Microwave assisted synthesis of α-Fe₂O₃/reduced graphene oxide as anode material for high performance lithium ion batteries

Abstract

α-Fe 2 O 3 /reduced graphene oxide (RGO) nanocomposites were synthesized by a rapid and simple microwave method. Fe(OH) 3 sol was used as the precursor of α-Fe 2 O 3 . Under the microwave heating, graphene oxide (GO) was reduced to RGO using hydrazine hydrate as a reductant and Fe(OH) 3 sol transformed to α-Fe 2 O 3 particles attached uniformly onto RGO surfaces at the same time. The structure, morphology and composition of α-Fe 2 O 3 /RGO nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis and Raman spectrum. The electrochemical characteristics were valuated by coin-type cells versus metallic lithium and cyclic voltammetry. The prepared α-Fe 2 O 3 /RGO nanocomposites exhibited high reversible specific capacity of 650 mA⋅h⋅g -1 after 50 cycles at a current density of 1.0 A⋅g -1 , showing more superior rate capability than both of α-Fe 2 O 3 nanoparticles and RGO sheets themselves. At the larger current density of 10.0 A⋅g -1 , the capacity of α-Fe 2 O 3 /RGO nanocomposites still remained 400 mA⋅h⋅g -1 . The significant improvements in the electrochemical properties of α-Fe 2 O 3 /RGO nanocomposite could be attributed to the uniform α-Fe 2 O 3 nanoparticles (30-50 nm) on the RGO substrate which provided high electrical conductivity, confined the position and buffered the volume changes of α-Fe 2 O 3 nan stability and electrochemical activity, γ-Fe 2 O 3 and Fe 3 O 4 are spinel structure exhibiting very good electrical conductivity and so on. As other transition oxides, iron oxides as lithium ion battery anode materials will generate great volume-stress with huge volume changes between iron oxides and iron atoms in the process of charging and discharging. The process will breakdown crystal structures, short cycle life and cause capacity loss. Wu et al. [29] highlighted that the lithium storage capability would be further increased by designing advanced nanocomposite materials including metal oxides and carbonaceous supports. Two-dimensional (2D) graphene is the basic composition unit of 0D buckyballs, 1D nanotubes and 3D graphite and it has excellent electrochemical property [30] .Furthermore, lithium ion can also be inserted or extracted on both sides of the RGO [31] . Given all this, many attempts have been done to prevent it with electrospinning method [22,23] , hydrothermal method [19,24,[32][33][34]37,38] , microwave method [16,27,31] and chemical vapor deposition [20,21,26] et al. by preparing composite materials with carbon nanotubes [15,19] and graphene [16,20,21,24,27,[31][32][33][34][36][37][38][39] , coating iron oxides by carbon [20,25,26] and synthesis nano-sized iron oxides [17] , etc. Iron oxides anchored on graphene preparing nanocomposites as anodes of lithium ion batteries is a research spots and the composites' perfect performance as anodes of lithium ion battery have been shown. Zhang et al. [24] manufactured Fe 2 O 3 /GO nanocomposites by hydrothermal reaction and then prepared Fe 3 O 4 /RGO nanocompo...

Continuous Hydrogenation of Ethyl Levulinate to 1,4‐Pentanediol over 2.8Cu‐3.5Fe/SBA‐15 Catalyst at Low Loading: The Effect of Fe Doping

“…The high‐resolution (HR)TEM images of 2.8Cu‐3.5Fe/SBA‐15 are shown in Figure . The clear lattice fringes of 0.232, 0.244, and 0.367 nm (Figure A–C) correspond to the d spacings of the (1 1 1) plane of CuO, (1 1 1) plane of Cu 2 O, and (0 1 2) plane of Fe 2 O 3 . The interplanar spacings of 0.250, 0.224, and 0.284 nm (Figure D–F) correspond to (0 1 2), (1 0 4), and (0 0 6) planes of CuFeO 2 .…”

Highly uniform Fe3O4 nanoparticle–rGO composites as anode materials for high performance lithium-ion batteries

“…1. As the surface of the GO nanosheets has oxygen-containing groups, Fe(OH) 3 nanoparticles can be uniformly adsorbed on the surface, forming Fe(OH) 3 /GO nanocomposites under electrostatic force, 37 which was veried by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses ( Fig. S1a-c †).…”

Synthesis and Applications of Graphene/Iron(III) Oxide Composites

“…In this section, most of the 0D structures refer to nanoparticles (NPs) and the common morphology of graphene / α ‐Fe 2 O 3 composites is α ‐Fe 2 O 3 NPs anchored on graphene, which are mainly synthesized by two strategies. One strategy is to obtain α ‐Fe 2 O 3 NPs / graphene composites directly by the simple hydro/solvothermal method at 180 °C for 12 h. Another strategy is a two‐step method that first obtains the precursors of NPs such as Fe(OH) 3 or FeOOH NPs, and prepares the products by a subsequent microwave method or annealing process, respectively.…”