Phase change materials(PCMs)are an interesting technology due to their high density and isothermal behavior during phase change.Phase change material plays a major role in the energy saving of the buildings,which is g...Phase change materials(PCMs)are an interesting technology due to their high density and isothermal behavior during phase change.Phase change material plays a major role in the energy saving of the buildings,which is greatly aided by the incorporation of phase change material into building products such as bricks,cement,gypsum board,etc.In this study,an experiment has been conducted with three identical small chambers made up of normal,grooved and PCM-treated grooved bricks.Before the inclusion of PCM in grooved bricks,PCM material behavior has been studied by different techniques such as DSC,TG/DTA,SEM,and XRD.Thermal properties and thermal stability were investigated by differential scanning calorimeter(DSC)and thermogravimetric analyzer(TGA)respectively.Scanning electron microscopy(SEM)and X-ray diffraction(XRD)were used to determine the microstructure and crystalloid phase of the PCM before and after the accelerated thermal cycling test(0,60,120).These three identical model rooms built were exposed at a temperature just above 40°C with a heater.When the maximum outdoor temperature was 40-41°C,then the temperature of the PCM-treated grooved chamber was 32-33°C.The PCM-treated wall was tested and compared with a conventional and grooved wall.The difference between the PCM-treated grooved chamber and the untreated one was 8-9°C.PCM-treated bricks provided more efficient internal heat retention in summer when the outside temperature increased.展开更多
An active anode material for Li-ion batteries was synthesized using a simple mechanochemical process to minimize the large change in Si volume observed during charge-discharge operation and to compensate for the assoc...An active anode material for Li-ion batteries was synthesized using a simple mechanochemical process to minimize the large change in Si volume observed during charge-discharge operation and to compensate for the associated irreversible loss of Li or irreversible capacity loss, which are obstacles to achieve high-performance electrochemical properties during charge-discharge. The composite was mechanochemically milled with Si, lithium oxide, and copper oxide as raw materials;the composite contains Si nanoparticles, amorphous silicon monoxide, and Si-Li or Si-Cu alloy compounds, and it exhibits improved electrochemical properties. In particular, this composite achieved a better capacity retention, higher coulombic efficiency (over 100%), and longer cycling performance than Si alone, indicating considerable optimization of the electrical and ionic conductivity in the composite. The developed method allowed for control of the Li content to compensate for the lack of Li ions in the composite, and the cycling performance was optimized using the Cu alloy, oxide, and Li compounds within the composite.展开更多
文摘Phase change materials(PCMs)are an interesting technology due to their high density and isothermal behavior during phase change.Phase change material plays a major role in the energy saving of the buildings,which is greatly aided by the incorporation of phase change material into building products such as bricks,cement,gypsum board,etc.In this study,an experiment has been conducted with three identical small chambers made up of normal,grooved and PCM-treated grooved bricks.Before the inclusion of PCM in grooved bricks,PCM material behavior has been studied by different techniques such as DSC,TG/DTA,SEM,and XRD.Thermal properties and thermal stability were investigated by differential scanning calorimeter(DSC)and thermogravimetric analyzer(TGA)respectively.Scanning electron microscopy(SEM)and X-ray diffraction(XRD)were used to determine the microstructure and crystalloid phase of the PCM before and after the accelerated thermal cycling test(0,60,120).These three identical model rooms built were exposed at a temperature just above 40°C with a heater.When the maximum outdoor temperature was 40-41°C,then the temperature of the PCM-treated grooved chamber was 32-33°C.The PCM-treated wall was tested and compared with a conventional and grooved wall.The difference between the PCM-treated grooved chamber and the untreated one was 8-9°C.PCM-treated bricks provided more efficient internal heat retention in summer when the outside temperature increased.
文摘An active anode material for Li-ion batteries was synthesized using a simple mechanochemical process to minimize the large change in Si volume observed during charge-discharge operation and to compensate for the associated irreversible loss of Li or irreversible capacity loss, which are obstacles to achieve high-performance electrochemical properties during charge-discharge. The composite was mechanochemically milled with Si, lithium oxide, and copper oxide as raw materials;the composite contains Si nanoparticles, amorphous silicon monoxide, and Si-Li or Si-Cu alloy compounds, and it exhibits improved electrochemical properties. In particular, this composite achieved a better capacity retention, higher coulombic efficiency (over 100%), and longer cycling performance than Si alone, indicating considerable optimization of the electrical and ionic conductivity in the composite. The developed method allowed for control of the Li content to compensate for the lack of Li ions in the composite, and the cycling performance was optimized using the Cu alloy, oxide, and Li compounds within the composite.
