α-Fe₂O₃ Nanorods as Anode Material for Lithium Ion Batteries

Abstract

Hydrothermally synthesized single-crystalline hematite (α-Fe 2 O 3 ) nanorods were investigated as an anode material for Li-ion batteries. Electrodes prepared with this material exhibited initial reversible capacities of 908 mAh g À1 at 0.2 C rate and 837 mAh g À1 at 0.5 C rate, and these capacities were completely retained after numerous cycles. The α-Fe 2 O 3 nanorods average ∼40 nm in diameter and ∼400 nm in length providing a short path for lithium-ion diffusion and effective accommodation of the strain generated from volume expansion during the lithiation/delithiation process.

Imidazolium ionic liquid induced one-step synthesis of 𝜶-Fe2O3 nanorods and nanorod assemblies for lithium-ion battery

“…Agreed well with the above CV analysis, the charge-discharge curves during de-lithiation are consistent with the reversible redox conversion of α-Fe 2 O 3 to Fe 0 and Li 2 O by the overall following half reaction: α-Fe 2 O 3 + 6Li + + 6e → 2Fe 0 + 3Li 2 O. [29][30][31] The first Li-insertion is noted between 2.0 and 1.1 V vs. Li (Li x Fe 2 O 3 ), and the second insertion is observed between 1.1 and 0.75 V. A long distinct plateau at ∼0.8 V supports the complete destruction of the Fe 2 O 3 lattice and decomposition of the electrolyte solution as well. In addition, electrochemical impedance spectroscopy (EIS, Fig.…”

“…32 Similar behavior for the α-Fe 2 O 3 electrode has been reported in previous studies, which arose from an activation process. 32,33 After 250 cycles, the capacity still remains 883 mA h g 1 which is much higher than that of porous α-Fe 2 O 3 nanorods (314 mA h g 1 ) 30 and the Fe 2 O 3 -based composites (500-600 mA h g 1 ), [32][33][34][35][36][37] as summarized in Table I. For instance, the α-Fe 2 O 3 rhombohedra with nearly 100% exposed (104) facets only exhibited a reversible capacity of 550 mA h g 1 after 120 cycles at a current density of 200 mA g 1 .…”

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.…”

Tailoring Iron Oxide Nanostructures for High-Capacity Lithium Storage

“…However, the high specific capacity is accompanied by a large volume change (~96%) during lithiation/ de-lithiation. [20] Such a large volume variation results in the notorious problems of active material pulverization, electrode disintegration (loss of electrical contact between active material and current collector), and unstable solid electrolyte interphase (SEI) film formation, eventually leading to rapid capacity fading upon cycling. To achieve high specific capacity without compromising the cyclability, the volume change associated with repeated lithiation/de-lithiation should be better accommodated.…”