Zn 2 SnO 4 coated reduced graphene oxide nanoribbons with enhanced electrochemical performance for lithium-ion batteries
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Graphene nanoribbons as a quasi-one-dimensional form of graphene has attracted intensive attention in energy related devices. Upon oxidation and cutting of multiwall carbon nanotubes (MWCNTs), highly dispersive graphene oxide nanoribbons (GONRs) were obtained, on which Zn21 and Sn41 can be homogenously deposited. The reduced graphene oxide nanoribbons (rGONRs)/Zn2SnO4 composite with a homogeneous distribution of nanoparticles on the nanoribbons have been prepared through facile in situ chemical co-reduction process. It is worth noting that the size of Zn2SnO4 particles tightly dispersed on rGONRs is about 15 nm. Benefit from the introduction of rGONRs, the specific surface area and electrode conductivity of rGONRs/Zn2SnO4 can both be effectively enhanced. The as-prepared rGONRs/Zn2SnO4 as anode material for lithium-ion batteries displays desirable electrochemical performance (727.2 mA h/g after 50 cycles at the current density of 100 mA/g), which is mainly attributed to the uniformly distributed Zn2SnO4 nanoparticles and the immobilizing and conducting effects of rGONRs.
I. INTRODUCTION
Graphene nanoribbons (GNRs), a quasi-onedimensional form of graphene, elegantly combine the structure and properties of carbon nanotubes and graphene sheets.1–3 Owing to their tunable electrical properties, high carbon aspect ratio, and high surface area, GNRs has attracted intensive attention from researchers in energy related devices.4–7 Recently, GNRs/metal oxide composites [GNRs/SnO2,4 GNRs/Fe2O3,8 GNRs/V2O5 (Ref. 9)] as electrode materials for lithium-ion batteries have been prepared and exhibited desirable capacities and rate performances. The GNRs in above-mentioned composites were prepared through the splitting of multiwalled carbon nanotubes (MWCNTs) utilizing intercalation of Na/K alloy. Nevertheless, it is worth noting that the experiment usually required time-consuming synthetic procedures (3–5 days) and rigorous condition. Therefore, it is highly desirable to develop a simple route for the synthesis of GNRs-based composite. Up to date, graphene oxide nanoribbons (GONRs) could be obtained via the oxidation of MWCNTs, and then reduced graphene oxide nanoribbons (rGONRs) could be got through further reductive treatment.10,11 Bhardwaj et al. reported that as-prepared GNRs (GONRs or rGONRs) delivered better electrochemical properties than MWCNTs or mesocarbon microbead (MCMB).12 Contributing Editor: Chongmin Xiao a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2016.431
Moreover, GONRs could be charged negatively in aqueous solution due to abundant of expoxy, hydroxyl, and carboxyl groups on basal planes and edges of GONRs,10,11 which is similar to graphene oxide (GO) produced by Hummers’ method.13,14 Hence, GONRs also can be served as excellent substrate to host metal oxide. The negatively charged GONRs and the positively charged metal ions can be favorably bond with each other via electrostatic interactions, which plays an important role in determining the uniform attachment of the
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