of 33.8 ℃ and 40.3 ℃, with a relatively high latent heat of 103.2 J/g and 88.3 J/g, respectively, whereas the PP wax was found to have almost negligible latent heat. Fourier transform infrared spectroscopy and DSC results revealed good chemical and thermal stability of HDPE and LDPE waxes after 100 cycles of thermal cycling. Performance evaluation of the waxes was also conducted using a thermal storage pad to understand their thermoregulation characteristics for TES applications.展开更多
Active control of surface plasmon polaritons(SPPs)is highly desired for nanophotonics.Here we employ a phase change material Ge_(2)Sb_(2)Te_(5)(GST)to actively manipulate the propagating direction of SPPs at the telec...Active control of surface plasmon polaritons(SPPs)is highly desired for nanophotonics.Here we employ a phase change material Ge_(2)Sb_(2)Te_(5)(GST)to actively manipulate the propagating direction of SPPs at the telecom wavelength.By utilizing the phase transition-induced refractive index change of GST,coupled with interference effects,a nanoantenna pair containing GST is designed to realize switchable one-way launching of SPPs.Devices based on the nanoantenna pairs are proposed to manipulate SPPs,including the direction tuning of SPP beams,switchable SPP focusing,and switchable cosine–Gauss SPP beam generating.Our design can be employed in compact optical circuits and photonics integration.展开更多
Cold chain transportation is currently a hot research topic.Since the traditional refrigeration methods lead to the consumption of large amounts of energy,the search for new energy storage materials is a major trend.I...Cold chain transportation is currently a hot research topic.Since the traditional refrigeration methods lead to the consumption of large amounts of energy,the search for new energy storage materials is a major trend.In the present contribution,n-dodecane/PMMA microencapsulated phase change materials were prepared by suspension polymerization for ice-temperature cold chain transportation and their preparation parameters were explored using the encapsulation ratio as optimization indicator.The results show that the n-dodecane-containing microcapsules have a maximum encapsulation ratio of 93.2%when using a core-to-wall ratio of 3:1,5%of emulsifier,30%of crosslinker,and 2000 rpm of emulsification speed.The phase transition temperature and enthalpy are-2℃and 195.9 kJ/kg,respectively.The microcapsules prepared with the optimized process parameters have good microscopic morphology,high energy storage efficiency,uniform particle size and good thermal stability,making them ideal materials for cold chain transportation.展开更多
Adopting organic phase change materials(PCMs) for the management of electronic devices is restricted by low thermal conductivity. In this paper, the composite PCMs are established by freeze-drying and vacuum impregnat...Adopting organic phase change materials(PCMs) for the management of electronic devices is restricted by low thermal conductivity. In this paper, the composite PCMs are established by freeze-drying and vacuum impregnation. Herein, polyethylene glycol(PEG) is induced as heat storage materials, boron nitride(BN) is embedded as filler stacking in an orderly fashion on the foam walls to improve thermal conductivity and sodium alginate(SA) is formed as supporting material to keep the shape of the composite stable. X-ray diffractometry, scanning electron microscopy-energy dispersive spectrometer, thermal gravimetric analysis, thermal conductivity meter, differential scanning calorimeter, and Fourier transform infrared were used to characterize the samples and thermal cycles were employed to measure the shape stability. The results exhibit the BN@SA/PEG composite PCMs have good chemical compatibility, stable morphology, and thermal stability. Due to the high porosity of foam, PEG endows the composite PCMs with high latent heat(149.11 and 141.59 J·g^(-1)). Simultaneously, BN@SA/PEG shows an excellent heat performance with high thermal conductivity(0.99 W·m^(-1)·K^(-1)), reusability, and shape stability, contributing the composite PCMs to application in the energy storage field. This study provides a strategy to manufacture flexible, long-serving, and shape-stable PCMs via introducing BN@SA foam as a storage framework, and these PCMs have great potential in thermal management in the electronic field.展开更多
Dining lampblack as a source of atmospheric pollution,urban residents had to spend a lot of economic costs all year round to solve its impact.However,traditional treatment methods often carry the risk of secondary pol...Dining lampblack as a source of atmospheric pollution,urban residents had to spend a lot of economic costs all year round to solve its impact.However,traditional treatment methods often carry the risk of secondary pollution.The use of phase change absorption solvent(PCAS)controlled by CO_(2)can effectively absorb the oily components in dining lampblack,and smoothly avoid the generation of secondary pollutants and squandering of resources.The reversibility of PCASs under CO_(2)control was explained by pH changes and macroscopic visualizations.The absorption effects of favorable absorbents and PCASs on dining lampblack were compared and analyzed.The fatty acid(FA)in the oil absorption mixture was desorbed by interacting with D230.The results of GC/MS analysis on the oil components separated by desorption showed that the desorption of PCASs was effective for these refractory oil components.FAs can be enriched and applied to the subsequent dining lampblack treatment link to realize the waste recycling.In addition,the absorption and desorption of oily components by PCASs were combined with the CO_(2)-controlled phase transformation of PCASs itself to achieve the absorption circulation of treating dining lampblack by using PCASs.展开更多
Ionic liquid(IL),1-butyl-3-methylimidazolium hexafluorophosphate([BMIM]PF6)as a new and environmentally friendly diluent was introduced to prepare poly(vinylidene fluoride)(PVDF)membranes via thermally induced phase s...Ionic liquid(IL),1-butyl-3-methylimidazolium hexafluorophosphate([BMIM]PF6)as a new and environmentally friendly diluent was introduced to prepare poly(vinylidene fluoride)(PVDF)membranes via thermally induced phase separation(TIPS).Phase diagram of PVDF/[BMIM]PF6 was measured.The effects of polymer concentration and quenching temperature on the morphologies,properties,and performances of the PVDF membranes were investigated.When the polymer concentration was 15 wt%,the pure water flux of the fabricated membrane was up to nearly 2000 L·m-2·h-1,along with adequate mechanical strength.With the increasing of PVDF concentration and quenching temperature,mean pore size and water permeability of the membrane decreased.SEM results showed that PVDF membranes manufactured by ionic liquid(BMIm PF6)presented spherulite structure.And the PVDF membranes were represented asβphase by XRD and FTIR characterization.It provides a new way to prepare PVDF membranes with piezoelectric properties.展开更多
The serpentine tube liquid cooling and composite PCM coupled cooling thermal management system is designed for 18650 cylindrical power batteries,with the maximum temperature and temperature difference of the power pac...The serpentine tube liquid cooling and composite PCM coupled cooling thermal management system is designed for 18650 cylindrical power batteries,with the maximum temperature and temperature difference of the power pack within the optimal temperature operating range as the target.The initial analysis of the battery pack at a 5C discharge rate,the influence of the single cell to cooling tube distance,the number of cooling tubes,inlet coolant temperature,the coolant flow rate,and other factors on the heat dissipation performance of the battery pack,initially determined a reasonable value for each design parameter.A control strategy is used to regulate the inlet flow rate and coolant temperature of the liquid cooling system in order to make full use of the latent heat of the composite PCM and reduce the pump’s energy consumption.The simulation results show that the maximum battery pack temperature of 309.8 K and the temperature difference of 4.6 K between individual cells with the control strategy are in the optimal temperature operating range of the power battery,and the utilization rate of the composite PCM is up to 90%.展开更多
Perovskite-type mixed protonic-electronic conducting membranes have attracted attention because of their ability to separate and purify hydrogen from a mixture of gases generated by industrial-scale steam reforming ba...Perovskite-type mixed protonic-electronic conducting membranes have attracted attention because of their ability to separate and purify hydrogen from a mixture of gases generated by industrial-scale steam reforming based on an ion diffusion mechanism.Exploring cost-effective membrane materials that can achieve both high H_(2) permeability and strong CO_(2)-tolerant chemical stability has been a major challenge for industrial applications.Herein,we constructed a triple phase(ceramic-metal-ceramic)membrane composed of a perovskite ceramic phase BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)(BZCYYb),Ni metal phase and a fluorite ceramic phase CeO_(2).Under H_(2) atmosphere,Ni metal in-situ exsolved from the oxide grains,and decorated the grain surface and boundary,thus the electronic conductivity and hydrogen separation performance can be promoted.The BZCYYbNi-CeO_(2)hybrid membrane achieved an exceptional hydrogen separation performance of 0.53 mL min^(-1)cm^(-2) at 800℃ under a 10 vol% H_(2) atmosphere,surpassing all other perovskite membranes reported to date.Furthermore,the CeO_(2) phase incorporated into the BZCYYb-Ni effectively improved the CO_(2)-tolerant chemical stability.The BZCYYbNi-CeO_(2) membrane exhibited outstanding long-term stability for at least 80 h at 700℃ under 10 vol%CO_(2)-10 vol%H_(2).The success of hybrid membrane construction creates a new direction for simultaneously improving their hydrogen separation performance and CO_(2) resistance stability.展开更多
A study is presented on the feasibility of an approach based on the combination of Phase Change Materials(PCM)with metal walls in container-type houses.This line of research finds its motivations in recent trends in t...A study is presented on the feasibility of an approach based on the combination of Phase Change Materials(PCM)with metal walls in container-type houses.This line of research finds its motivations in recent trends in the energy and building sectors about energy consumption reduction.Another important objective concerns possible improvements in the comfort provided by such houses during the summer period.The results obtained through numerical solution of the governing equations accounting for heat transfer and latent heat effects associated with the PCM show that the indoor temperature can be reduced with a varying degree of success depending on the considered conditions.展开更多
The work deals with the thermal behavior of a conventional partition wall incorporating a phase change material(PCM).The wall separates two environments with different thermal properties.The first one is conditioned,w...The work deals with the thermal behavior of a conventional partition wall incorporating a phase change material(PCM).The wall separates two environments with different thermal properties.The first one is conditioned,while the adjacent space is characterized by a temperature that changes sinusoidally in time.The effect of the PCM is assessed through a comparative analysis of the cases with and without PCM.The performances are evaluated in terms of dimensionless energy stored within the wall,comfort temperature and variations of these quantities as a function of the amount of PCM and its emplacement.展开更多
Vanadium flow batteries(VFBs)are considered ideal for grid-sc ale,long-duration energy storage applications owing to their decoupled output power and storage capacity,high safety,efficiency,and long cycle life.However...Vanadium flow batteries(VFBs)are considered ideal for grid-sc ale,long-duration energy storage applications owing to their decoupled output power and storage capacity,high safety,efficiency,and long cycle life.However,the widespread adoption of VFB s is hindered by the use of expensive Nafion membranes.Herein,we report a soft template-induced method to develop a porous polyvinylidene fluoride(PVDF)membrane for VFB applications.By incorporating water-soluble and flexible polyethylene glycol(PEG 400)as a soft template,we induced the aggregation of hydrophilic sulfonated poly(ether ether ketone),resulting in phase separation from the hydrophobic PVDF polymer during membrane formation.This process led to the creation of a porous PVDF membrane with controllable morphologies determined by the polyethylene glycol content in the cast solution.The optimized porous PVDF membrane enabled a stable VFB performance for 200 cycles at a current density of 80 mA/cm^(2),and the VFB exhibited a Coulombic efficiency of 95.2%and a voltage efficiency of 87.8%.These findings provide valuable insights for the development of highly stable membranes for VFB applications.展开更多
基金financially supported by National Key Research and Development Program of China (2022YFB3804903, 2022YFB3804900)the National Natural Science Foundation of China (No. 52273052)+2 种基金the Fundamental Research Funds for the Central Universities (No. 2232023Y01)the Program of Shanghai Academic/Technology Research Leader (No. 21XD1420100)the International Cooperation Fund of Science and Technology Commission of Shanghai Municipality (No. 21130750100)。
文摘Nanofiber membranes(NFMs) have become attractive candidates for next-generation flexible transparent materials due to their exceptional flexibility and breathability. However, improving the transmittance of NFMs is a great challenge due to the enormous reflection and incredibly poor transmission generated by the nanofiber-air interface. In this research, we report a general strategy for the preparation of flexible temperature-responsive transparent(TRT) membranes,which achieves a rapid transformation of NFMs from opaque to highly transparent under a narrow temperature window. In this process, the phase change material eicosane is coated on the surface of the polyurethane nanofibers by electrospray technology. When the temperature rises to 37 ℃, eicosane rapidly completes the phase transition and establishes the light transmission path between the nanofibers, preventing light loss from reflection at the nanofiber-air interface. The resulting TRT membrane exhibits high transmittance(> 90%), and fast response(5 s). This study achieves the first TRT transition of NFMs, offering a general strategy for building highly transparent nanofiber materials, shaping the future of next-generation intelligent temperature monitoring, anti-counterfeiting measures, and other high-performance devices.
基金the National Natural Science Foundation of China[grant numbers 52203038,52173036 and 52073107]the National Key Technology R&D Program of China[grant number 2022YFC3901904,2022YFC3901903,and 2020YFB1709301]the Central University Basic Research Fund of China[grant number 2021XXJS035].
文摘The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here,we introduced metal ions to induce the self-assembly of MXene nanosheets and achieve their ordered arrangement by combining suction filtration and rapid freezing.Subsequently,a series of MXene/K^(+)/paraffin wax(PW)phase change composites(PCCs)were obtained via vacuum impregnation in molten PW.The prepared MXene-based PCCs showed versatile applications from macroscale technologies,successfully transforming solar,electric,and magnetic energy into thermal energy stored as latent heat in the PCCs.Moreover,due to the absence of binder in the MXene-based aerogel,MK3@PW exhibits a prime solar-thermal conversion efficiency(98.4%).Notably,MK3@PW can further convert the collected heat energy into electric energy through thermoelectric equipment and realize favorable solar-thermal-electric conversion(producing 206 mV of voltage with light radiation intensity of 200 mw cm^(−2)).An excellent Joule heat performance(reaching 105℃with an input voltage of 2.5 V)and responsive magnetic-thermal conversion behavior(a charging time of 11.8 s can achieve a thermal insulation effect of 285 s)for contactless thermotherapy were also demonstrated by the MK3@PW.Specifically,as a result of the ordered arrangement of MXene nanosheet self-assembly induced by potassium ions,MK3@PW PCC exhibits a higher electromagnetic shielding efficiency value(57.7 dB)than pure MXene aerogel/PW PCC(29.8 dB)with the same MXene mass.This work presents an opportunity for the multi-scene response and practical application of PCMs that satisfy demand of next-generation multifunctional PCCs.
基金financially supported by the National Natural Science Foundation of China, China (Nos. 52274252 and 51874047)the Special Fund for the Construction of Innovative Provinces in Hunan Province, China (No. 2020RC3038)the Changsha City Fund for Distinguished and Innovative Young Scholars, China (No. kq1802007)。
文摘Phase change materials (PCMs) can be incorporated with low-cost minerals to synthesize composites for thermal energy storage in building applications.Stone coal (SC) after vanadium extraction treatment shows potential for secondary utilization in composite preparation.We prepared SC-based composite PCMs with SC as a matrix,stearic acid (SA) as a PCM,and expanded graphite (EG) as an additive.The combined roasting and acid leaching treatment of raw SC was conducted to understand the effect of vanadium extraction on promoting loading capacity.Results showed that the combined treatment of roasting at 900℃ and leaching increased the SC loading of the composite by 6.2%by improving the specific surface area.The loading capacity and thermal conductivity of the composite obviously increased by 127%and 48.19%,respectively,due to the contribution of 3wt% EG.These data were supported by the high load of 66.69%and thermal conductivity of 0.59 W·m^(-1)·K-1of the designed composite.The obtained composite exhibited a phase change temperature of 52.17℃,melting latent heat of 121.5 J·g^(-1),and good chemical compatibility.The SC-based composite has prospects in building applications exploiting the secondary utilization of minerals.
基金supported by the European Regional Development Fund Postdoctoral Research Support“Structures and Technology Development of Smart Insulation Materials for Indoor Microclimate Regulation”1.1.1.2/VIAA/1/16/152the European Social Fund within the Project“Development of the Academic Personnel of Riga Technical University in the Strategic Fields of Specialization”Nr.8.2.2.0/18/A/017.
文摘Nowadays buildings contain innovative materials,materials from local resources,production surpluses and rapidly renewable natural resources.Phase Change Materials(PCM)are one such group of novel materials which reduce building energy consumption.With the wider availability of microencapsulated PCM,there is an opportunity to develop a new type of insulating materials,combinate PCM with traditional insulation materials for latent heat energy storage.These materials are typically flammable and are located on the interior wall finishing yet there has been no detailed assessment of their fire performance.In this research work prototypes of low-density insulating boards for indoor spaces from hemp shives using carbamide resin binder and cold pressing were studied.Bench-scale cone calorimeter tests were conducted to evaluate fire risk,with a focus on assessing material flammability properties and the influence of PCM on the results.In this research,the amount of smoke,heat release rate,effective heat of combustion,specific extinction coefficient,mass loss,carbon dioxide yield,specific loss factor,ignition time of hemp straws samples and samples of hemp straws with 10%and without PCM admixture were compared.There is a risk of flammability for PCM and their fire reaction has not been evaluated when incorporating PCM into interior wall finishing boards.The obtained results can be used by designers to balance the potential energy savings of using PCM with a more complete understanding and predictability of the associated fire risk when using the proposed boards.It also allows for appropriate risk mitigation strategies.
基金financially National Natural Science Foundation of China(51877132)Joint Funds of National Natural Science Foundation of China(U19A20105)the Program of Shanghai Academic Research Leader(No.21XD1401600)。
文摘Thermal management has become a crucial problem for high-power-density equipment and devices.Phase change materials(PCMs)have great prospects in thermal management applications because of their large capacity of heat storage and isothermal behavior during phase transition.However,low intrinsic thermal conductivity,ease of leakage,and lack of flexibility severely limit their applications.Solving one of these problems often comes at the expense of other performance of the PCMs.In this work,we report core–sheath structured phase change nanocomposites(PCNs)with an aligned and interconnected boron nitride nanosheet network by combining coaxial electrospinning,electrostatic spraying,and hot-pressing.The advanced PCN films exhibit an ultrahigh thermal conductivity of 28.3 W m^(-1)K^(-1)at a low BNNS loading(i.e.,32 wt%),which thereby endows the PCNs with high enthalpy(>101 J g^(-1)),outstanding ductility(>40%)and improved fire retardancy.Therefore,our core–sheath strategies successfully balance the trade-off between thermal conductivity,flexibility,and phase change enthalpy of PCMs.Further,the PCNs provide powerful cooling solutions on 5G base station chips and thermoelectric generators,displaying promising thermal management applications on high-power-density equipment and thermoelectric conversion devices.
基金supported by the National Natural Science Foundation of China(Nos.51974225,51874229,51674188,51904224,51904225)the Shaanxi Innovative Talents Cultivate Program-New-star Plan of Science and Technology,China(No.2018KJXX-083)+2 种基金the Natural Science Basic Research Plan of Shaanxi Province of China(Nos.2018JM 5161,2018JQ5183,2019JM-074)the Scientific Research Program funded by the Shaanxi Provincial Education Department,China(No.19JK0543)the Outstanding Youth Science Fund of Xi’an University of Science and Technology,China(No.2018YQ2-01)。
文摘CaCl_(2)·6H_(2)O/expanded vermiculite shape stabilized phase change materials(CEV)was prepared by atmospheric impregnation method.Using gold mine tailings as aggregate of cemented paste backfill(CPB)material,the CPB with CEV added was prepared,and the specific heat capacity,thermal conductivity,and uniaxial compressive strength(UCS)of CPB with different cement-tailing ratios and CEV addition ratios were tested,the influence of the above variables on the thermal and mechanical properties of CPB was analyzed.The results show that the maximum encapsulation capacity of expanded vermiculite for CaCl_(2)·6H_(2)O is about 60%,and the melting and solidification enthalpies of CEV can reach 98.87 J/g and 97.56 J/g,respectively.For the CPB without CEV,the specific heat capacity,thermal conductivity,and UCS decrease with the decrease of cement-tailing ratio.For the CPB with CEV added,with the increase of CEV addition ratio,the specific heat capacity increases significantly,and the sensible heat storage capacity and latent heat storage capacity can be increased by at least 10.74%and 218.97%respectively after adding 12%CEV.However,the addition of CEV leads to the increase of pores,and the thermal conductivity and UCS both decrease with the increase of CEV addition.When cement-tailing ratio is 1:8 and 6%,9%,and 12%of CEV are added,the 28-days UCS of CPB is less than 1 MPa.Considering the heat storage capacity and cost price of backfill,the recommended proportion scheme of CPB material presents cement-tailing ratio of 1:6 and 12%CEV,and the most recommended heat storage/release temperature cycle range of CPB with added CEV is from 20 to 40℃.This work can provide theoretical basis for the utilization of heat storage backfill in green mines.
文摘Microporous membranes of low-high density polyethylene and their blends were prepared bythermally-induced phase separation of polymer/long-aliphatic chain alcohol (diluent) mixtures.The microstructures of this particular membrane, which depends on the diluent properties,polymer concentration and cooling rate, were observed by scanning electron microscopy."Beehive-type,"leafy-like, and lacy porous structure morphologies can be formed,depending onthe blend composition and phase separation conditions, which were discussed by the polymer anddiluent crystallization processes.
基金supported by the State Key Laboratory of Advanced Power Transmission Technology(GEIRI-SKL-2021-014)。
文摘At present,only a single modification method is adopted to improve the shortcomings of erythritol(ET)as a phase change material(PCM).Compared with a single modification method,the synergistic effect of multiple modification methods can endow ET with comprehensive performance to meet the purpose of package,supercooling reduction,and enhancement of thermal conductivity.In this work,we innovatively combine graphene oxide(GO)nanosheet modified melamine foam(MF)and polyaniline(PANI)to construct a novel ET-based PCM by blending and porous material adsorption modification.PANI as the nucleation center can enhance the crystallization rate,thereby reducing the supercooling of ET.Meanwhile,GO@MF foam can not only be used as a porous support material to encapsulate ET but also as a heat conduction reinforcement to improve heat storage and release rate.As a result,the supercooling of GO@MF/PANI@ET(GMPET)composite PCM decreases from 91.2℃ of pure ET to 57.9℃ and its thermal conductivity(1.58 W·m^(-1)·K^(-1))is about three times higher than that of pure ET(0.57 W·m^(-1)·K^(-1)).Moreover,after being placed at 140℃ for 2 h,there is almost no ET leakage in the GMPET composite PCM,and the mass loss ratio is less than 0.75%.In addition,the GMPET composite PCM displays a high melting enthalpy of about 259 J·g^(-1) and a high initial mass loss temperature of about 198℃.Even after the 200th cycling test,the phase transition temperature and the latent heat storage capacity of the GMPET PCM all remain stable.This work offers an effective and promising strategy to design ET-based composite PCM for the field of energy storage.
基金financial support from Individual Research Grant (Grant reference No.: A20E7c0109) of the Agency for Science,Technology and Research of Singapore (A*STAR)。
文摘Over the past half-century, plastic consumption has grown rapidly due to its versatility, low cost, and unrivaled functional properties. Among the diff erent implemented strategies for recycling waste plastics, pyrolysis is deemed the most economical option. Currently, the wax obtained from the pyrolysis of waste plastics is mainly used as a feedstock to manufacture chemicals and fuels or added to asphalt for pavement construction, with no other applications of wax being reported. Herein, the thermal pyrolysis of three common waste polyolefin plastics: high-density polyethylene(HDPE), low-density polyethylene(LDPE), and polypropylene(PP), was conducted at 450 ℃. The waste plastics-derived waxes were characterized and studied for a potential new application: phase change materials(PCMs) for thermal energy storage(TES). Gas chromatography–mass spectrometry analysis showed that paraffin makes up most of the composition of HDPE and LDPE waxes, whereas PP wax contains a mixture of naphthene, isoparaffin, olefin, and paraffin. Diff erential scanning calorimetry(DSC) analysis indicated that HDPE and LDPE waxes have a peak melting temperature of 33.8 ℃ and 40.3 ℃, with a relatively high latent heat of 103.2 J/g and 88.3 J/g, respectively, whereas the PP wax was found to have almost negligible latent heat. Fourier transform infrared spectroscopy and DSC results revealed good chemical and thermal stability of HDPE and LDPE waxes after 100 cycles of thermal cycling. Performance evaluation of the waxes was also conducted using a thermal storage pad to understand their thermoregulation characteristics for TES applications.
文摘Active control of surface plasmon polaritons(SPPs)is highly desired for nanophotonics.Here we employ a phase change material Ge_(2)Sb_(2)Te_(5)(GST)to actively manipulate the propagating direction of SPPs at the telecom wavelength.By utilizing the phase transition-induced refractive index change of GST,coupled with interference effects,a nanoantenna pair containing GST is designed to realize switchable one-way launching of SPPs.Devices based on the nanoantenna pairs are proposed to manipulate SPPs,including the direction tuning of SPP beams,switchable SPP focusing,and switchable cosine–Gauss SPP beam generating.Our design can be employed in compact optical circuits and photonics integration.
基金supported by the National Key Research and Development Program of china(No.2018YFD1101005)and the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Cold chain transportation is currently a hot research topic.Since the traditional refrigeration methods lead to the consumption of large amounts of energy,the search for new energy storage materials is a major trend.In the present contribution,n-dodecane/PMMA microencapsulated phase change materials were prepared by suspension polymerization for ice-temperature cold chain transportation and their preparation parameters were explored using the encapsulation ratio as optimization indicator.The results show that the n-dodecane-containing microcapsules have a maximum encapsulation ratio of 93.2%when using a core-to-wall ratio of 3:1,5%of emulsifier,30%of crosslinker,and 2000 rpm of emulsification speed.The phase transition temperature and enthalpy are-2℃and 195.9 kJ/kg,respectively.The microcapsules prepared with the optimized process parameters have good microscopic morphology,high energy storage efficiency,uniform particle size and good thermal stability,making them ideal materials for cold chain transportation.
基金supported by the State Key Laboratory of Advanced Power Transmission Technology (GEIRI-SKL-2021-014)。
文摘Adopting organic phase change materials(PCMs) for the management of electronic devices is restricted by low thermal conductivity. In this paper, the composite PCMs are established by freeze-drying and vacuum impregnation. Herein, polyethylene glycol(PEG) is induced as heat storage materials, boron nitride(BN) is embedded as filler stacking in an orderly fashion on the foam walls to improve thermal conductivity and sodium alginate(SA) is formed as supporting material to keep the shape of the composite stable. X-ray diffractometry, scanning electron microscopy-energy dispersive spectrometer, thermal gravimetric analysis, thermal conductivity meter, differential scanning calorimeter, and Fourier transform infrared were used to characterize the samples and thermal cycles were employed to measure the shape stability. The results exhibit the BN@SA/PEG composite PCMs have good chemical compatibility, stable morphology, and thermal stability. Due to the high porosity of foam, PEG endows the composite PCMs with high latent heat(149.11 and 141.59 J·g^(-1)). Simultaneously, BN@SA/PEG shows an excellent heat performance with high thermal conductivity(0.99 W·m^(-1)·K^(-1)), reusability, and shape stability, contributing the composite PCMs to application in the energy storage field. This study provides a strategy to manufacture flexible, long-serving, and shape-stable PCMs via introducing BN@SA foam as a storage framework, and these PCMs have great potential in thermal management in the electronic field.
基金supported by the Chengdu Science and Technology Project of the Chengdu Bureau of Science and Technology(2021-YF05-00194-SN)the Foundation of Department of Science and Technology of Sichuan Province(2022NSFSC0203)。
文摘Dining lampblack as a source of atmospheric pollution,urban residents had to spend a lot of economic costs all year round to solve its impact.However,traditional treatment methods often carry the risk of secondary pollution.The use of phase change absorption solvent(PCAS)controlled by CO_(2)can effectively absorb the oily components in dining lampblack,and smoothly avoid the generation of secondary pollutants and squandering of resources.The reversibility of PCASs under CO_(2)control was explained by pH changes and macroscopic visualizations.The absorption effects of favorable absorbents and PCASs on dining lampblack were compared and analyzed.The fatty acid(FA)in the oil absorption mixture was desorbed by interacting with D230.The results of GC/MS analysis on the oil components separated by desorption showed that the desorption of PCASs was effective for these refractory oil components.FAs can be enriched and applied to the subsequent dining lampblack treatment link to realize the waste recycling.In addition,the absorption and desorption of oily components by PCASs were combined with the CO_(2)-controlled phase transformation of PCASs itself to achieve the absorption circulation of treating dining lampblack by using PCASs.
基金the financial support of the National Natural Science Foundation of China(Grant No.21606125)the Natural Science Foundation of Jiangsu Province(Grant No.BK20160984)+3 种基金the National Key R&D Program of China(Grant No.2017YFC0403702)the Materials-Oriented Chemical Engineering State Key Laboratory Program(KL16-09)the open project program of Jiangsu Key Lab for Chemistry of Low-Dimensional Materials(JSKC17005)the Priority Academic Program Development of Jiangsu Higher Education Institution(PAPD)。
文摘Ionic liquid(IL),1-butyl-3-methylimidazolium hexafluorophosphate([BMIM]PF6)as a new and environmentally friendly diluent was introduced to prepare poly(vinylidene fluoride)(PVDF)membranes via thermally induced phase separation(TIPS).Phase diagram of PVDF/[BMIM]PF6 was measured.The effects of polymer concentration and quenching temperature on the morphologies,properties,and performances of the PVDF membranes were investigated.When the polymer concentration was 15 wt%,the pure water flux of the fabricated membrane was up to nearly 2000 L·m-2·h-1,along with adequate mechanical strength.With the increasing of PVDF concentration and quenching temperature,mean pore size and water permeability of the membrane decreased.SEM results showed that PVDF membranes manufactured by ionic liquid(BMIm PF6)presented spherulite structure.And the PVDF membranes were represented asβphase by XRD and FTIR characterization.It provides a new way to prepare PVDF membranes with piezoelectric properties.
基金support provided National Natural Science Foundation of China with Grant No.51976016Natural Science Foundation of Hunan Province,China with Grant No.2020JJ4616Research Foundation of Education Bureau of Hunan Province(18B149).
文摘The serpentine tube liquid cooling and composite PCM coupled cooling thermal management system is designed for 18650 cylindrical power batteries,with the maximum temperature and temperature difference of the power pack within the optimal temperature operating range as the target.The initial analysis of the battery pack at a 5C discharge rate,the influence of the single cell to cooling tube distance,the number of cooling tubes,inlet coolant temperature,the coolant flow rate,and other factors on the heat dissipation performance of the battery pack,initially determined a reasonable value for each design parameter.A control strategy is used to regulate the inlet flow rate and coolant temperature of the liquid cooling system in order to make full use of the latent heat of the composite PCM and reduce the pump’s energy consumption.The simulation results show that the maximum battery pack temperature of 309.8 K and the temperature difference of 4.6 K between individual cells with the control strategy are in the optimal temperature operating range of the power battery,and the utilization rate of the composite PCM is up to 90%.
基金financially supported by the National Key R&D Program of China(2021YFA1502400)the"Transformational Technologies for Clean Energy and Demonstration"+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA2100000)the National Natural Science Foundation of China(52172005,21905295,22179141)the DNL Cooperation Fund,CAS(DNL202008)the Photon Science Center for Carbon Neutrality and the Major Scientific and Technological Innovation Project of Shandong Province(2020CXGC010402)。
文摘Perovskite-type mixed protonic-electronic conducting membranes have attracted attention because of their ability to separate and purify hydrogen from a mixture of gases generated by industrial-scale steam reforming based on an ion diffusion mechanism.Exploring cost-effective membrane materials that can achieve both high H_(2) permeability and strong CO_(2)-tolerant chemical stability has been a major challenge for industrial applications.Herein,we constructed a triple phase(ceramic-metal-ceramic)membrane composed of a perovskite ceramic phase BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)(BZCYYb),Ni metal phase and a fluorite ceramic phase CeO_(2).Under H_(2) atmosphere,Ni metal in-situ exsolved from the oxide grains,and decorated the grain surface and boundary,thus the electronic conductivity and hydrogen separation performance can be promoted.The BZCYYbNi-CeO_(2)hybrid membrane achieved an exceptional hydrogen separation performance of 0.53 mL min^(-1)cm^(-2) at 800℃ under a 10 vol% H_(2) atmosphere,surpassing all other perovskite membranes reported to date.Furthermore,the CeO_(2) phase incorporated into the BZCYYb-Ni effectively improved the CO_(2)-tolerant chemical stability.The BZCYYbNi-CeO_(2) membrane exhibited outstanding long-term stability for at least 80 h at 700℃ under 10 vol%CO_(2)-10 vol%H_(2).The success of hybrid membrane construction creates a new direction for simultaneously improving their hydrogen separation performance and CO_(2) resistance stability.
文摘A study is presented on the feasibility of an approach based on the combination of Phase Change Materials(PCM)with metal walls in container-type houses.This line of research finds its motivations in recent trends in the energy and building sectors about energy consumption reduction.Another important objective concerns possible improvements in the comfort provided by such houses during the summer period.The results obtained through numerical solution of the governing equations accounting for heat transfer and latent heat effects associated with the PCM show that the indoor temperature can be reduced with a varying degree of success depending on the considered conditions.
文摘The work deals with the thermal behavior of a conventional partition wall incorporating a phase change material(PCM).The wall separates two environments with different thermal properties.The first one is conditioned,while the adjacent space is characterized by a temperature that changes sinusoidally in time.The effect of the PCM is assessed through a comparative analysis of the cases with and without PCM.The performances are evaluated in terms of dimensionless energy stored within the wall,comfort temperature and variations of these quantities as a function of the amount of PCM and its emplacement.
基金financially supported by Open Fund of Material Corrosion and Protection Key Laboratory of Sichuan Province of China(No.2020CL09)Hunan Key Laboratory of Applied Environmental Photocatalysis(No.2214503)。
文摘Vanadium flow batteries(VFBs)are considered ideal for grid-sc ale,long-duration energy storage applications owing to their decoupled output power and storage capacity,high safety,efficiency,and long cycle life.However,the widespread adoption of VFB s is hindered by the use of expensive Nafion membranes.Herein,we report a soft template-induced method to develop a porous polyvinylidene fluoride(PVDF)membrane for VFB applications.By incorporating water-soluble and flexible polyethylene glycol(PEG 400)as a soft template,we induced the aggregation of hydrophilic sulfonated poly(ether ether ketone),resulting in phase separation from the hydrophobic PVDF polymer during membrane formation.This process led to the creation of a porous PVDF membrane with controllable morphologies determined by the polyethylene glycol content in the cast solution.The optimized porous PVDF membrane enabled a stable VFB performance for 200 cycles at a current density of 80 mA/cm^(2),and the VFB exhibited a Coulombic efficiency of 95.2%and a voltage efficiency of 87.8%.These findings provide valuable insights for the development of highly stable membranes for VFB applications.
