Sodium-ion batteries are an alternative to lithium-ion batteries for large-scale applications. However, low capacity and poor rate capability of existing anodes are the main bottlenecks to future developments. Here we report a uniform coating of antimony sulphide (stibnite) on graphene, fabricated by a solution-based synthesis technique, as the anode material for sodium-ion batteries. It gives a high capacity of 730 mAh g À 1 at 50 mA g À 1 , an excellent rate capability up to 6C and a good cycle performance. The promising performance is attributed to fast sodium ion diffusion from the small nanoparticles, and good electrical transport from the intimate contact between the active material and graphene, which also provides a template for anchoring the nanoparticles. We also demonstrate a battery with the stibnite-graphene composite that is free from sodium metal, having energy density up to 80 Wh kg À 1 . The energy density could exceed that of some lithium-ion batteries with further optimization.

We describe a method for conformal coating of reduced graphene oxide (rGO) by stibnite nanocrystallites. First, graphene oxide (GO) supported amorphous hydroperoxoantimonate was produced using the recently introduced hydrogen peroxide synthesis route. Sulfurization of the amorphous antimonate yielded supported antimony(V) oxide nanoparticles and sulfur, which were then converted by high temperature vacuum treatment to 15−20 nm rGO supported stibnite. The usefulness of the new material and synthesis approach are demonstrated by highly efficient and stable lithium battery anodes. Since both sulfur lithiation and antimony−lithium alloying are reversible, they both contribute to the charge capacity, which exceeded 720 mA h g −1 after 50 cycles at a current density of 250 mA g −1 . The very small crystallite size of the stibnite provides a minimum diffusion pathway and allows for excellent capacity retention at a high rate (>480 mA h g −1 at 2000 mA g −1 was observed). The nanoscale dimensions of the crystallites minimize lithiation-induced deformations and the associated capacity fading upon repeated charge−discharge cycles. The flexibility and conductivity of the rGO ensure minimal ohmic drop and prevent crack formation upon repeated cycles.

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 À1 charge capacity at 50 mA g À1 (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 À1 at 2000 mA g À1 .

The crystal structure of cesium hexahydroperoxostannate Cs(2)Sn(OOH)(6) is presented. The compound was characterized by single crystal and by powder X-ray diffraction, FTIR, (119)Sn MAS NMR, and TG-DTA. Cs(2)Sn(OOH)(6) crystallizes in the trigonal space group P3, a = 7.5575(4), c = 5.1050(6) A, V = 252.51(4) A(3), Z = 1, R(1) = 0.0120 (I > 2sigma(I)), wR(2) = 0.0293 (all data), and comprises cesium cations and slightly distorted octahedral [Sn(OOH)(6)](2-) anions lying on the threefold axis. The [Sn(OOH)(6)](2-) unit forms 12 interanion hydrogen bonds resulting in anionic chains spread along the c-axis. All six hydroperoxo ligands are crystallographically equivalent; O-O distances are 1.482(2), only slightly longer than the O-O distance in hydrogen peroxide. FTIR and (119)Sn MAS NMR reveal the similarity between all alkali hydroperoxostannates.

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A peroxogermanate thin film was deposited in high yield at room temperature on graphene oxide (GO) from peroxogermanate sols. The deposition of the peroxo-precursor onto GO and the transformations to amorphous GeO, crystalline tetragonal GeO, and then to cubic elemental germanium were followed by electron microscopy, XRD, and XPS. All of these transformations are influenced by the GO support. The initial deposition is explained in view of the sol composition and the presence of GO, and the different thermal transformations are explained by reactions with the graphene support acting as a reducing agent. As a test case, the evaluation of the different materials as lithium ion battery anodes was carried out revealing that the best performance is obtained by amorphous germanium oxide@GO with >1000 mAh g at 250 mA g (between 0 and 2.5 V vs Li/Li cathode), despite the fact that the material contained only 51 wt % germanium. This is the first demonstration of the peroxide route to produce peroxogermanate thin films and thereby supported germanium and germanium oxide coatings. The advantages of the process over alternative methodologies are discussed.