Seed-assisted growth of α-Fe₂O₃ nanorod arrays on reduced graphene oxide: a superior anode for high-performance Li-ion and Na-ion batteries

Abstract

The α-Fe 2 O 3 nanorods/reduced graphene oxide nanosheets composites (denoted as α-Fe 2 O 3 @r-GO NRAs) are fabricated by a facile and scalable seeds-assisted hydrothermal growth route, in which the α-Fe 2 O 3 nanorods are assembled onto the side surfaces of r-GO nanosheets. Such α-Fe 2 O 3 @r-GO hybrid nanostructures are tested as anodes for both Li-ion and Na-ion batteries (LIBs and SIBs), which exhibits excellent performance with high capacity and long-cycling stability. When used for LIBs, the hybrid α-Fe 2 O 3 @r-GO NRAs electrode exhibits a highly stable Li + storage capacity of 1200 mAh g -1 after 500 cycles at 0.2 C and excellent rate capability. Moreover, the hybrid α-Fe 2 O 3 @r-GO NRAs also displays its versatility as an anode for SIBs, which delivers high reversible Na + storage capacity of 332 mAh g -1 at 0.2 C over 300 cycles with long-term cycling stability. The excellent electrochemical performance for the hybrid α-Fe 2 O 3 @r-GO NRAs anodes could be ascribed to the synergistic effect between the α-Fe 2 O 3 nanorods arrays and reduced graphene oxide nanosheets, which could availably promote the charge transport and accommodate the volume change upon long-term charge-discharge process for reversible Li + or Na + storage.

N-Doped Modified Graphene/Fe2O3 Nanocomposites as High-Performance Anode Material for Sodium Ion Storage

“…Therefore, the studies on the electrochemical performance of SIBs carried out later were based on the ether electrolytes. Figure 5b shows the first three cycles of the CV curve for the N-GF-300 electrode measured at a scan rate of 0.05 mVs −1 at a range of 0.005-3 V. According to previous reports, the insertion and extraction of sodium ions in Fe 2 O 3 is based on the following reaction [5,10,16,17]:…”

“…In the first CV curve from Figure 5b, there are two cathode peaks appearing at 0.5 and 0.89 V, respectively, due to the formation of the SEI film and the produce of Na x Fe 2 O 3 from the insertion of sodium ions into the Fe 2 O 3 . In the second CV curve, the cathode peaks at 0.63 and 0.94 V are accompanied by anode peaks at 0.6 and 1.6 V, which correspond to the reversible redox reaction of Fe 3+ ↔Fe 2+ and Fe 2+ ↔Fe 0 [5,16]. Figure 5c provides a comparison of the CV curves of the three electrode materials of GF, GF-300 and N-GF-300 at a scan rate of 1 mV s −1 .…”

“…However, there are still some obstacles hindering the practical application of sodium ion energy storage devices, such as poor rate performance, low coulombic efficiency, and undesirable Nanomaterials 2019, 9, 1770 2 of 13 cycle stability. The foremost reason is the bigger radius of Na + (0.102 nm) compared to Li + (0.076 nm), which leads to low reaction kinetics for Na + insertion/extraction from the anode materials [4][5][6]. Meanwhile, excellent anode materials should have suitable microscopic internal structures that can accommodate the lager Na + and enable reversible insertion/extraction electrochemical behavior, and should also be compatible with electrolytes, cost-efficient, and easy to prepare.…”

3D Branched Ca‐Fe2O3/Fe2O3 Decorated with Pt and Co‐Pi: Improved Charge‐Separation Dynamics and Photoelectrochemical Performance

“…[8,9] However,i ts low photoconversion efficiency owing to the high electron-hole recombination and sluggisho xygen-evolutionk inetics greatlyr estrict its practical application. [8,9] However,i ts low photoconversion efficiency owing to the high electron-hole recombination and sluggisho xygen-evolutionk inetics greatlyr estrict its practical application.…”

“…So far,h ematite (a-Fe 2 O 3 )h as been identified as an efficient and low-cost catalyst for solar water oxidation by virtue of its ideal energy bandgap ( % 2.1 eV), abundance,n ontoxicity,a nd excellent stability,a sd emonstrated in both theoretical ande xperimental investigations. [8,9] However,i ts low photoconversion efficiency owing to the high electron-hole recombination and sluggisho xygen-evolutionk inetics greatlyr estrict its practical application. [10] Effective methods to address these challenges include doping with foreign elements or constructing junction structures;i np articular,d oping with monovalent or divalent ions is thought to increase positivec hargec arriers and, thus, convert hematite to ap -type semiconductor.F or instance, Li et al [11] have integrated methods of doping andh eterojunction formation to fabricate aN iO/P-a-Fe 2 O 3 photoanode, which presentsahigh photocurrentd ensity of 2.08 mA cm À2 at 1.23 V vs. reversible hydrogen electrode (RHE).…”