One-Pot Synthesis of Tin-Embedded Carbon/Silica Nanocomposites for Anode Materials in Lithium-Ion Batteries

We report a facile “one-pot” method for the synthesis of Sn-embedded carbon–silica (CS) mesostructured (nanostructured) composites through the selective interaction of resol (carbon precursor), tetraethylorthosilicate (TEOS), and tributylphenyltin (Sn precursor) with an amphiphilic diblock copolymer, poly(ethylene oxide-<i>b</i>-styrene), PEO-<i>b</i>-PS. A unique morphology transition from Sn nanowires to spherical Sn nanoparticles embedded in CS framework has been obtained. Metallic Sn species are homogeneously embedded in a rigid CS framework and are effectively confined within the nanostructures. The resulting composites are used as anode materials for lithium-ion batteries and exhibit high specific capacities (600 mA h g ^–1 at a current density of 45 mA g^–1, and 440 mA h g^–1 at a current density of 300 mA g^–1) and an excellent cyclability of over 100 cycles with high Coulombic efficiency. Most of all, the novel method developed in this work for synthesizing functional hybrid materials can be extended to the preparation of various functional nanocomposites owing to its versatility and facileness

P2 Orthorhombic Na_0.7[Mn_1–<i>x</i>Li_<i>x</i>]O_2+<i>y</i> as Cathode Materials for Na-Ion Batteries

P2-type manganese-based oxide materials have received attention as promising cathode materials for sodium ion batteries because of their low cost and high capacity, but their reaction and failure mechanisms are not yet fully understood. In this study, the reaction and failure mechanisms of β-Na_0.7[Mn_1–<i>x</i>Li_<i>x</i>]­O_2+<i>y</i> (<i>x</i> = 0.02, 0.04, 0.07, and 0.25), α-Na_0.7MnO_2+<i>y</i>, and β-Na_0.7MnO_2+<i>z</i> are compared to clarify the dominant factors influencing their electrochemical performances. Using a quenching process with various amounts of a Li dopant, the Mn oxidation state in β-Na_0.7[Mn_1–<i>x</i>Li_<i>x</i>]­O_2+<i>y</i> is carefully controlled without the inclusion of impurities. Through various in situ and ex situ analyses including X-ray diffraction, X-ray absorption near-edge structure spectroscopy, and inductively coupled plasma mass spectrometry, we clarify the dependence of (i) reaction mechanisms on disordered Li distribution in the Mn layer, (ii) reversible capacities on the initial Mn oxidation state, (iii) redox potentials on the Jahn–Teller distortion, (iv) capacity fading on phase transitions during charging and discharging, and (v) electrochemical performance on Li dopant vs Mn vacancy. Finally, we demonstrate that the optimized β-Na_0.7[Mn_1–<i>x</i>Li_<i>x</i>]­O_2+<i>y</i> (<i>x</i> = 0.07) exhibits excellent electrochemical performance including a high reversible capacity of ∼183 mA h g^–1 and stable cycle performance over 120 cycles

Cointercalation of Mg²⁺ Ions into Graphite for Magnesium-Ion Batteries

Cointercalation of Mg²⁺ Ions into Graphite for Magnesium-Ion Batterie

Magnesium(II) Bis(trifluoromethane sulfonyl) Imide-Based Electrolytes with Wide Electrochemical Windows for Rechargeable Magnesium Batteries

We present a promising electrolyte candidate, Mg­(TFSI)₂ dissolved in glyme/diglyme, for future design of advanced magnesium (Mg) batteries. This electrolyte shows high anodic stability on an aluminum current collector and allows Mg stripping at the Mg electrode and Mg deposition on the stainless steel or the copper electrode. It is clearly shown that nondendritic and agglomerated Mg secondary particles composed of ca. 50 nm primary particles alleviating safety concern are formed in glyme/diglyme with 0.3 M Mg­(TFSI)₂ at a high rate of 1C. Moreover, a Mg­(TFSI)₂-based electrolyte presents the compatibility toward a Chevrel phase Mo₆S₈, a radical polymer charged up to a high voltage of 3.4 V versus Mg/Mg²⁺ and a carbon–sulfur composite as cathodes

Co-intercalation of Mg²⁺ and Na⁺ in Na_0.69Fe₂(CN)₆ as a High-Voltage Cathode for Magnesium Batteries

Thanks to the advantages of low cost and good safety, magnesium metal batteries get the limelight as substituent for lithium ion batteries. However, the energy density of state-of-the-art magnesium batteries is not high enough because of their low operating potential; thus, it is necessary to improve the energy density by developing new high-voltage cathode materials. In this study, nanosized Berlin green Fe₂(CN)₆ and Prussian blue Na_0.69Fe₂(CN)₆ are compared as high-voltage cathode materials for magnesium batteries. Interestingly, while Mg²⁺ ions cannot be intercalated in Fe₂(CN)₆, Na_0.69Fe₂(CN)₆ shows reversible intercalation and deintercalation of Mg²⁺ ions, although they have the same crystal structure except for the presence of Na⁺ ions. This phenomenon is attributed to the fact that Mg²⁺ ions are more stable in Na⁺-containing Na_0.69Fe₂(CN)₆ than in Na⁺-free Fe₂(CN)₆, indicating Na⁺ ions in Na_0.69Fe₂(CN)₆ plays a crucial role in stabilizing Mg²⁺ ions. Na_0.69Fe₂(CN)₆ delivers reversible capacity of approximately 70 mA h g^–1 at 3.0 V vs Mg/Mg²⁺ and shows stable cycle performance over 35 cycles. Therefore, Prussian blue analogues are promising structures for high-voltage cathode materials in Mg batteries. Furthermore, this co-intercalation effect suggests new avenues for the development of cathode materials in hybrid magnesium batteries that use both Mg²⁺ and Na⁺ ions as charge carriers

Two-Dimensional Phosphorene-Derived Protective Layers on a Lithium Metal Anode for Lithium-Oxygen Batteries

Lithium-oxygen (Li-O₂) batteries are desirable for electric vehicles because of their high energy density. Li dendrite growth and severe electrolyte decomposition on Li metal are, however, challenging issues for the practical application of these batteries. In this connection, an electrochemically active two-dimensional phosphorene-derived lithium phosphide is introduced as a Li metal protective layer, where the nanosized protective layer on Li metal suppresses electrolyte decomposition and Li dendrite growth. This suppression is attributed to thermodynamic properties of the electrochemically active lithium phosphide protective layer. The electrolyte decomposition is suppressed on the protective layer because the redox potential of lithium phosphide layer is higher than that of electrolyte decomposition. Li plating is thermodynamically unfavorable on lithium phosphide layers, which hinders Li dendrite growth during cycling. As a result, the nanosized lithium phosphide protective layer improves the cycle performance of Li symmetric cells and Li-O₂ batteries with various electrolytes including lithium bis­(trifluoromethanesulfonyl)­imide in <i>N,N</i>-dimethylacetamide. A variety of <i>ex situ</i> analyses and theoretical calculations support these behaviors of the phosphorene-derived lithium phosphide protective layer

Two Years after the <i>Hebei Spirit</i> Oil Spill: Residual Crude-Derived Hydrocarbons and Potential AhR-Mediated Activities in Coastal Sediments

The <i>Hebei Spirit</i> oil spill occurred in December 2007 approximately 10 km off the coast of Taean, South Korea, on the Yellow Sea. However, the exposure and potential effects remain largely unknown. A total of 50 surface and subsurface sediment samples were collected from 22 sampling locations at the spill site in order to determine the concentration, distribution, composition of residual crudes, and to evaluate the potential ecological risk after two years of oil exposure. Samples were extracted and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs), 20 alkyl-PAHs, 15 aliphatic hydrocarbons, and total petroleum hydrocarbons using GC-MSD. AhR-mediated activity associated with organic sediment extracts was screened using the H4IIE-<i>luc</i> cell bioassay. The response of the benthic invertebrate community was assessed by mapping the macrobenthic fauna. Elevated concentrations of residual crudes from the oil spill were primarily found in muddy bottoms, particularly in subsurface layers. In general, the bioassay results were consistent with the chemistry data in a dose-dependent manner, although the mass-balance was incomplete. More weathered samples containing greater fractions of alkylated PAHs exhibited greater AhR activity, due to the occurrence of recalcitrant AhR agonists present in residual oils. The macrobenthic population distribution exhibits signs of species-specific tolerances and/or recolonization of certain species such as <i>Batillaria</i> during weathering periods. Although the <i>Hebei Spirit</i> oil spill was a severe oil exposure, it appears the site is recovering two years later