Nanocrystalline tin disulfide coating of reduced graphene oxide produced by the peroxostannate deposition route for sodium ion battery anodes† Petr V. Prikhodchenko, a Denis Y. W. Yu, * bcd Sudip K. Batabyal, c Vladimir Uvarov, e Jenny Gun, f Sergey Sladkevich,‡ f Alexey A. Mikhaylov, af Alexander G. Medvedev af and Ovadia Lev * ef A highly stable sodium ion battery anode was prepared by deposition of hydroperoxostannate on graphene oxide from hydrogen-peroxide-rich solution followed by sulfidization and 300  C heat treatment. The material was characterized by electron microscopy, powder X-ray diffraction and X-ray photoelectron spectroscopy which showed that the active material is mostly rhombohedral SnS 2 whose (001) planes were preferentially oriented in parallel to the graphene oxide sheets. The material exhibited >610 mA h g 1 charge capacity at 50 mA g 1 (with >99.6% charging efficiency) between 0 and 2 V vs. Na/Na + electrode, high cycling stability for over 150 cycles and very good rate performance, >320 mA h g 1 at 2000 mA g 1 . Introduction There is renewed interest in sodium ion batteries, NIBs, as an alternative for lithium ion batteries, LIBs, 1–3 due to the higher abundance of sodium on the earth's crust and its lower cost. 4 The half cell redox potential of sodium is higher than that of lithium which is a considerable drawback from the energy density perspective. Sodium poses an additional challenge due to its larger size compared to Li – it induces a larger volume change upon intercalation and it does not intercalate into graphitic anodes, though hard carbon was proposed more than a dozen years ago by Dahn et al. 5 Several oxides of Co, Sb, Fe, and Ti and suldes of Ti, Ta, Mo, Ni and Fe were proposed as host matrices for the intercalation of sodium, but, in most cases (except for antimony), the specic charge capacity of the oxides was less than 200 mA h g 1 and the reversibility was consider- ably inferior to lithium anodes. 6 A more successful route towards obtaining high capacity anodes is by exploiting the sodium alloying capability of tin, antimony, and, to some extent, also of germanium and lead. 2,7 Inspired by the success of Sony's Nexilion battery and other Sn composite LIB anodes, and by the fact that the Sn–Na 15 Sn 4 transformation involves a large theoretical capacity of 847 mA h per g Sn, tin-based nano- composites have been gaining scientic attention recently. Komaba et al. 8 used the tin powder electrode in the polyacrylate binder to deliver 500 mA h g 1 for approximately 20 cycles at 50 mA g 1 . Datta et al. 9 studied the performance of a ball milled nanocomposite of tin and graphite as an NIB anode and showed 400 mA h g 1 for 20 cycles at 50 mA g 1 . Xiao et al. 10 examined the SnSb–carbon composite that was prepared by mechanical milling of the three ingredients to show over 400 mA h g 1 aer 50 cycles at 100 mA g 1 . However, it is clear that although the alloying route is currently most promising, higher capacity, better rate performance, and, above all, better cycling stability are due before NIBs can compete with secondary lead acid batteries let alone with LIBs. One of the methods to increase LIB anode capacities is to use tin sulde coated graphene oxide. Conversion of tin sulde to Li 2 S and Li 4.4 Sn can generate a theoretical charge capacity of 1230 mA h per g SnS 2 . Indeed several authors pursued successfully this route for LIB production, oen using graphe- nes to decrease the electrode resistance and to buffer volume expansion during lithiation. 11–16 However, to date there is only a single report of the NIB anode incorporating tin sulde. Wu et al. 17 demonstrated that a composite made by high energy mechanical milling of Sn, SnS and carbon gave a reversible a Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii prosp. 31, Moscow 119991, Russia b School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China. E-mail: denisyu@cityu.edu.hk c Energy Research Institute @ NTU, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore d TUM CREATE, #10-02 Create Tower, 1 CREATE Way, Singapore 138602, Singapore e The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel f The Casali Center of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel. E-mail: ovadia@vms.huji.ac.il; Fax: +972 (0)26586155; Tel: +972 (0)26584191 † Electronic supplementary information (ESI) available. See DOI: 10.1039/c3ta15248k ‡ Currently at Geological Survey of Israel, 30 Malkhe Israel St., Jerusalem 95501, Israel Cite this: J. Mater. Chem. A, 2014, 2, 8431 Received 17th December 2013 Accepted 12th March 2014 DOI: 10.1039/c3ta15248k www.rsc.org/MaterialsA This journal is © The Royal Society of Chemistry 2014 J. Mater. Chem. A, 2014, 2, 8431–8437 | 8431 Journal of Materials Chemistry A PAPER Published on 29 April 2014. Downloaded by Hebrew University of Jerusalem on 18/05/2014 08:16:32. View Article Online View Journal | View Issue