Carbonaceous materials with high specific energy capacity are prime candidates for applications in rechargeable lithium batteries. The authors report the synthesis and characterization of ordered mesoporous carbon (CMK‐3), synthesized using ordered silica as a template, with high reversible specific capacity and good charge–discharge cycle characteristics. The performance of CMK‐3 is compared with that of carbon nanotubes, and its superiority is suggested to be related to the three‐dimensional ordered structure of CMK‐3.

Lithium-based storage devices with both high power and high energy densities are necessary for electric devices, especially for electric vehicles (EV) and other mobile or portable electric devices.[1] Herein we introduce a new concept to design a novel electrode material having a self-ordered, crystalline-glass, mesoporous nanocomposite (CGMN) structure for such industrial needs. The 5-nm frameworks of the CGMN are assembled in a compact arrangement from electrode-active nanocrystals with a small quantity of glass phase. The 4-nm uniform mesochannels of the CGMN can be filled with electrolyte solution during use to provide electrolyte and lithium-ion pathways throughout the material. In addition, the high surface area of the CGMN reduces the effective specific current density, and the three-dimensional glass network in the framework of the CGMN is able to incorporate a high content of electronic conductive oxides above the percolation-threshold value to form an electronic path, and to add lithium ions as a network modifier during the first insertion process to form an ionic path. The experimental results show that the specific capacities (energy density) at high current densities (power density) can be improved several hundred fold when the CGMN replaces TiO 2 powder as the electrode of a lithium-based storage device.An electric vehicle (EV) powered by a rechargeable battery is an ideal solution to reduce environmental pollution as it is a clean energy source. However, the power densities of rechargeable batteries are still too low to support such industrial needs, even though their energy densities are high. The development of such an energy-storage device with both high power and high energy densities has been widely studied.[1] There are two typical approaches in this field: one is to increase the energy density of the capacitor, which is often studied by measurement of the electrical double-layer capacity (EDLC), and the other is to improve the specific capacity of the rechargeable battery by a rapid chargedischarge process, especially for lithium-based rechargeable batteries. Recently, a great deal of effort has been spent on improving the energy density of the EDLC by increasing the effective surface area of carbon-based materials, [2] although the resulting densities are still too low. In the second approach there are four main problems that have to be solved: [3,4] a) the particle size needs to be decreased to reduce the required diffusion length in the active materials; b) the effective specific current density needs to be reduced in the rapid charge-discharge process; c) a high cycle performance needs to be achieved even during the rapid charge-discharge process; and d) the electronic conductivity of the electrode materials needs to be increased.The diffusion of lithium ions is very complex because the nature of the electrolyte phase, the solid-liquid interface, the tortuosity, and the size of the nanoparticles have to be considered.[5] Herein we only consider the the overall process by assuming that th...

A sonochemical method has been successfully used in order to incorporate MnO2 nanoparticles inside the pore channels of CMK‐3 ordered mesoporous carbon. Modification of the intrachannel surfaces of CMK‐3 to make them hydrophilic enables KMnO4 to readily penetrate the pore channels. At the same time, the modification changes the surface reactivity, enabling the formation of MnO2 nanoparticles inside the pores of CMK‐3 by the sonochemical reduction of metal ions. The resultant structures were characterized by X‐ray diffraction (XRD), nitrogen adsorption, and transmission electron microscopy (TEM). CMK‐3 with 20 wt.‐% loading of MnO2 inside CMK‐3 delivered an improved discharge performance of 223 mA h g–1 at a relatively high rate of 1 A g–1. Almost no decrease in specific capacity is observed for the second cycle, and a discharge capacity of more than 165 mA h g–1 is retained after 100 cycles. This is attributed to the nanometer‐sized MnO2 formed inside CMK‐3 and the high surface area of the mesopores (3.1 nm) in which the MnO2 nanoparticles are formed.

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V 2 O 5 /carbon composites were prepared from a homogeneous suspension in which vanadium pentoxide sol and acetylene black powder were mixed with acetone acting as a surfactant. The composite was loaded on indium-tin oxide ͑ITO͒-coated glass, and then the magnesium intercalation property and the high-rate charge-discharge performance were evaluated in an electrolyte of Mg(ClO 4 ) 2 /acetonitrile at room temperature. In cyclic voltammetry, two main peaks of a reversible redox reaction were observed. It was determined that 1.84 mol of Mg per mol of V 2 O 5 were inserted in the first cycle at a relatively slow sweep rate of 0.1 mV s Ϫ1 , which corresponds to a specific capacity of 540 mAh (g-V 2 O 5 ) Ϫ1 . Galvanostatic charge-discharge tests at various current densities showed a high capacity of about 600 mAh (g-V 2 O 5 ) Ϫ1 at a current density of 1.0 A (g-V 2 O 5 ) Ϫ1 , and about 300 mAh (g-V 2 O 5 ) Ϫ1 was maintained even at 20 A (g-V 2 O 5 ) Ϫ1 .