Search

ZnMn2O4 electrode materials were prepared by directly roasting mixed liquid with sucrose as the soft template. The influences of the amounts of sucrose on the structure, morphology and lithium storage properties of the synthesized ZnMn2O4 electrode materials were studied by XRI). FESEM, and electrochemical performance tests. When the molar ratio of Zn2+ to sucrose in the raw materials was 1:1.5. the prepared ZnMn2O4 sample showed a mixed morphology of irregular particles and nano-sheets. and exhibited the best lithium storage performance. The reversible capacity could reach 575 mAh/g after 200 cycles at 0.5 A/g current density. E-ven at the high current density of 5 A/g. it still delivered a reversible capacity of 295 mAh/g. The electrochemical reaction kinetic analysis showed that the ZMO-1.5 electrode had the lowest electrochemical reaction resistance and the highest lithium ion diffusion coefficient. This study was expected to provide guidance and theoretical reference for the facile and low-cost preparation of high performance ZnMn2O4 electrode materials. [ABSTRACT FROM AUTHOR]

A novel type of porous TiO 2 nanobelts anchored with Sn 3 O 4 nanosheets (TiO 2 nanobelts @Sn 3 O 4 nanosheets) core-shell composites were developed via two-step hydrothermal methods. The structure, morphology, formation mechanism and electrochemical performance of the porous TiO 2 nanobelts coated with mixed transition-metal oxides Sn 3 O 4 nanosheets core-shell composites were researched. The results illustrated that the Sn 3 O 4 nanosheets were uniformly anchored on the surface of the porous TiO 2 nanobelts, which were almost perpendicular to the porous TiO 2 nanobelts. The composites as anode materials exhibited more remarkable electrochemical performances than the Sn 3 O 4 nanosheet and the porous TiO 2 nanobelts, in terms of the cycling performance and rate capability. The initial discharge capacity was 1513.7 mAh/g and the reversible capacity was 659 mAh/g after 50 cycles. This study perhaps inspired the designing of other transition metal oxide-based anode materials with desirable electrochemical performance for applications of lithium ion batteries. [ABSTRACT FROM AUTHOR]

Novel hierarchical flower-like Sn 3 O 4 assembled by thin Sn 3 O 4 nanosheets , as a kind of mixed-valence tin oxide, decorated on two-dimensional graphene nanosheets has been synthesized via a hydrothermal route and a step solution deoxidization technique. More importantly, as the anode materials for lithium ion batteries, the flower-like Sn 3 O 4 /graphene composite has not been investigated in detail. Noticeably, the nanosheets stemming from flower-like Sn 3 O 4 and graphene have been linked together to form a specials three dimensional structure, possessing high active surface area and large enough inner spaces, which is benefit to the diffusion of liquid electrolyte into the electrode materials. In addition, the special structure could provide sufficient free volume to buffer the volume expansion appeared in the process of discharging and charging. The as-prepared flowers-like Sn 3 O 4 /graphene displayed excellent electrochemical performance with high capacity and good cycling stability as anode materials for lithium ion batteries. The discharge capacity is 1727 mAh/g in the first cycle at the current density of 60 mA/g. The obtained reversible capacity is 631mAh/g with a coulomb efficiency of 97.04% after 50 cycles. With its better electrochemical properties, the as-prepared flowers-like Sn 3 O 4 /graphene has the potential to be the next generation materials as an environmentally benign, abundant, cheap anode materials for lithium ion batteries. [ABSTRACT FROM AUTHOR]

Transition metal oxides are said to have the ability to enhance the gravimetric capacity of lithium-ion batteries by two or three times that of current state-of-the-art graphite anodes. Recent reports have demonstrated that the combined utilization of structural architecture and surface modification is an attractive strategy to improve lithium storage capability. In this study, novel CuO-ZnO@Al 2 O 3 submicroflakes were prepared by magnetron sputtering deposition of Cu-Zn alloy films on a removable sacrificial substrate, followed by a facile thermal oxidation treatment and Al 2 O 3 coating procedure by particle atomic layer deposition. They combine the advantages of CuO-ZnO submicroflakes, such as high lithium storage capability and fast lithium ion transportation, and Al 2 O 3 nano-coating with effective protection of the electrode interface during cycling. When utilized as anode materials for LIBs, the CuO-ZnO@Al 2 O 3 submicroflakes exhibit superior specific capacity, enhanced cycling stability, and outstanding rate capability compared with pristine CuO-ZnO submicroflakes, commercial CuO and ZnO powders. The CuO-ZnO@Al 2 O 3 submicroflakes electrodes deliver a high reversible capacity of 814 mAh g−1 at a current density of 50 mA g−1, and still maintain a moderate capacity of 447 mAh g−1 at a high current density of 1000 mA g−1. Pairing with a commercial LiFePO 4 cathode, full cell shows high capacity retention and stable cycling performance, suggesting the feasibility of the CuO-ZnO@Al 2 O 3 submicroflakes in practical energy storage applications. In addition, our findings also provide a clear proof-of-concept of the surface coating technique, which might be applied widely to other materials and devices where nano-coating produces desirable properties. [Display omitted] • CuO-ZnO submicroflakes with Al 2 O 3 nano-coatings are fabricated for lithium-ion batteries. • The unique structural features endow fast ion transportation kinetics for charge storage. • The anodes possess high reversible capacity and remarkable rate capability. • The anodes exhibit long lifetime and stable cyclability in full cell measurements. [ABSTRACT FROM AUTHOR]

Novel a - MoO 3 nanorods coated with SnS 2 nanosheets core-shell nanorod composite has been synthesized via two hydrothermal routes. More importantly, as the anode materials for lithium ion batteries, the MoO 3 @SnS 2 core-shell nanorod composite has not been investigated in detail. The one-dimensional core-shell nanorod composite has high surface area, which could offer larger contact area for material and electrolyte. In addition, there are large enough inner spaces between the SnS 2 nanosheets, which provides an efficient transport of electrons and ions. In addition, the core-shell nanostructure could accommodate the volume changes caused by the charge/discharge reaction and could avoid the agglomerations and pulverization of anode materials.As anode materials for LIBs, the as-prepared MoO 3 @SnS 2 core-shell nanorod composite displayed 1663.2mAh/g discharge capacity in the first cycle at the current of 60mA/g. After 100 cycles, the remained capacity is 568.2mAh/g, which is both higher than that of a-MoO 3 and SnS 2 . Considering the excellent electrochemical performance with high capacity and good cycling stability, the as-prepared the MoO 3 @SnS 2 core-shell nanorod composite has the potential to be the next generation anode materials for lithium ion batteries. [ABSTRACT FROM AUTHOR]