Search

A three-dimensional (3D) carbonaceous aerogel derived from biomass bacterial cellulose (BC) is introduced as a flexible framework for iron oxides in Li-ion batteries (LIBs). The 3D carbonized BC (CBC) with highly interconnected nanofibrous structure exhibits good electrical conductivity and mechanical stability. The amorphous Fe 2 O 3 is tightly coated on the nanofibers of CBC through a simple in situ thermal decomposition method. The obtained amorphous Fe 2 O 3 anode (denoted as A-Fe 2 O 3 @CBC) exhibits stable cycling performance and high rate capability when assembled into a half-cell, which is supposed to benefit from the well-dispersed Fe 2 O 3 nanoshells and the hierarchical pores in A-Fe 2 O 3 @CBC composite. The rational design of the nanostructure could improve the transportation of electrons/ions and effectively alleviate volume changes of Fe 2 O 3 during the electrochemical cycling. Meanwhile, the amorphous nature of the Fe 2 O 3 in anode provides an enhanced capacitive-like lithium storage and flexible structure of the active materials, resulting in much higher specific capacity and longer cycle life when compared with its crystalline counterpart. This work provides a promising approach to design and construct the flexible metal oxide anode materials based on 3D carbonaceous aerogel for high-performance LIBs. [ABSTRACT FROM AUTHOR]

Seeking high-capacity, high-rate, and durable anode materials for lithium-ion batteries (LIBs) has been a crucial aspect to promote the use of electric vehicles and other portable electronics. Here, a novel alloy-forming approach to convert amorphous Si (a-Si)-coated copper oxide (CuO) core-shell nanowires (NWs) into hollow and highly interconnected Si-Cu alloy (mixture) nanotubes is reported. Upon a simple H2 annealing, the CuO cores are reduced and diffused out to alloy with the a-Si shell, producing highly interconnected hollow Si-Cu alloy nanotubes, which can serve as high-capacity and self-conductive anode structures with robust mechanical support. A high specific capacity of 1010 mAh g−1 (or 780 mAh g−1) has been achieved after 1000 cycles at 3.4 A g−1 (or 20 A g−1), with a capacity retention rate of ≈84% (≈88%), without the use of any binder or conductive agent. Remarkably, they can survive an extremely fast charging rate at 70 A g−1 for 35 runs (corresponding to one full cycle in 30 s) and recover 88% capacity. This novel alloy-nanotube structure could represent an ideal candidate to fulfill the true potential of Si-loaded LIB applications. [ABSTRACT FROM AUTHOR]

Mesoporous silicon microspheres were fabricated via in situ magnesiothermic reduction of silicon oxide. Scanning and transmission electron microscopy images indicate that the diameter of the mesoporous silicon microspheres is approximately 500 nm. Mesopores with diameters ranging from 10 to 30 nm are homogeneously distributed in the silicon microspheres. The as-prepared mesoporous silicon microspheres show a reversible capacity of 3000 mAh g at 100 mA g discharge current density. After 60 cycles, the mesoporous silicon microspheres can still deliver a 1500 mAh g capacity at 1000 mA g discharge current density. The high reversible capacity, excellent cycling, and good rate capability of the fabricated material can be attributed to its mesoporous morphology and ultrafine particle size. [ABSTRACT FROM AUTHOR]

Network structured carbonized bacterial cellulose-supported Ru nanoparticles (CBC/Ru), which provide sufficient space for Li2O2 deposition without a significant volume effect and improve the transport of oxygen and electrons, were used as the binder-free oxygen electrode in a Li–O2 battery. The CBC/Ru exhibited high activities and good stability during discharge–recharge processes. [ABSTRACT FROM AUTHOR]

Two-dimensional Sn-based metal compounds (e.g. SnS, SnS 2 and SnO 2 ) are exceptionally attractive due to their excellent ion intercalation response and are suitable for use in energy storage devices (e.g. lithium-ion batteries and supercapacitors). However, the application of these dichalcogenides in Li-ion batteries is hindered by limitations in large-scale solution synthesis of SnS nanobelts. In this study, we developed a universal hydrothermal approach for the synthesis of SnS nanobelts and proposed an underlying mechanism for the formation reaction. When used as anode materials for lithium-ion batteries, SnS nanobelts maintain a discharge capacity of 889.9 mAhg −1 after 50 cycles at a current density of 0.1 A/g. The nanobelts also exhibit high electrochemical performance, high rate capacity, and high reversible capacity. These results demonstrate that SnS nanobelts are potential anode materials for high-performance energy storage applications. [ABSTRACT FROM AUTHOR]

Graphene-based nanocomposites have been widely investigated as promising anode materials because of the high specific capacity and good rate capability. However, effective distributing the nanomaterials into graphene conductive network still remains some challenges. In this study, the supercritical carbon dioxide (SC-CO 2 ) route as a good strategy is developed to prepare SnS 2 /reduced graphene oxide (RGO) nanocomposites, which integrates the complementary effect of ultrasmall SnS 2 nanopaticle and RGO nanosheet in the nanocompositions. The SnS 2 /RGO nanocomposite exhibits high initial discharge capacity of 1466.1 mA h g −1 (100 mA g −1 ), good capacity retention of about 492 mA h g −1 (100 mA g −1 ) after 70 cycles and good rate capacity as an anode material for lithium ion batteries. These results demonstrate that supercritical CO 2 (SC-CO 2 ) possess significant technological value to enhance the energy storage properties of other two-dimensional (2D) nanocomposites. [ABSTRACT FROM AUTHOR]

Two-dimensional transition-metal dichalcogenides, such as tungsten disulfide (WS 2 ), have been actively studied as suitable candidates for anode materials used in lithium ion batteries recently, due to their remarkable ion intercalation properties. However, the difficulties in the synthesis of phase-pure WS 2 , restacking between WS 2 nanosheets, low electronic conductivity and brittle nature of WS 2 severely limit its Li-ion batteries application. Here, we adopt a one-pot method for synthesizing of WS 2 /reduced Graphene Oxide (rGO) composite to improve the battery performance dramatically. The WS 2 /rGO anode shows a stable discharge capacity of 431.2 mAh/g, at a current density of 0.1 A/g after 100 cycles, while the capacity of bare WS 2 is only 65.5 mAh/g under the same condition. The added graphene oxide is reduced to rGO in reaction process and constitute stable composite with WS 2 , not only avoiding the restacking between WS 2 nanosheets and improving the conductive properties, but also promoting the reduction of WO 3 effectively. Our work may provide a possible route to avoid oxygen impurities in transition metal dichalcogenides. [ABSTRACT FROM AUTHOR]

Abstract: CuO nanoparticles are directly formed on graphene nanosheets through the in situ chemical decomposition of Cu(NO3)2·3H2O and are anchored tightly on the graphene surface. The lithiation-induced strain is naturally accommodated, owing to the constraint effect of the graphene matrix. Electrochemical characterization shows that CuO nanoparticles anchored on graphene sample exhibits a high capacity of about 660mAh/g at a discharge current density of 100mA/g and a good cycling ability. During the charge–discharge process, graphene nanosheets not only served as a three-dimensional conductive network for CuO nanoparticles, but also improve the detachment and agglomeration of CuO nanoparticles. This CuO/graphene nanocomposite displays superior Li-battery performance with large reversible capacity, excellent cyclic performance, and good rate capability. [Copyright &y& Elsevier]

Aqueous zinc-ion batteries (AZIBs), with the merits of high safety, environmental friendliness, abundant resources, and competitive energy density are recognized as a promising secondary battery technology and are anticipated to be a great alternative to organic lithium-ion batteries (LIBs). However, the commercial application of AZIBs is severely hindered by intractable issues, including high desolvation barrier, sluggish ion transport kinetics, growth of zinc dendrite, and side reactions. Nowadays, cellulosic materials are frequently employed in the fabrication of advanced AZIBs, because of the intrinsically excellent hydrophilicity, strong mechanical strength, sufficient active groups, and unexhaustible production. In this paper, we start from reviewing the success and dilemma of organic LIBs, followed by introducing the next-generation power source of AZIBs. After summarizing the features of cellulose with great potential in advanced AZIBs, we comprehensively and logically analyze the applications and superiorities of cellulosic materials in AZIBs electrodes, separators, electrolytes, and binders with an in-depth perspective. Finally, a clear outlook is delivered for future development of cellulose in AZIBs. Hopefully, this review can offer a smooth avenue for future direction of AZIBs by means of cellulosic material design and structure optimization. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Co3O4/graphene nanosheet (GNS) composites were synthesized via the in situ growth of mesoporous Co3O4 nanoparticles on graphene. The as-prepared Co3O4/GNS composites exhibited superior Li-ion battery performance and showed a large reversible capacity, excellent cycling, and good rate capability when used as an anode material in lithium ion batteries (LIBs). The uniform coating of Co3O4 around the graphene surface ensured tight electrical contact, resulting in a material with higher specific capacity and enhanced cycling performance compared with pure Co3O4 electrodes. The composites delivered a reversible capacity of 900mAhg−1 at a discharge current density of 100mAg−1 with good cycling ability. Moreover, the composites showed exceptional high-current charge–discharge performance, achieving 650mAhg−1 at a current density of 1000mAg−1. [Copyright &y& Elsevier]

Abstract: A MnO nanoparticle/graphene composite was prepared via in situ carbothermal reduction of Mn3O4 on the surface of graphene nanosheets. The formed MnO nanoparticles with diameters ranging from 20nm to 250nm integrated tightly with the graphene nanosheets. As anode material for lithium-ion batteries, the nanocomposite showed a high specific capacity of approximately 700mAhg−1 at 100mAg−1, excellent cyclic stability, and good rate capability. During the charge-discharge process, graphene nanosheets served as a three-dimensional conductive network for MnO nanoparticles. Furthermore, the detachment and agglomeration of MnO nanoparticles were effectively prevented due to the tight combination of MnO nanoparticles and graphene. [Copyright &y& Elsevier]