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Two-dimensional (2D) "graphene-like" inorganic materials, because of the short lithium ion diffusion path and unique 2D carrier pathways, become a new research focus of the lithium storages. Some "graphene-like" binary compounds, ...
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Two-dimensional (2D) "graphene-like" inorganic materials, because of the short lithium ion diffusion path and unique 2D carrier pathways, become a new research focus of the lithium storages. Some "graphene-like" binary compounds, such as, MnO2, MoS2 and VO2 ultrathin nanosheets, have been synthesized by the peeling method, which also exhibit enhanced lithium storage performances. However, it still remains a great challenge to synthesize widely-used lithium-containing ternary oxides with "graphene-like" nanostructures, because the lithium-containing ternary oxides, unlike ternary layered double hydroxides (LDH), are very hard to be directly peeled. Herein, we successfully synthesized ultrathin Li3VO4 nanoribbons with a thickness of about 3 nm by transformation from ultrathin V2O5 xH(2)O nanoribbons, moreover, we achieved the preparation of ultrathin Li3VO4 nanoribbon@graphene sandwich-like nanostructures (LVO/G) through the layer-by-layer assembly method. The unique sandwich-like nanostructures shows not only a high specific reversible capacitance (up to 452.5 mA h g(-1) after 200 cycles) but also an excellent cycling performance (with more than 299.2 mA h g(-1) of the capacity at 10C after 1000 cycles) as well as very high rate capability. Such template strategy, using "graphene-like" binary inorganic nanosheets as templates to synthesize lithium-containing ternary oxide nanosheets, may be extended to prepare other ternary oxides with "graphene-like" nanostructures. (C) 2015 Elsevier Ltd. All rights reserved.
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Iodine-containing, cation-deficient, lithium manganese oxides (ICCD-LMO) are prepared by reaction of MnO_2 with LiI. The MnO_2 is completely transformed into spinel-structured compounds with a nominal composition of Li_(1-δ)Mn_(2...
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Iodine-containing, cation-deficient, lithium manganese oxides (ICCD-LMO) are prepared by reaction of MnO_2 with LiI. The MnO_2 is completely transformed into spinel-structured compounds with a nominal composition of Li_(1-δ)Mn_(2-2δ)O_4I_x. A sample prepared at 800℃, viz. Li_(0.99)Mn_(1.98)O_4I_(0.02), exhibits an initial discharge capacity of 113 mA h g~(-1) with good cycleability and rate capability in the 4-V region. Iodine-containing, lithium-rich lithium manganese oxides (ICLR-LMO) are also prepared by reaction of LiMn_2O_4 with LiI, which results in a nominal composition of Li_(1+x)Mn_(2-x)O_4I_x. Li_(1.01)Mn_(1.99)O_4I_(0.02) shows a discharge capacity of 124 mA h g~(-1) on the first cycle and 119 mA h g~(-1) a on the 20th cycle. Both results indicate that a small amount of iodine species helps to maintain cycle performance.
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Abstract Lithium‐rich manganese‐based cathode materials are considered ideal for the next‐generation lithium‐ion power batteries due to their high specific capacity. However, their widespread commercial deployment has received...
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Abstract Lithium‐rich manganese‐based cathode materials are considered ideal for the next‐generation lithium‐ion power batteries due to their high specific capacity. However, their widespread commercial deployment has received serious limitations, such as low initial coulombic efficiency (ICE), severe voltage and capacity degradation. To solve these issues, the surface of Li‐rich layered oxide (LLO) material is uniformly coated with a layer of ternary lithium‐rare earth oxides LiErO2 by synchronous lithium strategy. The LiErO2‐coated material exhibits higher capacity retention of 83.79?% with 182.7?mAh?g?1 compared with that of the pristine material, which retained 60.54?% with 144.1?mAh?g?1 after 200 cycles at 0.5?C. The excellent electrochemical performance is owing to the high Li+ conductivity of the LiErO2 coating which enhanced the lithiation kinetics of the material, and X‐ray photoelectron spectrometer (XPS) results indicate coating layer has abundant oxygen vacancies that facilitate reversible redox processes of oxygen. Meanwhile, the results of high resolution transmission electron microscope (HRTEM) and XPS analyses of the materials after cycling shows the uniform coating can suppress the side reactions between the electrode and electrolyte during long‐term cycling, reduce the phase transition of the surface structure, and enhance interfacial stability. This work provides innovative ideas for the design of lithium‐rich cathode materials.
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Selective lithium recovery from spent lithium-ion batteries (LIBs) is attracting attention due to the large consumption of lithium for battery manufacturing. In this work, a novel method is proposed for selective extraction of lit...
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Selective lithium recovery from spent lithium-ion batteries (LIBs) is attracting attention due to the large consumption of lithium for battery manufacturing. In this work, a novel method is proposed for selective extraction of lithium from spent ternary nickel-cobalt-manganese (NCM) LIBs under near-neutral pH and oxidative conditions by using NaClO as oxidant. The results shows that NaClO addition is the key to realize the selective extraction of lithium from the layered NCM structure under a non-acidic environment. Interestingly, the cracking and phase transition of spent cathode particles, which generally occur during electrochemical degradation, were also observed via NaClO oxidation in this work. Due to the unique properties of the spent NCM cathode particles, NaClO was activated catalytically in situ and generated highly active, electrophilic oxygen species such as 'OH, ~1O2, and ·O2~-, which were confirmed by quenching experiments. Their generation can further facilitate the oxidation/de-lithiation process and improve lithium extraction efficiency. As a result, approximately 92.54% of lithium was leached out from spent NCM cathode materials with >99% selectivity under the optimized leaching conditions (20 g/L solid-to-liquid ratio, 8% NaClO volume fraction, pH 7-8, 6 h, and room temperature). The purity of recovered Li2CO3 can reach to around 99.02% in the absence of purification process. The proposed method is operationally simple and safe because it is performed under near-neutral conditions (pH 7-8) and room temperature. Furthermore, NaClO is inexpensive, making this method attractive for application.
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Synthesis of nanostructures with pre-designed morphology has recently gained tremendous research attention for achieving enhanced performance. Herein, we report synthesis of hetero-dimensional hybrid nanostructure of Fe-2(MoO4)(3)...
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Synthesis of nanostructures with pre-designed morphology has recently gained tremendous research attention for achieving enhanced performance. Herein, we report synthesis of hetero-dimensional hybrid nanostructure of Fe-2(MoO4)(3) consisting of nanorods (length 90-170 nm, dia similar to 30 nm) in which spherical nanoparticles (dia 5-10 nm) are embedded. We also report the electrochemical properties of synergic Fe-2(MoO4)(3)/MWCNT composites as lithium-ion battery anode for the first time. Here, 1D Fe-2(MoO4)(3) nanorods serve as a strain accommodative matrix imparting stability while the entrenched OD Fe-2(MoO4)(3) nanoparticles offer a large number of active sites yielding high capacity. Due to high surface to volume ratio of the composites, the Li+ ion diffusion length is shortened leading to a faster kinetics and improved the rate performance. Moreover, MWCNT provides an effective conduction network for electron transport during lithiation/delithiation process and at the same time, serves as a strain-buffer preserving mechanical integrity of the composite electrode. This three-way strategy results in a specific capacity of 1321 mAh g(-1) for a 50:50 wt% composite of Fe-2(MoO4)(3) and MWCNT. Even at a high current density of 1.0 mA cm(-2) (1200 mA g(-1)), capacity of 600 mAh g(-1) could be obtained. Further, 82% retention of capacity is observed after 200 cycles at 0.1 mA cm(-2). Importantly, no appreciable change in morphology is observed with discharge-charge cycling. (C) 2016 Elsevier B.V. All rights reserved.
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The SnO2-MoO3-C composite anode for Li-ion batteries (LIBs) was produced via simple hydrothermal synthesis and dry ball milling. In this hybrid, nanosized-SnO2/MoO3 nanoparticles were encapsulated in plate-like graphite. MoO3 addi...
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The SnO2-MoO3-C composite anode for Li-ion batteries (LIBs) was produced via simple hydrothermal synthesis and dry ball milling. In this hybrid, nanosized-SnO2/MoO3 nanoparticles were encapsulated in plate-like graphite. MoO3 additive can protect Sn from aggregating and accelerate the reversible conversion reaction (Sn/Li2O hybrid transformation into SnO2). The SnO2-MoO3-C displays high initial coulombic efficiency of 70% (average for five cells), high reversible specific capacity of 1338.3 mAhg(-1) at 0.2 A g(-1) after 300 cycles, superior rate capacity of 715.08 mAhg(-1) at 5 A g(-1) and long-term cyclic stability, with capacity of 571.9 mAhg(-1) at 2.0 A g(-1) after 1000 cycles. Owing to its superior performance and simple synthesis, the SnO2-MoO3-C composite is a promising anode material for LIBs.
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In order to develop a secondary battery with high energy density, several characteristics of coin-type cells using lithium-containing manganese dioxide as a positive material are investigated. Cells prepared from LiOH and electrol...
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In order to develop a secondary battery with high energy density, several characteristics of coin-type cells using lithium-containing manganese dioxide as a positive material are investigated. Cells prepared from LiOH and electrolytic manganese dioxide (EMD) display higher energy density (177 Wh l~(-1); 63 Wh kg~(-1)) than those prepared from LiOH and chemical manganese dioxide (CMD). LiOH·EMD has better cycle characteristics and storage characteristics than LiOH·CMD. Lithium-containing manganese dioxide (LiOH·EMD)/Li-Al batteries have high reliability against overcharge and overdischarge.
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The catalytic performance for the oxidative coupling of methane (OCM) over chloride-containing Li/SnO~(2)was investigated experimentally and the mechanism of OCM was further suggested. Cl_(?)ions exerted remarkable influence on th...
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The catalytic performance for the oxidative coupling of methane (OCM) over chloride-containing Li/SnO~(2)was investigated experimentally and the mechanism of OCM was further suggested. Cl_(?)ions exerted remarkable influence on the catalytic performance of Li/SnO~(2), with that at 750?°C displaying the highest catalytic activity (18.5% C~(2)yield) for OCM. The prepared catalysts were characterized with N~(2)physisorption, X-ray diffraction, O~(2)-temperature programmed desorption, X-ray photoelectron spectroscopy and H~(2)temperature programmed reduction measurement to elucidate the effect of Cl_(?)ions on its properties and catalytic performance. The results showed that the enhanced OCM catalytic activity of the chloride-containing Li/SnO~(2)catalysts compared with pure Li/SnO~(2)catalyst may originate from the higher concentration of anion vacancies, more rapid oxygen mobility and improved redox ability of tin. In addition, characterization by CO~(2)-temperature programmed desorption, infrared spectroscopy and O~(2)frequency pulse reactions results illustrated that adding Cl_(?)ions improved performance of Li/SnO~(2), which not only reduced strong basic sites to prevent the formation of poisoning carbonate, but also facilitated the formed chloromethane to convert quickly to ethylene.
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Transition-metal oxides have been widely explored as the anode materials for lithium-ion batteries (LIBs) because of its low cost and high energy/power density. However, the electrode pulverization and capacity fading during cycli...
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Transition-metal oxides have been widely explored as the anode materials for lithium-ion batteries (LIBs) because of its low cost and high energy/power density. However, the electrode pulverization and capacity fading during cycling lead to poor cycling performance. Herein, ultrathin ZnCo2O4 nanosheets with desired mesoporosity and high surface area are prepared by a facile hydrothermal approach. Such ZnCo2O4 nanostructures show excellent lithium storage performance as anode materials for LIBs. At a current density of 1 A g(-1), the ultrathin ZnCo2O4 nanosheets present an initial specific capacity of 1251 mAh g(-1) and the specific capacity remains at 810 mAh g-1 even after 200 discharge charge cycles. (C) 2017 Elsevier Inc. All rights reserved.
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The charging and discharge characteristics of electrodes based on LiNi0.8Co0.15Al0.05O2 (NCA) and Li4Ti5O12 (LTO) are studied in LiClO4 solutions in a mixture of propylene carbonate and dimethoxyethane at the temperature from -45 ...
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The charging and discharge characteristics of electrodes based on LiNi0.8Co0.15Al0.05O2 (NCA) and Li4Ti5O12 (LTO) are studied in LiClO4 solutions in a mixture of propylene carbonate and dimethoxyethane at the temperature from -45 to +60 degrees C. For both materials, the discharge capacity decreases with the current increase and its dependence cannot be described by the Peukert equation. The decrease in the temperature results also in the increase in polarization, the effective energy of activation being 52 kJ/mol on the NCA electrode and only 23 kJ/mol on the LTO electrode. The possibility of using batteries based on the NCA-LTO system at the temperature down to -40 degrees C is confirmed.
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