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mA G (ma + g)

Distribution by Scientific Domains

Polymers and Materials Science	75%

Selected Abstracts

Topotactic Conversion Route to Mesoporous Quasi-Single-Crystalline Co3O4 Nanobelts with Optimizable Electrochemical Performance

ADVANCED FUNCTIONAL MATERIALS, Issue 4 2010
Li Tian
Abstract The growth of mesoporous quasi-single-crystalline Co3O4 nanobelts by topotactic chemical transformation from , -Co(OH)2 nanobelts is realized. During the topotactic transformation process, the primary , -Co(OH)2 nanobelt frameworks can be preserved. The phases, crystal structures, morphologies, and growth behavior of both the precursory and resultant products are characterized by powder X-ray diffraction (XRD), electron microscopy,scanning electron (SEM) and transmission electron (TEM) microscopy, and selected area electron diffraction (SAED). Detailed investigation of the formation mechanism of the porous Co3O4 nanobelts indicates topotactic nucleation and oriented growth of textured spinel Co3O4 nanowalls (nanoparticles) inside the nanobelts. Co3O4 nanocrystals prefer [0001] epitaxial growth direction of hexagonal , -Co(OH)2 nanobelts due to the structural matching of [0001] , -Co(OH)2//[111] Co3O4. The surface-areas and pore sizes of the spinel Co3O4 products can be tuned through heat treatment of , -Co(OH)2 precursors at different temperatures. The galvanostatic cycling measurement of the Co3O4 products indicates that their charge,discharge performance can be optimized. In the voltage range of 0.0,3.0,V versus Li+/Li at 40,mA g,1, reversible capacities of a sample consisting of mesoporous quasi-single-crystalline Co3O4 nanobelts can reach up to 1400,mA h g,1, much larger than the theoretical capacity of bulk Co3O4 (892,mA h g,1). [source]

Nest-like Silicon Nanospheres for High-Capacity Lithium Storage,

ADVANCED MATERIALS, Issue 22 2007
H. Ma
Nest-like Si nanospheres and their highly reversible lithium storage (3952 mAh g,1 at 100 mA g,1) and excellent high-rate capability (3052 mAh g,1 at 2000 mA g,1) are reported (see figure). This result suggests that the as-prepared nest-like Si nanospheres are promising candidates as the anode materials of rechargeable Li-ion batteries. [source]

Preparation of tin nanocomposite as anode material by molten salts method and its application in lithium ion batteries

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 11 2009
Mohd Faiz Hassan
Abstract A nanocomposite material (SnO2Co3O4) has been synthesized as an anode material for lithium-ion batteries by the molten salt method. Characterization by X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed that the composite has a small particle size. The electrochemical performance was examined, including the charge,discharge and cycling properties. The experimental results showed that the sample containing the highest amount of Co3O4 compound exhibited a specific capacity of 355,mAh g,1 after 40 cycles, with cycling at 70,mA g,1 (35.2% higher than for the sample containing a lower amount of Co3O4). It seems that increasing the amount of Co3O4 can give good capacity retention and high specific capacity. [source]