Über Alkaligraphitverbindungen

R�dorff, W.; Schulze, Egbert

doi:10.1002/zaac.19542770307

Cited by 234 publications

(72 citation statements)

References 5 publications

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“…They observed the reversible sequence C-KC 36 -KC 24 -KC 8 (Figure 2e,f), indicating that the stage 3, 2, and 1 compounds crystallized in a sequence analogous to the crystallization of the phases prepared by the two-zone vapor method, [31,32] except that the stage 4 and 5 compounds were not detected electrochemically. This discrepancy could originate from the fact that ex situ diffraction was only performed on a limited number of samples (i.e., nonoperando conditions) and it is easy to miss phases that exist in a narrow composition range.…”

Section: Graphite Anodesmentioning

confidence: 99%

“…[31,32] These compounds were prepared using non-electrochemical methods, through a two-zone vapor transport method, which applies K vapor onto graphite in a custom-made double furnace. Several compounds were isolated in these studies from stage 1 to stage 5 of potassiation, [33] with stage 1 corresponding to the most K-rich compound, KC 8 .…”

Section: Graphite Anodesmentioning

confidence: 99%

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Recent Progress and Perspective in Electrode Materials for K‐Ion Batteries

Kim

Bianchini

et al. 2017

Advanced Energy Materials

601

465

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and demand in terms of time and space. Thus, grid-level stationary energy storage systems (ESSs) play a key role in making renewable energies both effective and efficient and thereby shaping a more sustainable and environmental friendly society.Although different energy storage technologies including mechanical, electrical, chemical, and electrochemical systems have been proposed, [2,3] mechanical energy storage through pumped hydroelectricity currently dominates the market (≈95% of the installed capacity, ≈183 GW). [4] Electrochemical energy storage is also being considered as a promising option for ESSs based on its flexibility of deployment with little restriction on size and geographical location, low maintenance costs, large energy density, high round-trip efficiency, and long cycle life. [3,5,6] The market for Li-ion batteries (LIBs), originally commercialized for portable electronic devices (i.e., cell phones and laptops), is now expanding to electric vehicles (EVs) and gridlevel ESSs. However, it remains debatable whether the global Li reserves, ≈14 million tons, can meet the increasing demand for such large-scale applications. [7][8][9] The price of lithium carbonate, which is a primary precursor for LIBs, has been continuously increasing since 2000, [10] and this trend is likely to accelerate once the EV and ESS markets take off. Moreover, Li is geographically limited to specific regions: ≈86% of the Li reserves are located in Bolivia, Chile, China, Argentina, and Australia; [9] therefore, geopolitical issues may arise. A more pressing issue for Li-ion markets is the use of Co in all high-energy-density systems. With more than 50% of all mined Co destined for use in Li-ion technology, and a substantial fraction of that coming from the Democratic Republic of the Congo, Li-ion growth may be hampered by the availability of Co. [11] As a less expensive alternative to LIBs, Na-ion batteries (NIBs) have been extensively studied. [6,[12][13][14] The relatively high standard redox potential of Na/Na + leads to a lower working voltage and thereby lower energy density than Li-ion. In addition, hard carbon, which is associated with a high production cost and low material's density, must be used as an anode in NIBs, as graphite, which is the standard anode for LIBs, cannot store Na ions. [15][16][17] Recently, K-ion batteries (KIBs) have emerged as another possible energy storage system. [18][19][20] It is notable that the abundance of K resources in the Earth's crust and oceans is similar to that of Na (Figure 1a). [21,22] The cost of potassium carbonate The development of rechargeable batteries using K ions as charge carriers has recently attracted considerable attention in the search for cost-effective and large-scale energy storage systems. In light of this trend, various materials for positive and negative electrodes are proposed and evaluated for application in K-ion batteries. Here, a comprehensive review of ongoing materials research on nonaqueous K-ion batteries is offered. Information on the status of ...

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Section: Graphite Anodesmentioning

confidence: 99%

Section: Graphite Anodesmentioning

confidence: 99%

Recent Progress and Perspective in Electrode Materials for K‐Ion Batteries

Kim

Bianchini

et al. 2017

Advanced Energy Materials

601

465

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“…It was suggested that this difference in 44 reactivity was caused by the fact that the suspensions formed by KC8 in n-pentane and Et2O are not as well dispersed as those formed in THF (Bergbreiter and Killough, 1978). Potassium graphite (commonly referred to as KC8) is the most potassium rich form of a series of graphite intercalation compounds with potassium (Rüdorff and Schulze, 1954). A spacefilling model of KC8 is shown in Figure 10.…”

Section: Reaction Conditions For Reduction Chemistrymentioning

confidence: 99%

Rare Earth Arene-Bridged Complexes Obtained by Reduction of Organometallic Precursors

Huang

Diaconescu

2014

Including Actinides

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Rare earth chemistry has witnessed remarkable advances in recent years. In particular, ancillary ligands other than cyclopentadienyl derivatives have been introduced to the organometallic chemistry and their complexes exhibit distinct reactivity and properties compared to the metallocene or half-sandwiched analogues. The present chapter reviews arene-bridged rare earth complexes with an emphasis on those compounds obtained by reduction reactions. A particular emphasis is placed on rare earth complexes supported by 1,1′-ferrocenediyl diamides since they show the most diverse chemistry with arenes: fused arenes, such as naphthalene and anthracene, formed inverse-sandwiched complexes, in which the arene is dianionic; weakly conjugated arenes, such as biphenyl, p-terphenyl, and 1,3,5-triphenylbenzene, were unexpectedly reduced by four electrons and led to 6-carbon, 10- electron aromatic systems; on the contrary, (E)-stilbene, which has a carbon-carbon double bond between the two phenyl rings, could only be reduced by two electrons, which were located on the carbon-carbon double bond instead of the phenyl rings.

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“…1 Introduction Graphite intercalation compounds (GICs) have long been the focus of vast research, from which one of the first models presented was KC 8 , a potassium intercalated graphite system introduced by Rüdorff and Schulze in 1954 [1]. Most of the early work was performed using X-ray diffraction (XRD) to determine the structural information on the staging, molecular intercalant structure, layer separation, and in plane densities [2].…”

mentioning

confidence: 99%

Defect modulated Raman response of KC₈ single crystals

Chacón-Torres

Pichler

2011

Physica Status Solidi (b)

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In situ experiments of graphite intercalation with potassium have been performed under high vacuum (HV) conditions. A detailed Raman lineshape analysis of the G‐line was applied to determine the intrinsic response of the stage one KC8 compound. Four defect‐modulated graphite single crystals were analyzed. We observe five vibrational modes (∼560, 1260, 1510, 1547, and 1563 cm−1). From a Breit–Wigner–Fano (BWF) lineshape analysis we elucidate the contribution of each vibrational mode observed. The intensity of the z‐axis mode (CZ) around ∼560 cm−1 varies depending on the defect modulated nominal KC8 crystal chosen. We prove that the intrinsic G‐line of KC8 is at 1510 cm−1, and it is strongly dependent on the actual defect content in the sample, which has important implications for the electron phonon coupling (EPC) responsible of superconductivity in this system.

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Über Alkaligraphitverbindungen

Cited by 234 publications

References 5 publications

Recent Progress and Perspective in Electrode Materials for K‐Ion Batteries

Recent Progress and Perspective in Electrode Materials for K‐Ion Batteries

Rare Earth Arene-Bridged Complexes Obtained by Reduction of Organometallic Precursors

Defect modulated Raman response of KC₈ single crystals

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Über Alkaligraphitverbindungen

Cited by 234 publications

References 5 publications

Recent Progress and Perspective in Electrode Materials for K‐Ion Batteries

Recent Progress and Perspective in Electrode Materials for K‐Ion Batteries

Rare Earth Arene-Bridged Complexes Obtained by Reduction of Organometallic Precursors

Defect modulated Raman response of KC8 single crystals

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Product

Resources

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Defect modulated Raman response of KC₈ single crystals