Inferior cycling stability, poor safety, and gas generation are long lasting problems of Ni-rich Li Ni0.80 Co0.10 Mn0.10 O2(NCM811) cathode material. Although much effort has been made, mechanisms for the above proble...Inferior cycling stability, poor safety, and gas generation are long lasting problems of Ni-rich Li Ni0.80 Co0.10 Mn0.10 O2(NCM811) cathode material. Although much effort has been made, mechanisms for the above problems are poorly understood. Studying the cycling and float-charging characteristics of Li/NCM811 cells in high voltage conditions(4.5 V and 4.7 V, respectively), in this work we find that nearly all known problems with NCM811 material can be attributed to the oxidation of lattice oxygen occurring in the capacity region corresponding to H2 → H3 phase transition. While contributing to overall capacity,the oxidation of lattice oxygen results in a loss of oxygen through oxygen evolution and relative reactions between active oxygen evolution intermediates and electrolyte solvents. It is the loss of oxygen that results in irreversible layered-spinel-rocksalt phase transition, secondary particle cracking, and performance degradation. The conclusions of this work suggest that the priority for further research on NCM811 material should give to the suppression of oxygen evolution, followed by the use of the anti-oxygen electrolyte being chemically stable against the active oxygen evolution intermediates.展开更多
O3-type layered oxide cathodes have been widely investigated due to their high reversible capacities and sufficient Na+reservoirs.However,such materials usually suffer from complex multistep phase transitions along wi...O3-type layered oxide cathodes have been widely investigated due to their high reversible capacities and sufficient Na+reservoirs.However,such materials usually suffer from complex multistep phase transitions along with drastic volume changes,leading to the unsatisfied cycle performance.Herein,we report a Mg/Ti co-doped O3-type NaNi_(0.5)Mn_(0.5)O_(2),which can effectively suppress the complex multistep phase transition and realize a solid-solution reaction within a wide voltage range.It is confirmed that,the Mg/Ti co-doping is beneficial to enhance the structural stability and integrity by absorbing micro-strain and distortions.Thus,the as obtained sample delivers an outstanding cyclic performance(82.3%after 200 cycles at 1 C)in the voltage range of 2.0-4.0 V,and a high discharge capacity of 86.6 mAh/g after 100 cycles within the wide voltage range(2.0-4.5 V),which outperform the existing literatures.This co-doping strategy offers new insights into high performance O3-type cathode for sodium ion batteries.展开更多
Photonic spin Hall effect(PSHE), as a novel physical effect in light–matter interaction, provides an effective metrological method for characterizing the tiny variation in refractive index(RI). In this work, we propo...Photonic spin Hall effect(PSHE), as a novel physical effect in light–matter interaction, provides an effective metrological method for characterizing the tiny variation in refractive index(RI). In this work, we propose a multi-functional PSHE sensor based on VO_(2), a material that can reveal the phase transition behavior. By applying thermal control, the mutual transformation into different phase states of VO_(2) can be realized, which contributes to the flexible switching between multiple RI sensing tasks. When VO_(2) is insulating, the ultrasensitive detection of glucose concentrations in human blood is achieved. When VO_(2) is in a mixed phase, the structure can be designed to distinguish between the normal cells and cancer cells through no-label and real-time monitoring. When VO_(2) is metallic, the proposed PSHE sensor can act as an RI indicator for gas analytes. Compared with other multi-functional sensing devices with the complex structures, our design consists of only one analyte and two VO_(2) layers, which is very simple and elegant. Therefore, the proposed VO_(2)-based PSHE sensor has outstanding advantages such as small size, high sensitivity, no-label, and real-time detection, providing a new approach for investigating tunable multi-functional sensors.展开更多
In this work,(1−x)(0.92NaNbO_(3)-0.08BaTiO_(3))-xCa_(0.7)La_(0.2)TiO_(3)(NNBT-xCLT)ceramics were successfully designed and prepared by the solid-state reaction method.Investigations on the structure,dielectric,a...In this work,(1−x)(0.92NaNbO_(3)-0.08BaTiO_(3))-xCa_(0.7)La_(0.2)TiO_(3)(NNBT-xCLT)ceramics were successfully designed and prepared by the solid-state reaction method.Investigations on the structure,dielectric,and energy storage properties were performed.The NNBT-0.25CLT ceramic with orthorhombic phase at room temperature was found to exhibit extremely small grain size and compacted microstructure.A large Wrec of 3.1 J/cm^(3) and a highηof 91.5%under the electric field of 360 kV/cm were achieved simultaneously in the sample.In addition,the energy storage performance of the sample exhibits thermal stability over the temperature range of 25-140°C and the frequency range of 5-500 Hz.The charge and discharge tests reveal that the ceramic shows a large current density CD of 965 A/cm2 and power density PD of 154 MW/cm^(3).This work demonstrates that the NNBT-0.25CLT ceramic is a prospective energy storage material for potential application in the field of pulsed power devices.展开更多
Solar-blind imaging has attracted considerable interest in both military and civilian applications,spurring the development of high-performance deep-ultraviolet photodetector arrays(PDAs) with wide-bandgap semiconduct...Solar-blind imaging has attracted considerable interest in both military and civilian applications,spurring the development of high-performance deep-ultraviolet photodetector arrays(PDAs) with wide-bandgap semiconductor materials.Herein,we present a novel method to enhance the performance of solar-blind PDAs(SBPDs) using β-Ga_(2)O_(3) films obtained by the phase transition of heterogeneous epitaxial sub-stable ε-Ga_(2)O_(3),achieved through high-temperature rapid annealing.Metal-semiconductor-metaltype SBPDs based on phase-transformed β-Ga_(2)O_(3) films exhibited superior performance,including an ultrahigh responsivity of 459.38 A/W,detectivity of 10^(14)–10^(15) Jones,external quantum efficiency of 10^(4)%–10^(5)%,rejection ratio(R_(254)/R_(365)) of 10^(5)–10^(6),photo-to-dark current ratio of 10^(4)–10^(6),fast response speed of 1.01 s/0.06 s,and favorable stability.Notably,the ultrahigh responsivity of β-Ga_(2)O_(3)-film-based devices was approximately 222-fold higher than that of ε-Ga_(2)O_(3) film-based devices.The assembled 4×5 β-Ga_(2)O_(3) film-based PDAs exhibited favorable uniformity,repeatability,and high spatial resolution for solarblind imaging.Our study offers a promising approach for the development of high-performance β-Ga_(2)O_(3)-based PDAs for solarblind ultraviolet imaging with potential applications in both military and civilian fields.展开更多
In this paper, a novel heat sink which coupling natural convection and phase transition was designed to meet the cooling requirements of distribution level static synchronous compensator(DSTATCOM). The two inclined ev...In this paper, a novel heat sink which coupling natural convection and phase transition was designed to meet the cooling requirements of distribution level static synchronous compensator(DSTATCOM). The two inclined evaporation substrates can meet the requirements for the parallel operation of DSTATCOM and the working medium R245 fa was driven by gravity and buoyancy in the heat sink. The influence of filling ratio and heating power on the thermal performance of the heat sink was investigated experimentally and theoretically. The experimental results showed that the filling ratio and heating power had a significant influence on the thermal performance of the heat sink. At the ambient temperature of 25℃, the heat sink could start up successfully at different heating power and filling ratio. Meanwhile, the heat sink achieved good heat dissipation performance as the maximum temperature of two evaporation substrates were 60.14℃ and 67.85℃ while the heating power was 3000 Wand the filling ratio was 80%. The heat transfer resistance between two evaporation substrates and condensation substrates were6.6×10^-3℃/W and 1.2×10^-2℃/W at the same working condition. Additionally, the experimental results showed a good agreement with the calculated results.展开更多
文摘Inferior cycling stability, poor safety, and gas generation are long lasting problems of Ni-rich Li Ni0.80 Co0.10 Mn0.10 O2(NCM811) cathode material. Although much effort has been made, mechanisms for the above problems are poorly understood. Studying the cycling and float-charging characteristics of Li/NCM811 cells in high voltage conditions(4.5 V and 4.7 V, respectively), in this work we find that nearly all known problems with NCM811 material can be attributed to the oxidation of lattice oxygen occurring in the capacity region corresponding to H2 → H3 phase transition. While contributing to overall capacity,the oxidation of lattice oxygen results in a loss of oxygen through oxygen evolution and relative reactions between active oxygen evolution intermediates and electrolyte solvents. It is the loss of oxygen that results in irreversible layered-spinel-rocksalt phase transition, secondary particle cracking, and performance degradation. The conclusions of this work suggest that the priority for further research on NCM811 material should give to the suppression of oxygen evolution, followed by the use of the anti-oxygen electrolyte being chemically stable against the active oxygen evolution intermediates.
基金supported by the National Natural Science Foundation of China(Nos.22179077,51774251,21908142)Shanghai Science and Technology Commission’s“2020 Science and Technology In-novation Action Plan”(No.20511104003)Natural Science Foundation in Shanghai(No.21ZR1424200)。
文摘O3-type layered oxide cathodes have been widely investigated due to their high reversible capacities and sufficient Na+reservoirs.However,such materials usually suffer from complex multistep phase transitions along with drastic volume changes,leading to the unsatisfied cycle performance.Herein,we report a Mg/Ti co-doped O3-type NaNi_(0.5)Mn_(0.5)O_(2),which can effectively suppress the complex multistep phase transition and realize a solid-solution reaction within a wide voltage range.It is confirmed that,the Mg/Ti co-doping is beneficial to enhance the structural stability and integrity by absorbing micro-strain and distortions.Thus,the as obtained sample delivers an outstanding cyclic performance(82.3%after 200 cycles at 1 C)in the voltage range of 2.0-4.0 V,and a high discharge capacity of 86.6 mAh/g after 100 cycles within the wide voltage range(2.0-4.5 V),which outperform the existing literatures.This co-doping strategy offers new insights into high performance O3-type cathode for sodium ion batteries.
基金Project supported by the National Natural Science Foundation of China(Grant No.NSFC 12175107)the Natural Science Foundation of Nanjing Vocational University of Industry Technology,China(Grant No.YK22-02-08)+3 种基金the Qing Lan Project of Jiangsu Province,Chinathe Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(Grant No.KYCX23_0964)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20230347)the Fund from the Research Center of Industrial Perception and Intelligent Manufacturing Equipment Engineering of Jiangsu Province,China(Grant No.ZK21-05-09)。
文摘Photonic spin Hall effect(PSHE), as a novel physical effect in light–matter interaction, provides an effective metrological method for characterizing the tiny variation in refractive index(RI). In this work, we propose a multi-functional PSHE sensor based on VO_(2), a material that can reveal the phase transition behavior. By applying thermal control, the mutual transformation into different phase states of VO_(2) can be realized, which contributes to the flexible switching between multiple RI sensing tasks. When VO_(2) is insulating, the ultrasensitive detection of glucose concentrations in human blood is achieved. When VO_(2) is in a mixed phase, the structure can be designed to distinguish between the normal cells and cancer cells through no-label and real-time monitoring. When VO_(2) is metallic, the proposed PSHE sensor can act as an RI indicator for gas analytes. Compared with other multi-functional sensing devices with the complex structures, our design consists of only one analyte and two VO_(2) layers, which is very simple and elegant. Therefore, the proposed VO_(2)-based PSHE sensor has outstanding advantages such as small size, high sensitivity, no-label, and real-time detection, providing a new approach for investigating tunable multi-functional sensors.
基金supported by the National Natural Science Foundation of China(NSFC)Grants 12174001 and 51872001(C.Wang)NSFC Grant 12104001Anhui Provincial Natural Science Foundation of Grant 2008085QE205(F.Li).
文摘In this work,(1−x)(0.92NaNbO_(3)-0.08BaTiO_(3))-xCa_(0.7)La_(0.2)TiO_(3)(NNBT-xCLT)ceramics were successfully designed and prepared by the solid-state reaction method.Investigations on the structure,dielectric,and energy storage properties were performed.The NNBT-0.25CLT ceramic with orthorhombic phase at room temperature was found to exhibit extremely small grain size and compacted microstructure.A large Wrec of 3.1 J/cm^(3) and a highηof 91.5%under the electric field of 360 kV/cm were achieved simultaneously in the sample.In addition,the energy storage performance of the sample exhibits thermal stability over the temperature range of 25-140°C and the frequency range of 5-500 Hz.The charge and discharge tests reveal that the ceramic shows a large current density CD of 965 A/cm2 and power density PD of 154 MW/cm^(3).This work demonstrates that the NNBT-0.25CLT ceramic is a prospective energy storage material for potential application in the field of pulsed power devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.11904041 and 12104077)the Natural Science Foundation of Chongqing(Grant Nos.cstc2020jcyj-msxmX0557,cstc2019jcyj-msxmX0237,cstc2020jcyj-msxmX0533,and CSTB2022BSXM-JCX0090)+1 种基金the Science and Technology Research Project of Chongqing Education Committee(Grant Nos.KJQN202100540,KJQN202000511,and KJQN202100501)the College Students Innovation and Entrepreneurship Training Program of Chongqing City(Grant No.S202210637052)。
文摘Solar-blind imaging has attracted considerable interest in both military and civilian applications,spurring the development of high-performance deep-ultraviolet photodetector arrays(PDAs) with wide-bandgap semiconductor materials.Herein,we present a novel method to enhance the performance of solar-blind PDAs(SBPDs) using β-Ga_(2)O_(3) films obtained by the phase transition of heterogeneous epitaxial sub-stable ε-Ga_(2)O_(3),achieved through high-temperature rapid annealing.Metal-semiconductor-metaltype SBPDs based on phase-transformed β-Ga_(2)O_(3) films exhibited superior performance,including an ultrahigh responsivity of 459.38 A/W,detectivity of 10^(14)–10^(15) Jones,external quantum efficiency of 10^(4)%–10^(5)%,rejection ratio(R_(254)/R_(365)) of 10^(5)–10^(6),photo-to-dark current ratio of 10^(4)–10^(6),fast response speed of 1.01 s/0.06 s,and favorable stability.Notably,the ultrahigh responsivity of β-Ga_(2)O_(3)-film-based devices was approximately 222-fold higher than that of ε-Ga_(2)O_(3) film-based devices.The assembled 4×5 β-Ga_(2)O_(3) film-based PDAs exhibited favorable uniformity,repeatability,and high spatial resolution for solarblind imaging.Our study offers a promising approach for the development of high-performance β-Ga_(2)O_(3)-based PDAs for solarblind ultraviolet imaging with potential applications in both military and civilian fields.
基金supported by the National Natural Science Foundation of China (Grant No. 51225602)。
文摘In this paper, a novel heat sink which coupling natural convection and phase transition was designed to meet the cooling requirements of distribution level static synchronous compensator(DSTATCOM). The two inclined evaporation substrates can meet the requirements for the parallel operation of DSTATCOM and the working medium R245 fa was driven by gravity and buoyancy in the heat sink. The influence of filling ratio and heating power on the thermal performance of the heat sink was investigated experimentally and theoretically. The experimental results showed that the filling ratio and heating power had a significant influence on the thermal performance of the heat sink. At the ambient temperature of 25℃, the heat sink could start up successfully at different heating power and filling ratio. Meanwhile, the heat sink achieved good heat dissipation performance as the maximum temperature of two evaporation substrates were 60.14℃ and 67.85℃ while the heating power was 3000 Wand the filling ratio was 80%. The heat transfer resistance between two evaporation substrates and condensation substrates were6.6×10^-3℃/W and 1.2×10^-2℃/W at the same working condition. Additionally, the experimental results showed a good agreement with the calculated results.
