The ineluctable introduction of lithium salt to polymer solid-state electrolytes incurs a compromise between strength,ionic conductivity,and thickness.Here,we propose Al_(2)O_(3)-coated polyimide(AO/PI)porous film as ...The ineluctable introduction of lithium salt to polymer solid-state electrolytes incurs a compromise between strength,ionic conductivity,and thickness.Here,we propose Al_(2)O_(3)-coated polyimide(AO/PI)porous film as a high-strength substrate to support fast-ion-conducting polymer-in-salt(PIS)solid-state electrolytes,aiming to suppress lithium dendrite growth and improve full-cell performance.The Al_(2)O_(3)coating layer not only refines the wettability of polyimide porous film to PIS,but also performs as a high modulus protective layer to suppress the growth of lithium dendrites.The resulting PI/AO@PIS exhibits a small thickness of only 35μm with an outstanding tensile strength of 11.3 MPa and Young's modulus of 537.6 MPa.In addition,the PI/AO@PIS delivers a high ionic conductivity of 0.1 m S/cm at 25°C.As a result,the PI/AO@PIS enables symmetric Li cells to achieve exceptional cyclability for over 1000 h at 0.1 m A/cm2without noticeable lithium dendrite formation.Moreover,the PI/AO@PIS-based LiFePO4||Li full cells demonstrate outstanding rate performance(125.7 m Ah/g at 5 C)and impressive cycling stability(96.1%capacity retention at 1 C after 200 cycles).This work highlights the efficacy of enhancing the mechanical properties of polymer matrices and extending cell performance through the incorporation of a dense inorganic interface layer.展开更多
Achieving broadband solar thermal absorption via dilute nanofluids is still a daunting challenge since the absorption peaks of common metal particles are usually located in the visible part of the radiation spectrum.T...Achieving broadband solar thermal absorption via dilute nanofluids is still a daunting challenge since the absorption peaks of common metal particles are usually located in the visible part of the radiation spectrum.This paper aims to present the results of experimental investigations on the thermal performance of heat pipe-type evacuated solar collectors.The experimented system consists of 15 tubes,providing the hot nanofluid to 100-L storage in a closed flow loop.The solar collector with a gross area of 2.1 m^(2)is part of the solar hot water test system located in Baghdad-Iraq.Al2O3 nanofluid at 0.5%volume concentration in water as working fluid was used in three flow rates of 3.3,6.6,and 10 L/min over two months,March and April.The experimental results indicated that maximum solar irradiation was 1070 and 1270 W/m^(2)in March and April,respectively.The maximum daily average of rate heat gain 11,270 and 12,040 W was recorded in March and April,respectively.In terms of the best operational flow rate,the system performs better at 3.3 L/min nanofluid flow rate.For the considered study period,the average monthly maximum energy efficiencies of the solar collector in March and April were 86%and 80%,respectively.展开更多
An Al2O3 dispersion strengthened(ADS)alloy with an ultra-high softening temperature of∼1200 K was fabricated by the in-situ internal oxidation and reduction methods.The evolution of the nanometer Al2O3 particles,grai...An Al2O3 dispersion strengthened(ADS)alloy with an ultra-high softening temperature of∼1200 K was fabricated by the in-situ internal oxidation and reduction methods.The evolution of the nanometer Al2O3 particles,grain size,and consequently the softening behavior of this ADS alloy,were investigated by conducting the annealing treatments in the range from 673 K to 1273 K for 60 min.These refined nanometer Al2O3 particles were found to be highly stable at elevated temperatures,leading to the high dislocation density and grain boundary stability of the matrix.The average grain size was found to increase extremely slowly from∼0.60μm to∼0.74μm with increasing annealing temperatures from 773 K to 1273 K.A criterion for grain boundaries migration and softening was established based on the competition between grain growth and pinning effect of Al2O3 particles.The strong pinning effect of Al2O3 particles was found when the grain size was between the lower limit(about 0.4-0.5μm)and upper limit(2.18μm).The occurrence of softening behavior was attributed to the rapid increase of the proportion of grains larger than the upper limit.A modified Hall-Petch relationship was established by introducing the integration of the grain size distribution,which can describe this correlation between softening behavior and the pinning effect of Al2O3 particles.The current study not only sheds light on the further understanding of the softening mechanism of ADS copper alloy but also provides a useful route for designing copper alloy with high softening resistance.展开更多
基金the financial support from the 261Project of MIIT and Natural Science Foundation of Jiangsu Province(No.BK20240179)。
文摘The ineluctable introduction of lithium salt to polymer solid-state electrolytes incurs a compromise between strength,ionic conductivity,and thickness.Here,we propose Al_(2)O_(3)-coated polyimide(AO/PI)porous film as a high-strength substrate to support fast-ion-conducting polymer-in-salt(PIS)solid-state electrolytes,aiming to suppress lithium dendrite growth and improve full-cell performance.The Al_(2)O_(3)coating layer not only refines the wettability of polyimide porous film to PIS,but also performs as a high modulus protective layer to suppress the growth of lithium dendrites.The resulting PI/AO@PIS exhibits a small thickness of only 35μm with an outstanding tensile strength of 11.3 MPa and Young's modulus of 537.6 MPa.In addition,the PI/AO@PIS delivers a high ionic conductivity of 0.1 m S/cm at 25°C.As a result,the PI/AO@PIS enables symmetric Li cells to achieve exceptional cyclability for over 1000 h at 0.1 m A/cm2without noticeable lithium dendrite formation.Moreover,the PI/AO@PIS-based LiFePO4||Li full cells demonstrate outstanding rate performance(125.7 m Ah/g at 5 C)and impressive cycling stability(96.1%capacity retention at 1 C after 200 cycles).This work highlights the efficacy of enhancing the mechanical properties of polymer matrices and extending cell performance through the incorporation of a dense inorganic interface layer.
基金The University of Technology,specifically the Department of Electromechanical Engineering,provided invaluable assistance during the experimental work,for which the authors are quite grateful.
文摘Achieving broadband solar thermal absorption via dilute nanofluids is still a daunting challenge since the absorption peaks of common metal particles are usually located in the visible part of the radiation spectrum.This paper aims to present the results of experimental investigations on the thermal performance of heat pipe-type evacuated solar collectors.The experimented system consists of 15 tubes,providing the hot nanofluid to 100-L storage in a closed flow loop.The solar collector with a gross area of 2.1 m^(2)is part of the solar hot water test system located in Baghdad-Iraq.Al2O3 nanofluid at 0.5%volume concentration in water as working fluid was used in three flow rates of 3.3,6.6,and 10 L/min over two months,March and April.The experimental results indicated that maximum solar irradiation was 1070 and 1270 W/m^(2)in March and April,respectively.The maximum daily average of rate heat gain 11,270 and 12,040 W was recorded in March and April,respectively.In terms of the best operational flow rate,the system performs better at 3.3 L/min nanofluid flow rate.For the considered study period,the average monthly maximum energy efficiencies of the solar collector in March and April were 86%and 80%,respectively.
基金financially supported by the National Key Research and Development Program of China(No.2020YFB0311101)the National Natural Science Foundation of China(Nos.92066205 and 92266301)+1 种基金the Natural Science Foundation for Distinguished Young Scholars of China(No.51925401)the Youth Foundation of National Natural Science Foundation China(No.52001020).
文摘An Al2O3 dispersion strengthened(ADS)alloy with an ultra-high softening temperature of∼1200 K was fabricated by the in-situ internal oxidation and reduction methods.The evolution of the nanometer Al2O3 particles,grain size,and consequently the softening behavior of this ADS alloy,were investigated by conducting the annealing treatments in the range from 673 K to 1273 K for 60 min.These refined nanometer Al2O3 particles were found to be highly stable at elevated temperatures,leading to the high dislocation density and grain boundary stability of the matrix.The average grain size was found to increase extremely slowly from∼0.60μm to∼0.74μm with increasing annealing temperatures from 773 K to 1273 K.A criterion for grain boundaries migration and softening was established based on the competition between grain growth and pinning effect of Al2O3 particles.The strong pinning effect of Al2O3 particles was found when the grain size was between the lower limit(about 0.4-0.5μm)and upper limit(2.18μm).The occurrence of softening behavior was attributed to the rapid increase of the proportion of grains larger than the upper limit.A modified Hall-Petch relationship was established by introducing the integration of the grain size distribution,which can describe this correlation between softening behavior and the pinning effect of Al2O3 particles.The current study not only sheds light on the further understanding of the softening mechanism of ADS copper alloy but also provides a useful route for designing copper alloy with high softening resistance.
