Synthesis of Mesoporous α-Fe₂O₃ Nanostructures for Highly Sensitive Gas Sensors and High Capacity Anode Materials in Lithium Ion Batteries

Abstract

Mesoporous α-Fe2O3 materials were prepared in large quantity by the soft template synthesis method using the triblock copolymer surfactant F127 as the template. Nitrogen adsorption−desorption isothermal measurements and transmission electron microscope observation revealed that the as-prepared mesoporous α-Fe2O3 nanostructures have large mesopores in a wide size range of 5−30 nm. It has been found that the Morin transition depends on thermal history of mesoporous α-Fe2O3, which is driven by surface anisotropy. Superparamagnetic behavior of mesoporous α-Fe2O3 is also associated with surface spins with blocking temperature around 50 K. When applied as gas sensors, mesoporous α-Fe2O3 nanostructures exhibited high gas sensitivity toward acetic acid and ethanol gas. As anodes in lithium ion cells, mesoporous α-Fe2O3 materials show a high specific capacity of 1360 mAh/g with excellent cycling stability and high rate capacity.

Porous Flower-like α-Fe2O3 Nanostructure: A High Performance Anode Material for Lithium-ion Batteries

“…Among the transition metal oxides, hematite (α-Fe 2 O 3 ) has attracted great interest due to its favorable properties, such as low cost, good stability, nontoxicity, and environmental friendly properties. It has been studied for applications in Li-ion batteries [7][8][9][10], supercapacitors [11][12][13], magnetic materials [14,15], catalytic agents [16], gas sensors and so on [17,18].…”

“…The theoretical capacity of α-Fe 2 O 3 is high at 1007 mAh g -1 assuming 6 Li per formula unit [7][8][9][10][19][20][21][22]. One of the most challenging issues is to maintain its electrochemical stability during cycling.…”

Two-Step Synthesis of V2O5 Nanosheets with High Sensing Properties toward Acetone

“…In this process, electrons will transfer to the surface of V2O5 to lower the number of trapped electrons, which induces a decrease in the resistance. [16] The diffusion rates of gas molecules are dependent on temperatures, thus the working temperature significantly may affect both the response and the sensitivity. Fig.…”

Structural, Morphological, and Magnetic Properties of the Mesoporous Maghemite Synthesized by a Citrate Method

“…Одержані значення питомих площ поверхонь є вищими порівня-но з літературними даними для мезопористих оксидів заліза [21,22] та змінюються залежно від температури відпалу в межах 130-180 м 2 /г та 115-135 м 2 /г для серій 0,3 М та 0,5 М відповідно. Для серії 0,3 М спостерігається різке зменшення питомої поверхні на 30 м 2 /г у діяпазоні температур 125-150С.…”