Elsevier

Materials Letters

Volume 180, 1 October 2016, Pages 243-246
Materials Letters

Li-electroactivity of thermally-reduced V2O3 nanoparticles

https://doi.org/10.1016/j.matlet.2016.05.138Get rights and content

Highlights

  • V2O3 nanoparticles are prepared via the thermal reduction of VO2 nanoparticles.

  • V2O3 nanoparticles exhibit an excellent cycling stability over 400 cycles.

  • V2O3 nanoparticles maintain their initial structure after the cycling test.

Abstract

In this work, vanandium(III) oxide nanoparticles (V2O3 NPs) were prepared via the heat treatment of hydrothermally prepared vananium(IV) oxide (VO2) NPs in a reducing atmosphere. The V2O3 NPs had a spherical shape with a size of less than 50 nm as the initial VO2 NPs. These V2O3 NPs without any conductive additives showed both long-term structural and electrochemical cycling stability (~142 mA h g−1 of reversible capacity up to 400 cycles) for Li ion battery anodes.

Introduction

Vanadium oxides (VOx) have attracted considerable interest as energy storage materials in lithium-ion battery (LIB) because of their special structural characteristics [1]. VOx exist in different compositions, such as V2O5, V3O7, VO2, and V2O3, depending on the oxidation states of the vanadium ion from 5+ to 2+ [2]. Among them, V2O5 and VO2 are potential electrode materials in LIBs [1]. However, unlike other VOx, there are few reports of vanandium(III) oxide (V2O3) as an electrode material in LIBs owing to its low valence state and meta-stability, resulting in low cyclability and poor rate performance. In addition, there are limited reports of the synthesis of V2O3-based nano-sized materials and their electrochemical applications, because it is difficult to synthesize phase-pure V2O3 nanomaterials owing to their intrinsic sensitivity [3]. Recently, however, the electrochemical properties of V2O3 nanomaterials have attracted some attention for aqueous and non-aqueous electrolytes [3], [4], [5], [6], [7], [8].

This letter reports V2O3 NPs that exhibit stable cycling performance. For that, V2O3 NPs were prepared via the thermal reduction of vananium(IV) oxide nanoparticles (VO2 NPs). The VO2 NPs were synthesized using a sol-gel-assisted hydrothermal reaction [9], and then heat treated in a reducing atmosphere to produce the V2O3 NPs. The electrochemical properties of these prepared V2O3 NPs were investigated, and the microstructural properties of the V2O3 NPs after multiple cycling were also carefully characterized.

Section snippets

Experimental sections

0.9 g V2O5 (99%, Sigma-Aldrich) powder was dissolved in a solution of 25 ml deionized water and 5 ml hydrogen peroxide (H2O2; 30 wt%, OCI Company) under continuous stirring to produce the gel. After aging for 24 h, hydrazine monohydrate (N2H4·H2O; 98%, Sigma-Aldrich) was added with vigorous mixing, resulting in the formation of a stiff gel. This resulting gel was transferred to a 75 ml Teflon-lined stainless steel autoclave, and heated the electronic oven as the reactant temperature became ~220 °C for

Results and discussion

Fig. 1(a) presents XRD patterns of the phase transformation from the as-prepared VO2 NPs to V2O3 NPs via the thermal reduction process. The XRD peaks of the hydrothermally synthesized samples (bottom graph in Fig. 1(a)) were assigned to the M-phase VO2 from the reference data (JCPDS no. 43-1051; monoclinic unit cell with the space group P21/C). When the VO2 NPs were heat treated under 300 °C (middle graph in Fig. 1(a)), there was no phase change, but a phase transformation occurred between 300

Conclusions

V2O3 NPs were prepared by the thermal reduction of VO2 NPs synthesized by a hydrothermal method. The VO2 NPs were reduced successfully to phase-pure V2O3 NPs in a reducing atmosphere near 400 °C. The particle morphology and size maintained at their initial states during the thermal reduction. These V2O3 NPs exhibited outstanding cycling stability up to 400 cycles with a discharge capacity of 142 mA h g−1 despite the absence of conductive additives. Therefore, the V2O3 NPs could have a potential use

Acknowledgements

This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Ministry of Science, ICT, and Future Planning (No. 2016R1A2B2012728).

References (12)

  • Y. Zhang et al.

    Mater. Lett.

    (2014)
  • S. Ji et al.

    Sol. Energy Mater. Sol. Cells

    (2011)
  • J. Mendialdua et al.

    J. Electron spectros. Relat. Phenom.

    (1995)
  • H.J. Song et al.

    Electro. Acta

    (2015)
  • C. Wu et al.

    Energy Env. Sci.

    (2010)
  • H. Liu et al.

    J. Mater. Chem.

    (2009)
There are more references available in the full text version of this article.

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