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Ferromagnetic glass-ceramics and glass fibers were obtained by the melt-method from the glass system SiO 2 -CaO-Al 2 O 3 -B 2 O 3 -Fe 2 O 3 without performing any nucleation and crystallization heat treatments. Glass-ceramics and glass fibers were characterized by x-ray diffraction, scanning and transmission electron microscopy, magnetic measurements, and thermal expansion instrument. The influence of alumina content on the spontaneous crystallization of magnetite, magnetism properties and thermal expansion performances in glass were investigated. We examined the crystallization behavior of the glasses and found that the spontaneous crystallization capacity of magnetite and magnetism properties in base glass increases with increasing the content of alumina. The ferromagnetic glass fibers containing magnetite nano-crystals are also obtained. [ABSTRACT FROM AUTHOR]

Searching the high rate Fe 3 O 4 -based materials for lithium ion batteries (LIBs) is still a great challenge. Here we tackle this problem by developing a facile and green method which uses the natural cotton as a biotemplate and a activity biocarbon source. By this new method, we synthesized the mesoporous biocarbon fibers adhered with Fe 3 O 4 /Fe nanoparticles (Fe 3 O 4 /Fe/MBCFs). Fe 3 O 4 /Fe/MBCFs are a highly stable anode material for high-rate LIBs due to its excellent cycling performance at higher current and fast charging feature. This anode shows a high reversible capacity of 472 mAh g −1 after 500 cycles and can be rapidly charge to 100% in 28.3 min. After 160 cycles at varied current densities from 1 A g −1 to 10 A g −1 , it still delivered a high discharge capacity of 524.6 mAh g −1 and an ultra-high coulombic efficiency close to 100%. This is attributed to the synergistic effects of several factors including the unique mesoporous hybrid construction, the graphitized biocarbon fibers and the chemical bonding between Fe 3 O 4 and Fe nanoparticles. This work is instructive for fabrication and design of nanostructured electrodes with extraordinary properties from biomass renewable resources. [ABSTRACT FROM AUTHOR]