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Hexagonally ordered mesoporous LiFePO4/C nanocomposites can be synthesised with LiFePO4 nanoparticles embedded in an interconnected carbon framework. Mesoporous LiFePO4/C nanocomposites exhibit superior electrochemical performance and ultra‐high specific power density, which makes this architecture suitable for high power applications such as HEVs and stationary energy storage for smart grids.

In this work, we have synthesized highly ordered mesoporous NiO materials by a nanocasting method using mesoporous silica KIT-6 as the hard templates. Mesoporous NiO particles were characterized by small angle X-ray diffraction (XRD), nitrogen adsorption/desorption, and transmission electron microscopy (TEM). The results demonstrated that the as-prepared mesoporous NiO had an ordered Ia3d symmetric mesostructure, with a high surface area of 96 m 2 /g. Mesoporous NiO materials were tested as an anode material for lithium ion batteries, exhibiting much lower activation energy (20.75 kJ mol À1 ) compared to the bulk NiO (45.02 kJ mol À1 ). We found that the mesoporous NiO electrode has higher lithium intercalation kinetics than its bulk counterpart. The specific capacity of mesoporous NiO after 50 cycles was maintained 680 mAh/g at 0.1 C, which was much higher than that of the commercial bulk NiO (188 mAh/g). Furthermore, at a high rate of 2C, the discharge capacity of mesoporous NiO was as high as 515 mAh/g, demonstrating the potential to be used for high power lithium ion batteries.

An in situ hydrothermal synthesis approach has been developed to prepare SnO 2 @graphene nanocomposites. The nanocomposites exhibited a high reversible sodium storage capacity of above 700 mA h g À1 and excellent cyclability for Na-ion batteries. In particular, they also demonstrated a good high rate capability for reversible sodium storage.Na-ion batteries are considered to be an alternative to Li-ion batteries owing to the natural abundance of sodium. 1 They have emerged as an attractive electrochemical power source for large-scale electrical energy storage (EES). [2][3][4][5] The Na ion has a larger ionic radius than that of the Li ion, making it more difficult to identify suitable electrode materials for Na-ion batteries. Electrode materials with an open framework are required for facile Na ion insertion/extraction. Following this strategy, many breakthroughs in cathode materials have been achieved, such as layered transition metal oxides, 6-9 threedimensional Na 0.44 MnO 2 with an S-shaped tunnel, 10,11 and Prussian blue with a new framework. 12 However, the development of suitable anode materials for Na-ion batteries remains a considerable challenge. It was found that hard carbon is a suitable anode material for Na-ion batteries because it has large interlayer distance and disordered structure. 13 However, Dahn et al. reported that the Na-intercalated hard carbon (Na x C) has high reactivity with the non-aqueous electrolyte, 14 raising new concerns about the stability of the electrolyte when used as a carbon based electrode. Alternative oxide anodes such as Na 2 Ti 3 O 7 15 and amorphous TiO 2 -nanotubes 16 have been investigated, but they all show less than 300 mA h g À1 capacities, which is far from meeting the demand of high energy storage. Transition metal oxides also did not achieve satisfactory performance, 17 although they have demonstrated excellent electrochemical properties in Li-ion batteries. Recently, it was found that anodes based on Na alloying reaction can dramatically improve the capacity of sodium storage. 18,19 It was reported that an SnSb-C nanocomposite achieved 544 mA h g À1 capacity, good rate capacity and cyclability for Na-ion storage, 18 and pure micrometric antimony can sustain a capacity close to 600 mA h g À1 at a high rate in Na-ion batteries. 20 SnO 2 can also react with Na based on a reversible Na alloying reaction and generate an Na-Sn alloy, which has potential as anode materials for Na-ion batteries. Based on the reaction 4SnO 2 + 31Na + + 31e À -Na 15 Sn 4 + 8Na 2 O, 18 SnO 2 can deliver a theoretical sodium storage capacity of 1378 mA h g À1 . However, large volume variation occurs during the charge-discharge process, inducing rapid capacity loss. Embedding SnO 2 in carbon matrices can effectively cushion the volume expansion of the SnO 2 electrode. Among various carbon matrices, graphene has several advantages such as superior conductivity, large surface areas, and excellent mechanical strength. Therefore, SnO 2 -graphene nanocomposites could be a high performance anod...

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