The Experts below are selected from a list of 56937 Experts worldwide ranked by ideXlab platform
Andreas Schnepf - One of the best experts on this subject based on the ideXlab platform.
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ge14 ge sime3 3 5li3 thf 6 the largest metalloid cluster compound of Germanium on the way to fullerene like compounds
Chemical Communications, 2008Co-Authors: Christian Schenk, Andreas SchnepfAbstract:The reaction of GeBr with LiGe(SiMe3)3 yields the largest metalloid cluster compound of Germanium Ge14[Ge(SiMe3)3]5Li3(THF)6, in which 14 Germanium atoms are arranged as a hollow sphere in the cluster core, showing that in the case of Germanium also fullerene-like compounds might be present in the borderland between the molecular and solid states.
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metalloid cluster compounds of Germanium a novel class of Germanium cluster compounds of formulae genrm n m
Coordination Chemistry Reviews, 2006Co-Authors: Andreas SchnepfAbstract:Abstract Metalloid cluster compounds of Germanium of the general formulae Ge n R m with n > m , where in addition to ligand bound Germanium atoms, “naked” Germanium atoms are also present, represent a novel class of cluster compounds in Germanium chemistry. Due to the fact that the “naked” Germanium atoms inside these clusters can be assigned an oxidation state of 0, the average oxidation state of the Germanium atoms inside such metalloid cluster compounds is between 0 and 1. Thus these cluster compounds can be seen as on the way to elemental Germanium and therefore interesting properties are expected for these compounds which might give impact to nanotechnology. During the last 3 years, different synthetic strategies have been introduced for the synthesis of such novel cluster compounds featuring unexpected structural and bonding properties. In this article, an account is given to the first developments in this novel field in Germanium chemistry in which special attention is given to structural features and bonding properties.
Seongbeom Kim - One of the best experts on this subject based on the ideXlab platform.
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production of Germanium nanoparticles via laser pyrolysis for anode materials of lithium ion batteries and sodium ion batteries
Nanotechnology, 2019Co-Authors: Taehee Kim, Hyunkon Song, Seongbeom KimAbstract:Germanium nanoparticles were synthesized and subjected to study as anode materials for lithium ion batteries and sodium ion batteries. Laser pyrolysis of GeH4 was used to produce Germanium nanoparticles and the average diameter of these nanoparticles was easily controlled by regulating sensitizer gas flow rates during the process. 60 and 10 nm diameter nanoparticles were synthesized and micron-size powder was purchased and these three pure Germanium powder samples were tested as the anode materials of lithium ion batteries and sodium ion batteries in terms of cycle retention, long term cycles and the kinetics of reactions. Experimental results showed that the smallest powder sample which is synthesized, average 10 nm, exhibited excellent performances in both kinds of batteries. According to the results, the characteristics of batteries improved as the size of Germanium powder decreased consistently. Pure Germanium was thoroughly investigated as an anode of metal-ion batteries with regard to its powder size. The experimental data and synthesis approach of Germanium nanoparticles suggested in this research would be a good example for the utilization of elemental Germanium in high performance batteries.
Soojin Park - One of the best experts on this subject based on the ideXlab platform.
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cost effective scalable synthesis of mesoporous Germanium particles via a redox transmetalation reaction for high performance energy storage devices
ACS Nano, 2015Co-Authors: Sinho Choi, Ji Eun Kim, Namsoon Choi, Min Gyu Kim, Soojin ParkAbstract:Nanostructured Germanium is a promising material for high-performance energy storage devices. However, synthesizing it in a cost-effective and simple manner on a large scale remains a significant challenge. Herein, we report a redox-transmetalation reaction-based route for the large-scale synthesis of mesoporous Germanium particles from Germanium oxide at temperatures of 420-600 °C. We could confirm that a unique redox-transmetalation reaction occurs between Zn(0) and Ge(4+) at approximately 420 °C using temperature-dependent in situ X-ray absorption fine structure analysis. This reaction has several advantages, which include (i) the successful synthesis of Germanium particles at a low temperature (∼450 °C), (ii) the accommodation of large volume changes, owing to the mesoporous structure of the Germanium particles, and (iii) the ability to synthesize the particles in a cost-effective and scalable manner, as inexpensive metal oxides are used as the starting materials. The optimized mesoporous Germanium anode exhibits a reversible capacity of ∼1400 mA h g(-1) after 300 cycles at a rate of 0.5 C (corresponding to the capacity retention of 99.5%), as well as stable cycling in a full cell containing a LiCoO2 cathode with a high energy density (charge capacity = 286.62 mA h cm(-3)).
Taehee Kim - One of the best experts on this subject based on the ideXlab platform.
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production of Germanium nanoparticles via laser pyrolysis for anode materials of lithium ion batteries and sodium ion batteries
Nanotechnology, 2019Co-Authors: Taehee Kim, Hyunkon Song, Seongbeom KimAbstract:Germanium nanoparticles were synthesized and subjected to study as anode materials for lithium ion batteries and sodium ion batteries. Laser pyrolysis of GeH4 was used to produce Germanium nanoparticles and the average diameter of these nanoparticles was easily controlled by regulating sensitizer gas flow rates during the process. 60 and 10 nm diameter nanoparticles were synthesized and micron-size powder was purchased and these three pure Germanium powder samples were tested as the anode materials of lithium ion batteries and sodium ion batteries in terms of cycle retention, long term cycles and the kinetics of reactions. Experimental results showed that the smallest powder sample which is synthesized, average 10 nm, exhibited excellent performances in both kinds of batteries. According to the results, the characteristics of batteries improved as the size of Germanium powder decreased consistently. Pure Germanium was thoroughly investigated as an anode of metal-ion batteries with regard to its powder size. The experimental data and synthesis approach of Germanium nanoparticles suggested in this research would be a good example for the utilization of elemental Germanium in high performance batteries.
Sinho Choi - One of the best experts on this subject based on the ideXlab platform.
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cost effective scalable synthesis of mesoporous Germanium particles via a redox transmetalation reaction for high performance energy storage devices
ACS Nano, 2015Co-Authors: Sinho Choi, Ji Eun Kim, Namsoon Choi, Min Gyu Kim, Soojin ParkAbstract:Nanostructured Germanium is a promising material for high-performance energy storage devices. However, synthesizing it in a cost-effective and simple manner on a large scale remains a significant challenge. Herein, we report a redox-transmetalation reaction-based route for the large-scale synthesis of mesoporous Germanium particles from Germanium oxide at temperatures of 420-600 °C. We could confirm that a unique redox-transmetalation reaction occurs between Zn(0) and Ge(4+) at approximately 420 °C using temperature-dependent in situ X-ray absorption fine structure analysis. This reaction has several advantages, which include (i) the successful synthesis of Germanium particles at a low temperature (∼450 °C), (ii) the accommodation of large volume changes, owing to the mesoporous structure of the Germanium particles, and (iii) the ability to synthesize the particles in a cost-effective and scalable manner, as inexpensive metal oxides are used as the starting materials. The optimized mesoporous Germanium anode exhibits a reversible capacity of ∼1400 mA h g(-1) after 300 cycles at a rate of 0.5 C (corresponding to the capacity retention of 99.5%), as well as stable cycling in a full cell containing a LiCoO2 cathode with a high energy density (charge capacity = 286.62 mA h cm(-3)).
