Graphene Oxide Composite Anode Research Articles

Erythrocyte-like Fe2O3@SnO2 heterostructures anchored on graphene oxide composite anode material for high-performance lithium-ion battery

Erythrocyte-like Fe2O3@SnO2 heterostructures anchored on graphene oxide composite anode material for high-performance lithium-ion battery

Electrochemical characterization of γ-Fe2O3 and reduced graphene oxide composite as a sustainable anode material for Na-ion batteries

In this paper we report the synthesis and characterization of a γ-Fe2O3/reduced graphene oxide composite anode for Na-ion batteries. The nanocomposite anode is synthesized by a facile and green method....

One pot synthesis of Sb2O3/reduced graphene oxide composite anode material for sodium ion batteries

Antimony-based oxide anode shows high capacity but poor cycle performance. After introducing reduced graphene oxide (rGO), the cycle performances are significantly improved. However, special treatments are required for these composite. Herein, a room temperature, one pot synthesis of antimony oxide/reduce graphene oxide composite with addition of hydrazine hydrate is developed. In the synthesis, GO is reduced by hydrazine hydrate which also prevent the oxidation of Sb3+ to Sb5+. In addition, hydrazine hydrate efficiently suppresses the agglomeration of Sb2O3. The Sb2O3/rGO composite exhibits excellent rate capability and cycle performance owing to the good conductivity of rGO and strong chemical bonds between rGO and Sb2O3.

Synthesis of a zinc ferrite effectively encapsulated by reduced graphene oxide composite anode material for high-rate lithium ion storage

Effectively immobilizing nano-sized electrochemical active materials with a 3D porous framework constituted by conductive graphene sheets brings in enhanced lithium ion storage properties. Herein, a reduced graphene oxide (RGO) supported zinc ferrite (ZnFe2O4) composite anode material (ZnFe2O4/RGO) is fabricated by a simple and effective method. Firstly, redox reaction takes place between the oxygen-containing functional groups on few-layered graphene oxide (GO) sheets and controlled quantity of metallic Zn atoms. ZnO nanoparticles are in-situ nucleated and directly grow on GO sheets. Secondly, the GO sheets are completely reduced by abundant Fe atoms, and corresponding γ-Fe2O3 nanoparticles are formed neighboring the ZnO nanoparticles. In this step, 3D porous RGO supporting framework are constructed with γ-Fe2O3@ZnO nanoparticles effectively encapsulated between the RGO layers. Finally, the well-designed γ-Fe2O3@ZnO/RGO intermediate product undergoes a thermal treatment to allow a solid-state reaction and obtains the ZnFe2O4/RGO composite. At a high current rate of 1.0 A·g−1, the ZnFe2O4/RGO composite exhibits an inspiring reversible capacity of 1022 mAh·g−1 for 500 consecutive cycles as anode material for lithium ion batteries. And the insight into the attractive lithium storage performance has been studied in this work.

In-situ preparation of LixSn-Li2O–LiF/reduced graphene oxide composite anode material with large capacity and high initial Coulombic efficiency

Anode materials with large capacity have a growing application due to the booming electric vehicle and energy storage market. However, the low initial Coulombic efficiency (ICE) and poor cycle stability hinder their commercial development. Herein, we investigate the effective and convenient method of preparing LixSn-Li2O–LiF/reduced graphene oxide (LixSn-Li2O–LiF/RGO, Li-GFTO) composite anode material with large capacity and high ICE. Firstly, the highly-dispersed fluorine-doped tin oxide and reduced graphene oxide (F–SnO2/RGO, GFTO) composite is in-situ synthesized by one-pot reflux method. The fluorine-doped SnO2 nanocrystals are uniformly anchored on graphene sheets. Secondly, the F–SnO2/RGO was lithiated by reacting with the lithium dissolved in the solution of biphenyl and 1,2-dimethoxyethane to get LixSn-Li2O–LiF/RGO composite. The Li2O and LiF will be formed and prevent the diffusion and coarsening of Sn and LixSn during cycling. Used as the anode material, the ICE of the LixSn-Li2O–LiF/RGO composite is as high as 97%. The composite anode material also shows high cycling stability. The residual capacity is as high as 992 mAhg−1 at 0.1 Ag-1 after 100 cycles, and the charge capacity retention is 99%. Most of all, the mild preparation condition promotes the mass production and practical application of tin-lithium alloy based composite anode materials.

Porous Red Phosphorus and Reduced Graphene Oxide Composite Anode with High Capacity and Stability in a Sodium-Ion Battery

Rechargeable lithium-ion batteries (LIBs) with high energy density have been widely applied in portable electronic devices and electric vehicles. However, considering the increasing cost of lithium for LIBs due to geologically uneven distribution and limited supply of lithium resources, sodium-ion batteries (SIBs) have recently received attention as a candidate to replace LIBs because the sodium is the abundant element and low cost. Although the sodium and sodium ion have similar chemical/electrochemical properties to lithium/lithium ion, the major challenges still exist in developing anode materials because ionic radius of sodium ion (1.02 °A) is 34% larger than that of lithium ion (0.76 °A), which leads to difficulty in the intercalation of sodium ion into conventional anode materials for LIBs, such as graphite. Therefore, it is urgent and challenging to explore a suitable material with enough capacity and stable cycling performance for SIB anode. Recently, red phosphorous (Red P) has been considered as a new anode material for the SIBs due to its high theoretical specific capacity (2596 mAh g-1), low cost, and environmental friendliness. Nevertheless, it is difficulty to use the red P in practical applications, because the red P undergoes tremendous volume expansion (~300%) during sodiation/desodiation, resulting in the pulverization of the particles and formation of unstable solid electrolyte interphase (SEI). In this work, to solve the problematic behaviors of red P, we prepared the porous red P@RGO (Reduced Graphene Oxides) composite anodes to increase electrical/ionic conductivities and buffer the volume expansion. Figure 1 shows the TEM images of porous red P and porous red P@RGO composite. The red P exhibits porous surface morphology (Figure 1a), and the porous characteristics is expected to alleviate the volume expansion and offer fast sodium-ion transport. Additionally, to improve electrical conductivity, porous red P was loaded on the RGO in the form of composite. It was observed that the porous red P particles were successfully loaded and well distributed on RGO sheets (Figure 1b). The X-ray diffraction (XRD) pattern of commercial red P, porous red P, RGO, and porous red P@RGO composites are shown in Figure 2. The porous red P shows three peaks at 12.1-18°, 27-39°, and 45-67°, which is consistent with those of commercial red P.[2] Notably, the porous red P@RGO exhibits four broadened peaks at 12.5−17°, 19−27°, 28−41°, and 46−68°, corresponding to both of porous red P and RGO.[ 3 ,4] Figure 3 represents the cycling performance of porous red P@RGO and commercial red P at 0.1 A g-1 within the voltage range of 0.005−2.5 V. It is notable that the porous red P@RGO anodes shows much higher (more than five times) initial cycling performance (1214.6 mAh g-1) compared to the commercial red P anodes (185.4 mAh g-1) during 6 cycles. To elucidate the enhanced performance, the electrochemical, surface-chemical, and morphological analyses were performed using EIS, CV, XPS, XRD, HR-TEM, SEM/EDS and STEM/mapping.

Synthesis and Electrochemical Reaction of Tin Oxalate-Reduced Graphene Oxide Composite Anode for Rechargeable Lithium Batteries.

Unlike for SnO2, few studies have reported on the use of SnC2O4 as an anode material for rechargeable lithium batteries. Here, we first introduce a SnC2O4-reduced graphene oxide composite produced via hydrothermal reactions followed by a layer-by-layer self-assembly process. The addition of rGO increased the electric conductivity up to ∼10-3 S cm-1. As a result, the SnC2O4-reduced graphene oxide electrode exhibited a high charge (oxidation) capacity of ∼1166 mAh g-1 at a current of 100 mA g-1 (0.1 C-rate) with a good retention delivering approximately 620 mAh g-1 at the 200th cycle. Even at a rate of 10 C (10 A g-1), the composite electrode was able to obtain a charge capacity of 467 mAh g-1. In contrast, the bare SnC2O4 had inferior electrochemical properties relative to those of the SnC2O4-reduced graphene oxide composite: ∼643 mAh g-1 at the first charge, retaining 192 mAh g-1 at the 200th cycle and 289 mAh g-1 at 10 C. This improvement in electrochemical properties is most likely due to the improvement in electric conductivity, which enables facile electron transfer via simultaneous conversion above 0.75 V and de/alloy reactions below 0.75 V: SnC2O4 + 2Li+ + 2e- → Sn + Li2C2O4 + xLi+ + xe- → LixSn on discharge (reduction) and vice versa on charge. This was confirmed by systematic studies of ex situ X-ray diffraction, transmission electron microscopy, and time-of-flight secondary-ion mass spectroscopy.

Synthesis of Fe2O3/reduced graphene oxide composite anode materials with good cycle stability

Fe2O3/reduced graphene oxide (Fe2O3/rGO) composite anode materials have been successfully synthesized by a polyvinylpyrrolidone (PVP)-assisted homogeneous precipitation method. The size of Fe2O3 nanoparticles on the surface of rGO sheets was less than 35 nm. Fe2O3 nanoparticles and rGO sheets formed a network structure. Electrochemical properties were evaluated in two-electrode cells vs. metallic lithium. The Fe2O3/rGO composite exhibited excellent electrochemical lithium storage performances. The first discharge/charge capacities were 1600/1053 mA h g−1 at a current density of 100 mA g−1, and the coulomb efficiencies was 65.8%. The reversible specific capacity remained 893 mA h g−1 and the capacity retention was 84.8% after 100 cycles.

A ZnS nanocrystal/reduced graphene oxide composite anode with enhanced electrochemical performances for lithium-ion batteries

A simple route for the preparation of ZnS nanocrystal/reduced graphene oxide (ZnS/RGO) by a hydrothermal synthesis process was achieved. The chemical composition, morphology, and structural characterization reveal that the ZnS/RGO composite is composed of sphalerite-phased ZnS nanocrystals uniformly dispersed on functional RGO sheets with a high specific surface area. The ZnS/RGO composite was utilized as an anode in the construction of a high-performance lithium-ion battery. The ZnS/RGO composite with appropriate RGO content exhibits a high reversible specific capacity (780 mA h g-1), excellent cycle stability over 100 cycles (71.3% retention), and good rate performance at 2C (51.2% of its capacity when measured at a 0.1C rate). To further investigate this ZnS/RGO anode for practical use in full Li-ion cells, we tested the electrochemical performance of the ZnS/RGO anode at different cut-off voltages for the first time. The presence of RGO plays an important role in providing high conductivity as well as a substrate with a high surface area. This helps alleviate the typically problems associated with volume expansion and shrinkage during prolonged cycling. Additionally, the RGO provides multiple nucleation points that result in a uniformly dispersed film of nanosized ZnS that covers its surface. Thus, the high surface area RGO enables high electronic conductivity and fast charge transfer kinetics for ZnS lithiation/delithiation.

Scalable synthesis and superior performance of TiO2-reduced graphene oxide composite anode for sodium-ion batteries

TiO2-reduced graphene oxide (RGO) composite was synthesized via a sol-gel process and investigated as an anode material for sodium-ion batteries (SIBs). A remarkable improvement in sodium ion storage with a reversible capacity of 227 mAh g−1 after 50 cycles at 50 mA g−1 is achieved, compared to that (33 mAh g−1) for TiO2. The enhanced electrochemical performance of TiO2-RGO composite is attributed to the larger specific surface area and better electrical conductivity of TiO2-RGO composite. The excellent performance of TiO2-RGO composite enables it a potential electrode material for SIBs.

A silicon nanoparticle/reduced graphene oxide composite anode with excellent nanoparticle dispersion to improve lithium ion battery performance

Composite anodes of Si nanoparticles (SiNPs) and reduced graphene oxide (RGO) sheets with highly dispersed SiNPs were synthesized to investigate the performance-related improvements that particle dispersion can impart. Three composites with varying degrees of particle dispersions were prepared using different ultrasonication, and a combination of ultrasonication and surfactant. With more dispersed SiNPs, the capacity retention and rate performance as evaluated by galvanostatic cycling using increasing current density rates (500–2500 mA/g) also improved compared with anodes that have poor particle dispersion. These results demonstrate that better nanoparticle dispersion (small clusters to mono-dispersed particles) between the stable and the highly conducting RGO layers, allows the carbonaceous matrix material to complement the SiNP-Li+ electrochemistry by becoming highly involved in the charge–discharge reaction mechanisms as indicated by chronopotentiometry and cyclic voltammetry (CV). Particle dispersion improvement was confirmed to be a key component in a composite anode design to maximize Si for high-performance lithium ion battery (LIB) application.