In this work, a simple, high-yield biomineralization process is reported for cobalt oxide nanostructures using Gram-positive bacteria, Bacillus subtilis , as the soft templates. Rod-type cobalt oxide is prepared at room temperature through an electrostatic interaction between the functional surface structures of the bacteria and the cobalt ions in an aqueous solution. Additionally, porous Co₃O₄ hollow rods are formed through a subsequent heat treatment at 300 °C. These rods have a high surface area and exhibited an excellent electrochemical performance for rechargeable Li-ion batteries. This facile, inexpensive, and environmentally benign synthesis for transition metal oxides with unique nanostructures can be used for several practical applications, such as batteries, catalysts, sensors, and supercapacitors.

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We herein present the synthesis of germanium (Ge) nanowires on Au-catalyzed low-temperature substrates using a simple thermal Ge/Sn co-evaporation method. Incorporation of a low-melting point metal (Sn) enables the efficient delivery of Ge vapor to the substrate, even at a source temperature below 600 °C. The as-synthesized nanowires were found to be a core/shell heterostructure, exhibiting a uniform single crystalline Ge sheathed within a thin amorphous germanium suboxide (GeO(x)) layer. Furthermore, these high-density Ge nanowires grown directly on metal current collectors can offer good electrical connection and easy strain relaxation due to huge volume expansion during Li ion insertion/extraction. Therefore, the self-supported Ge nanowire electrodes provided excellent large capacity with little fading upon cycling (a capacity of ∼900 mA h g(-1) at 1C rate).

Phase-pure urchin-like rutile TiO 2 (U-TiO 2 ) submicron (<1 mm) spheres composed of numerous single-crystalline nanorods are successfully synthesized using a surfactant-free wet-chemical route. In addition, a reliable mechanism for the formation of U-TiO 2 , different from the well-known ''growth-then-assembly'' mode, is suggested. To provide a highly electron-conducting network, the U-TiO 2 submicron spheres are nanopainted with a conductive amorphous carbon layer. As anodes for Li-ion batteries, the carbon-coated U-TiO 2 submicron sphere electrodes show enhanced cycling performance, maintaining a reversible capacity of 165.7 mA h g À1 after 100 cycles at a rate of 0.2 C; this is attributed to the provision of an efficient electron-transport path by the conductive carbon.

Monodispersed core/shell spinel ferrite/carbon nanoparticles are formed by thermolysis of metal (Fe3+, Co2+) oleates followed by carbon coating. The phase and morphology of nanoparticles are characterized by x-ray diffraction and transmission electron microscopy. Pure Fe3O4 and CoFe2O4 nanoparticles are initially prepared through thermal decomposition of metal–oleate precursors at 310 degrees C and they are found to exhibit poor electrochemical performance because of the easy aggregation of nanoparticles and the resulting increase in the interparticle contact resistance. In contrast, uniform carbon coating of Fe3O4 and CoFe2O4 nanoparticles by low-temperature (180 degrees C) decomposition of malic acid allowed each nanoparticle to be electrically wired to a current collector through a conducting percolative path. Core/shell Fe3O4/C and CoFe2O4/C nanocomposite electrodes show a high specific capacity that can exceed 700 mAh g(-1) after 200 cycles, along with enhanced cycling stability.