Lithium metal batteries represent promising candidates for high-energy-density batteries, however, many challenges must still be overcome,e.g., interface instability and dendrite growth. In this work, nano silica aero...Lithium metal batteries represent promising candidates for high-energy-density batteries, however, many challenges must still be overcome,e.g., interface instability and dendrite growth. In this work, nano silica aerogel was employed to generate a hybrid film with high lithium ion conductivity(0.6 mS cm^(-1)at room temperature) via an in situ crosslinking reaction. TOF-SIMS profile analysis has revealed conversion mechanism of hybrid film to Li–Si alloy/Li F biphasic interface layer, suggesting that the Li–Si alloy and Li F-rich interface layer promoted rapid Li+transport and shielded the Li anodes from corrosive reactions with electrolyte-derived products. When coupled with nickel-cobalt-manganese-based cathodes, the batteries achieve outstanding capacity retention over 1000 cycles at 1 C. Additionally the developed film coated on Li enabled high coulombic efficiency(99.5%) after long-term cycling when coupled with S cathodes. Overall, the results presented herein confirm an effective strategy for the development of high-energy batteries.展开更多
2D position sensitive, single-sided Si stripixel detector was selected as the one of the two main components of the Si vertex tracker (Si SVX) in the upgraded PHENIX detector at RHIC (relativistic heavy ion collider) ...2D position sensitive, single-sided Si stripixel detector was selected as the one of the two main components of the Si vertex tracker (Si SVX) in the upgraded PHENIX detector at RHIC (relativistic heavy ion collider) in Brookhaven National Laboratory (BNL). This is the first large scale application of the novel Si stripixel detector in a real large experiment after many years of research and development at BNL. The first and second prototype fabrication runs of the SVX stripixel detectors were carried out successfully in BNL’s Si detector development and processing Lab. The processing of these stripixel detectors is similar to that for the standard single-sided strip detectors: one-sided processing, single implant for the pixel (strip) electrodes, etc. The only additional processing step is the double metal process, a technology that is simple and well matured by many Si detector processing industries and labs, including BNL. The laser and beam tests on those prototype detectors show the 2D position sensitivity and good position resolution in both X and U coordinates (about 25 μm for 80 μm pitch). For the mass production of 400 sensors needed for the Si SVX, the processing technology has been successfully transferred to the industrial: Hamamatsu Photonics (HPK). HPK has produced a pre-production run of stripixel sensors with the full PHENIX SVX specification on 150 mm diameter wafers. The laser tests on these pre-production wafers show good signal to noise ratio (about 20∶1).展开更多
The crosstalk caused by oblique incident ray on a PIN detector array is analyzed. An integral expression of crosstalk factor in relation to incident angle and structure parameters is deduced and the correctness of the...The crosstalk caused by oblique incident ray on a PIN detector array is analyzed. An integral expression of crosstalk factor in relation to incident angle and structure parameters is deduced and the correctness of the deduction is tested and verified.展开更多
采用杂化密度泛函B3LYP理论,对Si_5及Li原子修饰的Si_5团簇的几何结构和电子性质及储氢性能进行了研究。结果表明:Si_5团簇最低能量构型为笼型结构,纯笼型Si_5团簇不能有效地吸附氢分子;Li原子的修饰可以显著改善其储氢能力,在两个Li原...采用杂化密度泛函B3LYP理论,对Si_5及Li原子修饰的Si_5团簇的几何结构和电子性质及储氢性能进行了研究。结果表明:Si_5团簇最低能量构型为笼型结构,纯笼型Si_5团簇不能有效地吸附氢分子;Li原子的修饰可以显著改善其储氢能力,在两个Li原子端位修饰Si_5笼型团簇体系中,其氢分子的平均吸附能为7.259~11.330 k J/mol,每个Li原子周围可以有效吸附5个氢分子,储氢质量分数达11.554%。因此,Li修饰Si_5笼型团簇体系有望成为理想的储氢材料。展开更多
基金the support from National Natural Science Foundation of China (22179006)International Science & Technology Cooperation Program of China under Contract No.2019YFE0100200+3 种基金National Natural Science Foundation of China (52072036)NSAF (No.U1930113)Guangdong Key Laboratory of Battery Safety,China (No.2019B121203008)China Postdoctoral Science Foundation (No.2021TQ0034)。
文摘Lithium metal batteries represent promising candidates for high-energy-density batteries, however, many challenges must still be overcome,e.g., interface instability and dendrite growth. In this work, nano silica aerogel was employed to generate a hybrid film with high lithium ion conductivity(0.6 mS cm^(-1)at room temperature) via an in situ crosslinking reaction. TOF-SIMS profile analysis has revealed conversion mechanism of hybrid film to Li–Si alloy/Li F biphasic interface layer, suggesting that the Li–Si alloy and Li F-rich interface layer promoted rapid Li+transport and shielded the Li anodes from corrosive reactions with electrolyte-derived products. When coupled with nickel-cobalt-manganese-based cathodes, the batteries achieve outstanding capacity retention over 1000 cycles at 1 C. Additionally the developed film coated on Li enabled high coulombic efficiency(99.5%) after long-term cycling when coupled with S cathodes. Overall, the results presented herein confirm an effective strategy for the development of high-energy batteries.
基金Project(DE-Ac02-98CH10886) supported in part by the US Department of Energy
文摘2D position sensitive, single-sided Si stripixel detector was selected as the one of the two main components of the Si vertex tracker (Si SVX) in the upgraded PHENIX detector at RHIC (relativistic heavy ion collider) in Brookhaven National Laboratory (BNL). This is the first large scale application of the novel Si stripixel detector in a real large experiment after many years of research and development at BNL. The first and second prototype fabrication runs of the SVX stripixel detectors were carried out successfully in BNL’s Si detector development and processing Lab. The processing of these stripixel detectors is similar to that for the standard single-sided strip detectors: one-sided processing, single implant for the pixel (strip) electrodes, etc. The only additional processing step is the double metal process, a technology that is simple and well matured by many Si detector processing industries and labs, including BNL. The laser and beam tests on those prototype detectors show the 2D position sensitivity and good position resolution in both X and U coordinates (about 25 μm for 80 μm pitch). For the mass production of 400 sensors needed for the Si SVX, the processing technology has been successfully transferred to the industrial: Hamamatsu Photonics (HPK). HPK has produced a pre-production run of stripixel sensors with the full PHENIX SVX specification on 150 mm diameter wafers. The laser tests on these pre-production wafers show good signal to noise ratio (about 20∶1).
文摘The crosstalk caused by oblique incident ray on a PIN detector array is analyzed. An integral expression of crosstalk factor in relation to incident angle and structure parameters is deduced and the correctness of the deduction is tested and verified.
文摘采用杂化密度泛函B3LYP理论,对Si_5及Li原子修饰的Si_5团簇的几何结构和电子性质及储氢性能进行了研究。结果表明:Si_5团簇最低能量构型为笼型结构,纯笼型Si_5团簇不能有效地吸附氢分子;Li原子的修饰可以显著改善其储氢能力,在两个Li原子端位修饰Si_5笼型团簇体系中,其氢分子的平均吸附能为7.259~11.330 k J/mol,每个Li原子周围可以有效吸附5个氢分子,储氢质量分数达11.554%。因此,Li修饰Si_5笼型团簇体系有望成为理想的储氢材料。
