The Experts below are selected from a list of 8364 Experts worldwide ranked by ideXlab platform
Henning Markotter - One of the best experts on this subject based on the ideXlab platform.
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editors choice 4d neutron and x ray tomography studies of high energy density Primary Batteries part ii multi modal microscopy of lisocl2 cells
Journal of The Electrochemical Society, 2020Co-Authors: R Ziesche, James B Robinson, Henning Markotter, Robert Bradbury, Alessandro Tengattini, Nicolas Lenoir, Lukas HelfenAbstract:The ability to track electrode degradation, both spatially and temporally, is fundamental to understand performance loss during operation of lithium Batteries. X-ray computed tomography can be used to follow structural and morphological changes in electrodes; however, the direct detection of electrochemical processes related to metallic lithium is difficult due to the low sensitivity to the element. In this work, 4-dimensional neutron computed tomography, which shows high contrast for lithium, is used to directly quantify the lithium diffusion process in spirally wound Li/SOCl2 Primary cells. The neutron dataset enables the quantification of the lithium transport from the anode and the accumulation inside the SOCl2 cathode to be locally resolved. Complementarity between the collected neutron and X-ray computed tomographies is shown and by applying both methods in concert we have observed lithium diffusion blocking by the LiCl protection layer and identified all cell components which are difficult to distinguish using one of the methods alone.
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editors choice 4d neutron and x ray tomography studies of high energy density Primary Batteries part i dynamic studies of lisocl2 during discharge
Journal of The Electrochemical Society, 2020Co-Authors: R Ziesche, James B Robinson, Henning Markotter, Matt D R Kok, W Kockelmann, Nikolay Kardjilov, Ingo Manke, Dan J L BrettAbstract:The understanding of dynamic processes in Li-metal Batteries is an important consideration to enable the full capacity of cells to be utilised. These processes, however, are generally not directly observable using X-ray techniques due to the low attenuation of Li; and are challenging to visualise using neutron imaging due to the low temporal resolution of the technique. In this work, complementary X-ray and neutron imaging are combined to track the dynamics of Li within a Primary Li/SOCl2 cell. The temporal challenges posed by neutron imaging are overcome using the golden ratio imaging method which enables the identification of Li diffusion in operando. This combination of techniques has enabled an improved understanding of the processes which limit rate performance in Li/SOCl2 cells and may be applied beyond this chemistry to other Li-metal cells.
Yusuke Yamauchi - One of the best experts on this subject based on the ideXlab platform.
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ultralong storage life of li mno2 Primary Batteries using mno2 cfx n with c f semi ionic bond as cathode materials
Electrochimica Acta, 2019Co-Authors: Yali Chang, Jongbeom Na, Ashok Kumar Nanjundan, Yusuke Yamauchi, Andreas Bund, Shengping Wang, Min WangAbstract:Abstract The theoretical self-discharge rate of Li/MnO2 Primary Batteries is less than 1% per year, but the actual self-discharge rate is ∼8% per year, and the shelf life of the coin Batteries (such as CR2016) is only 5 years. In this paper, MnO2 mixed some (CFx)n as cathode material in Li/MnO2 Primary Batteries, not only can effectively reduce self-discharge rate, but also improve capacity density and heighten discharge plateau voltageafter storage. After storage at 25 °C for 60 days, the specific charge capacity of MnO2 decreases from 293 mAh g−1 to 283 mAh g−1, while MnO2-(CFx)n increases from 312 mAh g−1 to 326 mAh g−1. After storage for 30 days at 45 °C, the self-discharge rates of MnO2 and MnO2-(CFx)n are 9.21% and 1.92% (0.5 mA cm−2), respectively. During storage and the initial stage of discharge, F in MnO2-(CFx)n can act on Mn–O bond and some C–F semi-ionic bonds form when Li+ insert into (CFx)n layers, these change the unit cell parameters of MnO2 and the utilization of MnO2 increases.
Hongjun Yue - One of the best experts on this subject based on the ideXlab platform.
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high power density high energy density fluorinated graphene for Primary lithium Batteries
Frontiers in Chemistry, 2018Co-Authors: Guiming Zhong, Huixin Chen, Xingkang Huang, Hongjun YueAbstract:Li/CFx is one of the highest-energy-density Primary Batteries; however, poor rate capability hinders its practical applications in high-power devices. Here we report a preparation of fluorinated graphene (GFx) with superior performance through a direct gas fluorination method. We find that the so-called "semi-ionic" C-F bond content in all C-F bonds presents a more critical impact on rate performance of the GFx in comparison with sp2 C content in the GFx, morphology, structure, and specific surface area of the materials. The rate capability remains excellent before the semi-ionic C-F bond proportion in the GFx decreases. Thus, by optimizing semi-ionic C-F content in our GFx, we obtain the optimal x of 0.8, with which the GF0.8 exhibits a very high energy density of 1,073 Wh kg-1 and an excellent power density of 21,460 W kg-1 at a high current density of 10 A g-1. More importantly, our approach opens a new avenue to obtain fluorinated carbon with high energy densities without compromising high power densities.
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synthesis and characterization of fluorinated carbon nanotubes for lithium Primary Batteries with high power density
Nanotechnology, 2013Co-Authors: Hongjun Yue, Wei Zhang, Haodong Liu, Zigeng Liu, Guiming Zhong, Yong YangAbstract:The synthesis and characterization of fluorinated carbon nanotubes have been carried out under an inert gas containing fluorine. All of the samples have been characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), solid-state nuclear magnetic resonance (13C and 19F ss-NMR) and transmission electron microscopy (TEM) techniques. The comparison of the effects of various experimental parameters on the structure of fluorinated materials allows the disclosure of the fluorination mechanism. It is shown that fluorine was intercalated into the outer part of the carbon nanotubes initially where graphene layers were coaxial within a distance of 0.60 nm. In contrast, the inner part of the carbon nanotubes was not intercalated. The electrochemical performance such as discharge capacity as a cathode for a Primary lithium battery has also been investigated. The samples with a F/C ratio of 0.75 exhibited the best performance, namely high energy and power densities. The highest specific energy density and specific power density were 1147 Wh kg−1 and 8998 W kg−1, respectively, at a current density of 4 A g−1.
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enhanced electrochemical performance of fluorinated carbon nanotube as cathode for li o2 Primary Batteries
Electrochimica Acta, 2013Co-Authors: Yanyan Tian, Hongjun Yue, Zhengliang Gong, Yong YangAbstract:National Natural Science Foundation of China [21021002, 21233004]; National Basic Research Program of China (973 Program) from the Ministry of Science and Technology, China [2011CB935903]
Yong Yang - One of the best experts on this subject based on the ideXlab platform.
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insights into the lithiation mechanism of cfx by a joint high resolution 19f nmr in situ tem and 7li nmr approach
Journal of Materials Chemistry, 2019Co-Authors: Guiming Zhong, Huixin Chen, Yong Cheng, Lingyi Meng, Guorui Zheng, Yuxuan Xiang, Qi Li, Qiaobao Zhang, Canzhong Lu, Yong YangAbstract:Li/CFx cells possess the highest energy density among all lithium Primary Batteries. Here, the electrochemical lithiation process is elucidated through high-resolution 19F NMR, in situ7Li NMR and TEM methods. Fluorinated carbon CFL (L is around 0.06 or less) is identified for the first time to be generated in the discharge process of CFx (x ≥ 0.5) besides LiF and carbon. Moreover, the morphological evolution of the formed LiF, which affects the impedance of the battery during discharge, is illustrated as crystal nuclei of LiF, with a size of around 10 nm, which keep forming and growing into crystal grains of LiF, with a size of around 200 nm, until the surface of the CFx particles is saturated by LiF and then both crystal nuclei and grains enlarged promptly towards the end of lithiation. This work reveals the electrochemical reaction mechanism of CFx and provides crucial guidance to enhance the performance of the materials.
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synthesis and characterization of fluorinated carbon nanotubes for lithium Primary Batteries with high power density
Nanotechnology, 2013Co-Authors: Hongjun Yue, Wei Zhang, Haodong Liu, Zigeng Liu, Guiming Zhong, Yong YangAbstract:The synthesis and characterization of fluorinated carbon nanotubes have been carried out under an inert gas containing fluorine. All of the samples have been characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), solid-state nuclear magnetic resonance (13C and 19F ss-NMR) and transmission electron microscopy (TEM) techniques. The comparison of the effects of various experimental parameters on the structure of fluorinated materials allows the disclosure of the fluorination mechanism. It is shown that fluorine was intercalated into the outer part of the carbon nanotubes initially where graphene layers were coaxial within a distance of 0.60 nm. In contrast, the inner part of the carbon nanotubes was not intercalated. The electrochemical performance such as discharge capacity as a cathode for a Primary lithium battery has also been investigated. The samples with a F/C ratio of 0.75 exhibited the best performance, namely high energy and power densities. The highest specific energy density and specific power density were 1147 Wh kg−1 and 8998 W kg−1, respectively, at a current density of 4 A g−1.
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enhanced electrochemical performance of fluorinated carbon nanotube as cathode for li o2 Primary Batteries
Electrochimica Acta, 2013Co-Authors: Yanyan Tian, Hongjun Yue, Zhengliang Gong, Yong YangAbstract:National Natural Science Foundation of China [21021002, 21233004]; National Basic Research Program of China (973 Program) from the Ministry of Science and Technology, China [2011CB935903]
P. E. Bradley - One of the best experts on this subject based on the ideXlab platform.
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off state conductance measurements of the nist lockheed martin miniature pulse tube flight cryocooler laboratory vs space
Advances in cryogenic engineering, 2002Co-Authors: D. R. Ladner, R. Radebaugh, P. E. BradleyAbstract:A two-stage miniature pulse tube (PT) cryocooler, designed for a Space Shuttle flight demonstration, was built and tested at Lockheed Martin Astronautics (LMA) and at the NIST Boulder Lab. The Miniature PT Flight Cryocooler (MPTFC) was designed to provide 0.15 W of cooling at 80 K with heat rejection at 275 K. It was developed as the smallest cryocooler of its kind for the purpose of demonstrating launch survivability and thermal performance in a zero-g environment. The flight version was fabricated as a Getaway Special (GAS) Payload. Although on-orbit cooling performance was not demonstrated because of failed Primary Batteries, the first off-state PT thermal conductance measurements in zero-g were conducted successfully using the secondary battery system. The data acquisition system and all flight diagnostic sensors performed nominally to provide 15 hours of zero-g warm-up data. The results of the cold head thermal conductance measurements both in zero-g aboard STS-90 and in the laboratory environment are compared to a thermal model for the two-stage PT, detailed in a separate presentation.
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design and test of the nist lockheed martin miniature pulse tube flight cryocooler
2002Co-Authors: P. E. Bradley, R. Radebaugh, J. H. Xiao, D. R. LadnerAbstract:A two-stage miniature pulse tube (PT) cryocooler, designed for a Space Shuttle flight demonstration, was built and tested at Lockheed Martin Astronautics (LMA) at Denver, CO and the NIST Boulder Laboratory. The Miniature PT Flight Cryocooler (MPTFC) was designed to provide 0.15 W of cooling at 80 K with heat rejection at 275 K. It was developed as the smallest cryocooler of its kind for the purpose of demonstrating launch survivability and thermal performance in a zero-g environment. A prototype laboratory version was first built and tested to provide information on component sizing and flow rates for comparison to numerical models. The flight version was then fabricated as a Getaway Special (GAS) Payload. Cost containment and manned flight safety constraints limited the extent of the MPTFC development to achieve performance optimization. Nonetheless, it reached 87 K driven by a commercially available tactical compressor with a swept volume of 0.75 cc. The on-orbit cooling performance was not demonstrated because of low battery voltage resulting from failed Primary Batteries. The first off-state PT thermal conductance measurements were successful, however, and the MPTFC also demonstrated the robustness of PT cryocoolers by surviving pro-launch vibration testing, shipping, and the launch and landing of STS-90 with no measurable performance degradation.