12,133 research outputs found
Maximum Li storage in Si nanowires for the high capacity threedimensional Li-ion battery
No full textNanowires can serve as three-dimensional platforms at the nanometer scale for highly efficient chemical energy storage and conversion vehicles, such as fuel cells and secondary batteries. Here we report a coin-type Si nanowire (NW) half-cell Li-ion battery showing the Li capacity of approximately 4000 mAh/g, which nearly approaches the theoretical limit of 4200 mAh/g, with very high Coulombic efficiency of up to 98%. Concomitantly, we provide direct evidence of reversible phase transitions in the Si NW anodes at the full electrochemical cycles, varying from pure Si to Li(22)Si(5) phase, which has been known empirically inaccessible in the bulk limit.open11117sciescopu
Upcycling of nickel oxide from spent Ni-MH batteries as ultra-high capacity and stable Li-based energy storage devices
No full textDue to the rapid expansion of portable electronics and electric vehicles market, the projected demand of rechargeable batteries is huge and may lead to shortage of critical minerals, especially nickel (Ni) metal. In the present study, we upcycled NiO material from spent Nickel–Metal hydride batteries (Ni-MH) as electrodes in Li-ion battery (LIB) and supercapacitor. Intriguingly, recycled NiO was applied successfully to develop sustainable LiNi0.5Mn1.5O4 (LNMO) cathode, delivering the promising capacity. As the recovered NiO-anode in LIBs, the device exhibited ultrahigh capacity of 1248 mAh g−1 at 0.1C, exhibiting excellent rate capability and cycle life in traditional carbonate-based electrolyte. The full cell with NMC cathode gave a high discharged capacity of 137.4 mAh/g. Addition to conventional electrolyte, a safe and non-flammable diglyme electrolyte using recovered NiO was investigated under identical condition. The maximum reversible capacity of 642 mAh g−1 at 0.1C was achieved along with good rate performance. Likewise, the NiO-based supercapacitor electrode delivered a maximum capacitance of 106C g−1 at 0.5 A g−1. Hence, upcycling of abundant NiO waste as low-cost electrode materials from end-of-life batteries paves the way for future generation of Li-based energy storage devices and sustainable supply of critical minerals and clean environment
Atomic structure of alkali metal (Li, Na, K) adsorbed Ge(111)-(3x1) surfaces
No full textWe have studied the atomic structure of alkali metal (AM) adsorbed Ge(111)-(3x1) surfaces using the pseudopotential and density-functional theory. Our total-energy calculations for Li, Na, and K demonstrate that the AM/Ge(111)-(3x1) surfaces have the same ground-state structure as the AM/Si(111)-(3x1) surfaces, which is referred to as the honeycomb-chain-channel model, and show systematic variations in surface bonding geometry over the AM adsorbates. Details of the structural changes are reported and discussed in connection to the questions raised by recent scanning tunneling microscopy and x-ray photoelectron spectroscopy studies.open1119sciescopu
Hierarchical SiOx nanoconifers for Li-ion battery anodes with structural stability and kinetic enhancement
No full textSilicon sub-oxides, SiOx (0 < x < 1) can be regarded as a promising anode material for high performance Li-ion batteries for its unique electrochemical reactions to Li. We designed and synthesized the columnar-shape SiOx nanoconifers (0.9 < x < 1), directly self-organized on metallic NiSix nanowires (NWs) for its anodic use in Li rechargeable batteries. The half-cell incorporating SiOx nanoconifers/NiSix NW heterostructures displays good cyclic retention and rate capability, which are attributed to the structural and kinetic stability of the hierarchical SiOx nanoconifers rigidly supported by metallic NiSix core NWs by providing a reversible electrochemical route with a lower activation energy. (C) 2012 Elsevier B.V. All rights reserved.X113836sciescopu
Structural properties of alkali metals (Li, Na and K) in the generalized gradient approximation
No full textWe have studied the structural properties and the phase stability of the alkali metals (Li, Na, and K) by using the pseudopotential density-functional total-energy calculation scheme within the recently proposed generalized-gradient approximation (GGA) of Perdew, Burke, and Ernzerhof. The present GGA calculations predict the lattice constants, the bulk moduli, and the cohesive energies of the alkali metals more accurately than the local-density approximation calculations! but the order of the crystal energy at zero temperature is E-hcp < E-fcc < E-bcc for all these metals, irrespective of the exchange-correlation functionals used.X113sciescopu
Postnatal exposure of 2,2’,3,3’,4,6’- hexachlorobiphenyl and 2,2’,3,4’,5’,6-hexachlorobiphenyl on sperm function and hormone levels in adult rats.
No full textHepatic enzyme induction and acute endocrine effects of 2,2’,3,3’,4,6’-hexachlorobiphenyl and 2,2’,3,4’,5’,6-hexachlorobiphenyl in prepubertal female rats.
No full textEffects of acute postnatal exposure to 3,3’,4,4’-tetrachlorobiphenyl on sperm function and hormone levels in adult rats.
No full textPyrometallurgical recycling of Li-ion, Ni–Cd and Ni–MH batteries: A minireview
No full textThis brief article review discusses the available pyrometallurgical methods for recycling of rechargeable batteries including Li-ion, Ni–Cd and Ni–MH batteries. Owing to the exponentially growing interest for using portable electronic devices and vehicles, rechargeable batteries have attracted significant attention in recent years, resulting in an increasing demand for critical metals such as Li, Co, Ni, rare earth elements. Because most of the published review articles have been investigated the hydrometallurgical methods, in this minireview, the current status of battery recycling, pretreatment, and especially pyrometallurgical methods of recycling of the rechargeable batteries are summarized
Thermal runaway and battery fire: comparison of Li-ion, Ni-MH and sealed lead-acid batteries
No full textRechargeable batteries are a key component for sustainable mobility. The last years showed a significant reduction of price and increase in energy density of Li-ion batteries for electric vehicles. Unfortunately, batteries with high energy density can be source of hazard. Recently, burning Li-ion batteries of mobile-phones got a lot of negative attention in the media.
In the first part of the paper we review the hazards of conventional Ni-MH and sealed lead-acid batteries. In the second part we focus on Li-ion batteries: we introduce different cell geometries and electrode types, we show a test-stand designed to measure thermal runaway characteristics in our laboratory and finally we conclude with results of a real thermal runaway experiment
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