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Given the abundance of sodium resources, sodium-ion batteries (SIBs) have been considered as one of the candidates for storing energy on a large scale. However, the slower sodium ion transport in the electrode limits its use. Here, we report a binder free Zn2GeO4-graphene Ni foam integrated anode for Na ion storage. The obtained integrated anode was supported by nickel foam without binder, the Zn2GeO4 exhibits nanotube structure, and the graphene was coating on the Zn2GeO4. The Zn2GeO4 nanorods are able to coalesce with each other to form porous structures. The binder free Zn2GeO4-graphene Ni foam integrated anode electrode delivered a discharge capacity of 427.7 mAh g−1 at 0.1 A g−1 after 200 cycles. And at a high current density of 2 A g−1 a favorable rate capacity of 391.4 mAh g−1 could be achieved, twice that of the Zn2GeO4-graphene powder electrode. The outstanding electrochemical performance can be attributed to the synergistic effect between in situ grown Zn2GeO4 nanorods and graphene sheets, which enhanced the conductivity and stabilized the electrode structure during the cycling process, as well as the improved electrochemical reaction kinetics due to in-situ growth. This work sheds light on the design of Ge-based ternary oxide anodes and provides a promising anode for high performance SIBs. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.comnet.2006.08.015 Byline: Caixia Chi, Ruibing Hao Keywords: Feature interaction testing; Finite state machine; Dual graph; Euler tour; Chinese postman tour Abstract: This paper proposes two techniques to generate test sequences to check the conformance of an implementation of a feature-rich communication system to its specification, as well as to detect the interactions between the features of the system. Concepts color span and feasible combination of features are introduced to measure the extent and possibility of the interactions between different features. Several algorithms are proposed to produce an approximate minimum-cost and minimum color span tour of the transition graph of a finite-state machine. Test generation using the proposed algorithms for the SIP-based Internet telephony end system and for the Link Management Protocol is reported. Author Affiliation: Bell Labs Research China, Lucent Technologies, Beijing 100080, China Article Note: (miscellaneous) Responsible Editor: H. Rudin

In this work, a novel pyrrolic nitrogen-doped carbon sandwiched monolayer MoS2 hybrid was prepared. This sandwiched hybrid vertically anchors on graphene oxide as anode materials for sodium-ion batteries. Such electrode was fabricated by facile ionic liquid-assisted reflux and annealing methods. Owing to rational structure and enhancement from pyrrolic nitrogen dopant, this unique MoS2/C-graphene hybrid exhibits reversible specific capacity of 486 mAh g−1 after 1000 cycles with a low average fading capacity of 0.15 mAh g−1 (fading cyclic rate of ca. 0.03% per cycle). A capacity of 330 mAh g−1 is remained at the current densities of 10.0 A g−1. The proposed strategy provides a convenient way to create new pyrrolic nitrogen-doped hybrids for energy field and other related applications. [ABSTRACT FROM AUTHOR]

Heterogeneous interfaces interaction and multiscale nanostructures in two-dimensional (2D) materials hybrids are critically significant for realizing rate capability and long-life cycling performance. However, to strike a balance between minimizing the carbon content and maximizing the heterogeneous interfaces remains a critical challenge in nanoarchitectures for hybrid few-layers MoS2 with various carbonaceous materials. Here we present the ordered macroporous few-layered MoS2/C hybrid nanoarchitectures via a facile scalable in situ hybridization and spatial confinement strategies. Such hybrid strategies can maximize the MoS2 loading and restriction of MoS2 to a ultrasmall reaction. The optimized as-prepared hierarchical MoS2/C hybrids exhibit an initial capacity up to 631.2 mAh g−1 with a high first columbic efficiency of 81.16% for sodium-ion batteries (BILs) at 200 mA g−1. And, the electrodes display a high reversible capacity of 330.4 mAh g−1 with a long cycle life, superior cycling stability and excellent high-rate performance demonstrated rational designed hybrid architecture using as the electrodes in SIBs. This strategy could be proven to be an effective method for stabilizing the cyclability and improving in rechargeable rate performance for SIBs. [ABSTRACT FROM AUTHOR]

Achieving appropriate cycling stability for metal sulfides used as anodes in Li-ion batteries remains highly challenging because of structural collapse or low conductivity. Herein, a novel composite was designed as an anode material for Li-ion batteries. This unique architecture has the advantages of a large interface area, numerous channels for Li+ and electron transport, and a porous structure that facilitates electrolyte infiltration and buffers the volume expansion. As expected, this composite exhibits good cycling stability, high reversible capacity, and high rate capability, delivering a high discharge capacity of 1511.6 mA h g−1 and a high first columbic efficiency of 83.27%. The reversible capacities of graphitic-carbon network material (GCNM) electrodes are 1112 mA h g−1 at a current density of 0.1 A g−1 after 100 cycles, and they show superior rate capabilities. This GCNM composite demonstrates great potential for applications in power sources for flexible and lightweight electronic devices. [ABSTRACT FROM AUTHOR]

Vanadium oxide (V2O5), as a potential positive electrode for sodium ion batteries (SIBs), has attracted considerable attention from researchers. Herein, amorphous and crystalline V2O5 cathodes on a graphite paper without a binder and conductive additives have been synthesized via facile anodic electrochemical deposition following different heat treatments. Both the amorphous V2O5 (a-V2O5) cathode and crystalline V2O5 (c-V2O5) cathode show good rate cycling performance and long cycling life. After five rate cycles, the reversible capacities of both the cathodes were almost unchanged at different current densities from 40 to 5120 mA g−1. Long cycling tests with 10 000 cycles were carried out and the two cathodes exhibit excellent cycling stability. The c-V2O5 cathode retains a high specific capacity of 54 mA h g−1 after 10 000 cycles at 2560 mA g−1 and can be charged within 80 s. Interestingly, the a-V2O5 cathode possesses higher reversible capacities than the c-V2O5 cathode at low current densities, whereas it is inversed at high current densities. The c-V2O5 cathode shows faster capacity recovery from 5120 to 40 mA g−1 than the a-V2O5 cathode. When discharged at 80 mA g−1 (long discharge time of 140 min) and charged at 640 mA g−1 (short charge time of 17 min), the a-V2O5 cathode shows a higher discharge capacity than its c-V2O5 counterpart. The different electrochemical performance of a-V2O5 and c-V2O5 cathodes during various electrochemical processes can provide a rational selection of amorphous or crystalline V2O5 cathode materials for SIBs in their practical applications to meet the variable requirements. [ABSTRACT FROM AUTHOR]