Carbon-Encapsulated Metal Oxide Hollow Nanoparticles and Metal Oxide Hollow Nanoparticles: A General Synthesis Strategy and Its Application to Lithium-Ion Batteries

Abstract

A novel and general strategy for the synthesis of carbon-encapsulated metal oxide hollow nanoparticles (HNPs) and pure metal oxide HNPs was developed from carbon-encapsulated metal nanoparticles by controlled oxidation in the air. The materials were characterized by transmission electron microscopy, scanning electron microscopy, and X-ray diffraction measurements. It was found that the morphologies and compositions of HNPs were easily tailored through adjustment of the oxidation conditions. When used as the anode materials for lithium-ion batteries, carbon-encapsulated α-Fe2O3 HNPs exhibit excellent cycling performance and a higher reversible capacity of about 700 mA h g−1 after the 60th cycle and possess great potential application in lithium-ion batteries.

Synthesis and Characterization of Chromium Oxide Nanoparticles

“…Transition metal oxide NPs have many applications as catalyst [1][2][3][4][5] , sensors [6][7][8][9] , superconductors [10][11] and adsorbents [12][13] . Metaloxides constitute an important class of materials that are involved in environmental science, electrochemistry, biology, chemical sensors, magnetism and other fields.…”

Synthesis and Characterization of Nontoxic Hollow Iron Oxide (α-Fe2O

“…The XRD pattern of hollow spheres of calcinated NPs is shown in Figure 5(a) that indicates the high crystalline form of iron oxide NPs due to the iron precursor used and also due to calcination (to remove the carbon core at high temperature). Before calcinations no crystalline peaks were observed indicating the amorphous structure [9]. XRD peaks can be well indexed to -Fe 2 O 3 crystals and rhombohedral phase with JCPDS card number 33-0664.…”

“…Among them, template methods are the most effective way to produce hollow structures and are used typically for the synthesis of core shell structure leading to the coating of desired materials on the templates followed by the removal of templates. Hard and soft templates of different types are being used for instance carbon, acting as hard templates while emulsions, gas bubble, vesicles, and micelles were performing the soft template materials [9]. Template methods are most effective in the formation of hollow structures in accordance with the uniformity [10].…”

“…These NPs can be used in various applications in the field of nanoscience and technology. [9]. To synthesize the hollow iron oxide NPs, a carbonaceous additive, glucose (5.5 g), was mixed in 20 mL of distilled water and 5 M iron precursor (NH 4 ) 2 Fe(SO 4 ) 2 ⋅6H 2 O was dissolved in 10 mL of distilled water in a ratio of 5 : 1.…”

Tailoring Iron Oxide Nanostructures for High-Capacity Lithium Storage

“…[68] In 2009, Song et al reported a Kirkendall-effect-assisted strategy for the fabrication of α-Fe2O3 (Figures 3a and 3b) and carbon encapsulated α-Fe2O3 (α-Fe2O3@C) hollow nanoparticles. [69] The synthesis generally involved two steps, the preparation of Fe3C@C nanoparticles via co-carbonization and the controlled oxidation of Fe3C@C nanoparticles. During the controlled oxidation, Fe3C@C was converted into either α-Fe2O3@C (280 °C for 5 h) or pure α-Fe2O3 hollow nanoparticles (280 °C for 24 h) through nanoscale Kirkendall effect.…”