Effect of Germanium Incorporation on the Electrochemical Performance of Electrospun Fe2O3 Nanofibers-Based Anodes in Sodium-Ion Batteries

Abstract

Fe2O3 and Fe2O3:Ge nanofibers (NFs) were prepared via electrospinning and thoroughly characterized via several techniques in order to investigate the effects produced by germanium incorporation in the nanostructure and crystalline phase of the oxide. The results indicate that reference Fe2O3 NFs consist of interconnected hematite grains, whereas in Fe2O3:Ge NFs, constituted by finer and elongated nanostructures developing mainly along their axis, an amorphous component coexists with the dominant α-Fe2O3 and γ-Fe2O3 phases. Ge4+ ions, mostly dispersed as dopant impurities, are accommodated in the tetrahedral sites of the maghemite lattice and probably in the defective hematite surface sites. When tested as anode active material for sodium ion batteries, Fe2O3:Ge NFs show good specific capacity (320 mAh g−1 at 50 mA g−1) and excellent rate capability (still delivering 140 mAh g−1 at 2 A g−1). This behavior derives from the synergistic combination of the nanostructured morphology, the electronic transport properties of the complex material, and the pseudo-capacitive nature of the charge storage mechanism.

The production of highly efficientvisible‐light‐driven electrospunα‐Fe2O3photocatalyst through modifying iron source material for wastewater treatment applications

“…Araujo and co-researchers reported the avarage fiber diameter of electrospun Fe 2 O 3 was 360 nm with a diameter distribution ranging from 200 to 900 nm, calcinated at 800 C using Iron (III) nitrate nonahydrate and polyvinylpyrrolidone [65]. Another work executed by Petrovicovà and coworkers reported that the diameters of hematite fibers calcined for 2 h at 600 C varied between 120 and 500 nm using iron (II) acetate and polyacrylonitrile (PAN) as precursors [66]. In that study, the smaller average diameter of hematite fibers could be fabricated at a lower calcination temperature.…”

Flexible MoS2 Anchored on Ge-Containing Carbon Nanofibers

“…Moreover, carbon nanofibers with fine fiber diameters additionally improve the active sites in the electrode structure. The nano-sized active materials on carbon nanofibers increase the ion transport rates in rechargeable batteries [ 16 , 17 ].…”

Effect of Sn valence state in the in situ growth of FeOOH precursor on the performance of the α-Fe2O3 photoanode

“…In the last decades, enormous efforts have been made to improve its electrical conductivity, including foreign-ion doping or forming heterojunctions with other materials to enhance charge separation and transfer. 22,23 Metal ion doping in the α-Fe 2 O 3 lattice (such as Sn, 24 Ti, 25 Si, 26 Pt, 27 Zr, 28 Ge, 29 Cr, 30 and Zn 31 ) is found to be an effective method to improve its bulk transport property. Among various dopants, Sn 4+ doping by surface treatment and by self-Sn diffusion from an underlying fluorine doped SnO 2 (FTO) substrate has attracted great attention because Sn ion is subtly different in ionic radius and Pauling electronegativity compared to Fe ion.…”