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Abstract: Uniformly loaded α-Fe2O3/graphene nanocomposites are synthesized via hydrothermal routs. Enhanced lithium storage performance of lithium-ion battery anodes is realized from α-Fe2O3/graphene nanocomposites. Compared with pure α-Fe2O3 nanostructures, α-Fe2O3/graphene nanocomposites exhibit higher reversible capacity and better cycling performance. Their reversible capacity is up to 771 mA h g−1 at C/10 rate, and maintains 73% after 30 cycles. Such behaviors can be attributed to high electron and Li-ion conductivity, large surface area, good mechanical flexibility of graphene nanosheets and the synergetic effect of graphene and α-Fe2O3 nanostructures. Our results indicate that α-Fe2O3/graphene nanocomposites are good candidates for high performance lithium-ion battery anodes. [Copyright &y& Elsevier]

As a class of redox active materials with some preferable properties, including rigid structure, insoluble characters, and large amounts of nitrogen atoms, covalent triazine frameworks (CTFs) have been frequently adopted as electrode materials in Lithium-ion batteries (LIBs). Herein, a triazine-based covalent organic framework employing 3,4-ethylenedioxythiophene (EDOT) as the bridging unit is synthesized by the presence of carbon powder through Stille coupling reaction. The carbon powder was added in an in-situ manner to overcome the low intrinsic conductivity of the polymer, which led to the formation of the polymer@C composite (PTT-O@C, PTT-O is a type of CTFs). The composite material is then employed in LIBs as anode material. The designed polymer shows a narrow band gap of 1.84 eV, proving the effectiveness of the nitrogen-enriched triazine unit in reducing the band gap of the resultant polymers. The CV results showed that the redox potential of the composite (vs. Li/Li+) is around 1.0 V, which makes it suitable to be used as the anode material in lithium-ion batteries. The composite material could exhibit the stable specific capacity of 645 mAh/g at 100 mA/g and 435 mAh/g at 500 mA/g, respectively, much higher than the pure carbon materials, indicating the good reversibility of the material. This work provides some additional information on electrochemical performance of the triazine and EDOT based CTFs, which is helpful for developing a deep understanding of the structure–performance correlations of the CTFs as anode materials. [ABSTRACT FROM AUTHOR]

Pomegranate-shaped Sn/SnO x /nanocarbon composites are fabricated via a simple one-step solvothermal method. The Sn and SnO x nanoparticles are uniformly embedded in the sheet-like nanocarbon membranes. As the anode of lithium-ion battery, the pomegranate-shaped Sn/SnO x /nanocarbon composites exhibit ultrafast-charging and long-life performance. At super high current rate of 10 C, 15 C and 20 C (the charging process is shortened to merely 6, 4 and 3 min, respectively), the reversible capacity of pomegranate-shaped Sn/SnO x /nanocarbon composites is 545, 467 and 421 mAh g −1 , respectively. After 2000 cycles, the capacity can still maintain at 192, 139 and 101 mAh g −1 at 10 C, 15 C and 20 C rate, respectively. Even after 5000 cycles at 15 C rate, the discharge capacity can still keep at 135 mAh g −1 . Such superior performance can be attributed to the unique structure, good electronic conductivity, short paths for lithium diffusion and interfacial charging mechanism. The present results indicate a new way to produce pomegranate-shaped metal/metal-oxide/nanocarbon composites with ultrafast-charging/long-life lithium-storage performance. [ABSTRACT FROM AUTHOR]

CoMoO 4 /Fe 2 O 3 core-shell nanorods are synthesized by a two-step hydrothermal method, and Fe 2 O 3 nanoparticles as shell are uniformly distributed on the whole surface of CoMoO 4 nanorods. The core-shell nanorods as the anode of lithium-ion battery exhibit high reversible capacity of 1354 mAh g −1 at 0.2 C rate (5 h per half cycle), which is higher than that of bare CoMoO 4 nanorods. The discharge capacity can still maintain at 1335 mAh g −1 (after 50 cycles) and 1236 mAh g −1 (after 100 cycles). The capacity retention between 2nd and 50th cycles is up to 98.6%. The superior lithium-storage performance can be owned to the stable crystal structure, good electrical conductivity and complex synergistic effect between CoMoO 4 and Fe 2 O 3 . The present results indicate that CoMoO 4 /Fe 2 O 3 core-shell nanorods are promising candidates for the anode of lithium-ion battery. [ABSTRACT FROM AUTHOR]

The present work demonstrates that lithium ions can be stepwise substituted by protons from spinel Li 4 Ti 5 O 12 crystalline particles though simple ion-exchange in aqueous HCl solution with the aid of heat treatment. This enables us to continuously tune the Li-to-Ti stoichiometric ratios from 0.80 to 0.59, 0.41, 0.21, 0.15, and 0.09, thus transforming Li 4 Ti 5 O 12 to Li 4−x Ti 5 O 12 nanocrystals. The resulting nanocrystals maintain the spinel crystal structure when x becomes smaller than 3. Among as-prepared the Li 4−x Ti 5 O 12 crystalline particles, Li 1 Ti 5 O 12 shows the highest capacity of 193 mAh g −1 at 1C and 148 mAh g −1 at 20C, lower current impedance (47 Ω), significantly improved rate capability and fairly long cycle life. This excellent electrochemical performance makes spinel Li 4−x Ti 5 O 12 particles as a promising anode candidate for lithium ion batteries superior. [ABSTRACT FROM AUTHOR]

α-MoO 3 @MnO 2 core-shell nanorods are synthesized via a facile two-step method. The electrochemical measurement of lithium-ion batteries (LIBs) shows that prepared α-MoO 3 @MnO 2 core-shell nanorods as the anode exhibit high discharge capacity, high rate capability, and excellent cycling stability. The reversible capacity of α-MoO 3 @MnO 2 core-shell nanorods is 1475 mAh/g at 0.1 C rate (10 hours per charging cycle) and retains at 1127 mAh/g after 50 cycles, much higher than that of pure α-MoO 3 and MnO 2 . Even at high current rate of 6 C, the reversible capacity of α-MoO 3 @MnO 2 core-shell nanorods is 394 mAh/g and retains at 286 mAh/g after 50 cycles. Our results indicate that α-MoO 3 @MnO 2 core-shell nanocomposites have enormous potential for application in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: SnS2–graphene nanocomposites are synthesized by a hydrothermal method, and their application as anodes of lithium-ion batteries has been investigated. SnS2 nanosheets are uniformly coating on the surface of graphene. SnS2–graphene nanocomposites exhibit high cyclability and capacity. The reversible capacity is 766 mAh/g at 0.2C rate and maintains at 570 mAh/g after 30 cycles. Such a high performance can be attributed to high electron and Li-ion conductivity, large surface area, good mechanical flexibility of graphene nanosheets and the synergetic effect between graphene and SnS2 nanostructures. The present results indicate that SnS2–graphene nanocomposites have potential applications in lithium-ion battery anodes. [Copyright &y& Elsevier]

Abstract: FeWO4-SnO2 core-shell nanorods are assembled via a two-step method. SnO2 nanoparticles are uniformly coated on the surface of FeWO4 nanorods. And high lithium storage performance has been achieved from them. At C/10 rate (10hours per charging cycle), the reversible capacity (the 2nd cycle) of FeWO4-SnO2 core-shell nanorods is up to 1286.9 mAh g−1, much higher than that of FeWO4 nanorods, SnO2 and traditional theoretical results. Such behaviour is attributed to the synergistic effect between nanostructured SnO2 and FeWO4. Our results imply that core-shell nanocomposites are good candidates for high-capacity anodes of lithium ion battery. [Copyright &y& Elsevier]

Abstract: SnO2–MnO2–SnO2 sandwich-structured nanotubes are synthesized by uniformly coating SnO2 nanoparticles on both the inner and outer walls of α-MnO2 nanotubes via a simple wet-chemical route. As the anodes of lithium ion batteries, SnO2–MnO2–SnO2 sandwich-structured nanotubes exhibit high reversible capacity, cyclability and rate capability. The reversible capacity of the nanocomposites is 847.5mAh/g and retains 716.0mAh/g after 50 cycles, which is higher than that of α-MnO2 or SnO2. At 20C rate, SnO2–MnO2–SnO2 sandwich-structured nanotubes can deliver a capacity of 224.2mAh/g. Such excellent performances can be attributed to the synergistic effect and the tubular nanostructures. Our results imply that one-dimensional sandwich-structured nanocomposites have potential applications in lithium ion batteries. [Copyright &y& Elsevier]

Abstract: SnO2/NiO core-shell nanobelts have been synthesized simply by coating NiO nanobelts with a thin layer of SnO2 nanoparticles. As the anode material of lithium-ion battery, SnO2/NiO core-shell nanobelts exhibit higher reversible capacity (∼900mAh/g at C/20 rate) and better cycling performance than individual NiO or SnO2 materials. The excellent performance can be attributed to the synergistic effect between SnO2 and NiO. Our results demonstrate the potential applications of SnO2/NiO core-shell nanobelts in high-performance lithium-ion batteries. [Copyright &y& Elsevier]

Abstract: NiO nanowalls/graphene nanosheets (NiO/GNSs) nanocomposites are synthesized by a hydrothermal method, and their application as anodes of lithium-ion batteries has been investigated. NiO nanowalls were uniformly coated over the surface of graphene. NiO/GNSs nanocomposites exhibit extremely high cyclability and capacity. The reversible capacity is 844.9mAhg−1 at 0.1C rate (10h per half cycle) and fades merely 7.1% after 50 cycles. The present results indicate that NiO/GNS nanocomposites have potential applications in lithium-ion battery anodes. [Copyright &y& Elsevier]

Abstract: Co3O4/graphene nanocomposites are synthesized by a hydrothermal method, and their extremely high capacity and stability as the anode of lithium-ion battery is obtained. Co3O4 nanowires with the length of ~500nm and the diameter of ~50nm are uniformly coated on the surface of graphene nanosheets. The reversible capacity is 906.6mAhg−1 at 0.1C rate (10h per charging cycle) and fades merely 6.9% after 50 cycles. Such behaviors can be attributed to high electron and Li-ion conductivity, large surface area, good mechanical flexibility of graphene nanosheets and the synergetic effect between graphene and Co3O4 nanostructures. The present results indicate that Co3O4/graphene nanocomposites have potential applications in the anode of LIB. [Copyright &y& Elsevier]