Composite Anode Material Research Articles

Li4Ti5O12/C Composite Anode Material Synthesized Involving Absorbent Cotton for Li-Ion Battery

A puissant specific capacity spherical Li4Ti5O12 anode material of Lithium-Ion battery was successfully synthesized by two methods include a high-temperature solid-phase method using solid phase lithium and titanium sources, and a sol-gel method with liquid phase lithium and titanium sources. The carbon coating modification of Li4Ti5O12 anode material was carried out by adding absorbent cotton during the reaction process, and the effect of absorbent cotton addition on the structure, morphology and electrochemical performance of Li4Ti5O12 was studied. The composite prepared by sol-gel represents a superior first discharge specific capacity of 173 mAh·g−1 at 0.2 C rates, approximately 68 mAh·g−1 at 10 C rates, and the capacity of sample remained 103 mAh·g−1 after 100 cycles of 1 C rate charge/discharge process.

Synthesis and Performance of NaTi2(PO4)3/VGCF@C Anode Composite Material for Aqueous Sodium-Ion Batteries

This study combines self-prepared NaTi2(PO4)3 (NTP) with commercial vapor-grown carbon fiber (VGCF) using a solid state calcination, then coats it with carbon to synthesize the composite anode material NaTi2(PO4)3/VGCF@C (NTP/VGCF@C). The microstructure and electrochemical properties of the composite material were then analyzed using microstructure analysis and electrochemical testing equipment. Single phase NTP shows nanoparticles with a polyhedral structure, and there is good contact at the interface between the nanoparticles and the VGCFs. The carbon coating formed on the NTP particles displays a nearly 6.5 nm thick layer of amorphous carbon. From the coin-cell battery performance measurements, after 850 cycles, the composite material NTP/VGCF@C exhibits an excellent retention rate of 96.3% compared to that of the pure NTP material when the current density is 200 mA/g. As a result, the composite material and lithium manganate (denoted as LMO) were assembled into an LMO-NTP/VGCF@C aqueous sodium-ion soft pack full battery system. The full battery shows an initial capacity of 31.07 mAh at a rate of 0.5C, and a reversible discharge capacity retention rate of 95.8% after 480 cycles, exhibiting a good long-cycle stability performance.

High Coulomb Efficiency Sn-Co Alloy/rGO Composite Anode Material for Li-ion Battery with Long Cycle-Life.

The low cycle performance and low Coulomb efficiency of tin-based materials confine their large-scale commercial application for lithium-ion batteries. To overcome the shortage of volume expansion of pristine tin, Sn-Co alloy/rGO composites have been successfully synthesized by chemical reduction and sintering methods. The effects of sintering temperature on the composition, structure and electrochemical properties of Sn-Co alloy/rGO composites were investigated by experimental study and first-principles calculation. The results show that Sn-Co alloys are composed of a large number of CoSn and trace CoSn2 intermetallics, which are uniformly anchored on graphene nanosheets. The sintering treatment effectively improves the electrochemical performance, especially for the first Coulomb efficiency. The first charge capacity of Sn-Co alloy/rGO composites sintered at 450 °C is 675 mAh·g-1, and the corresponding Coulomb efficiency reaches 80.4%. This strategy provides a convenient approach to synthesizing tin-based materials for high-performance lithium-ion batteries.

A review on applications of carbon nanotubes-based metal-sulfide composite anode materials (CNTs/MS) for sodium (Na)-ion batteries

A review on applications of carbon nanotubes-based metal-sulfide composite anode materials (CNTs/MS) for sodium (Na)-ion batteries

Optimization of graphene dose for improved electrochemical performance of silicon–graphene negative electrodes in lithium batteries

Different percentages of nanoparticles graphene (G) were mixed with nano-micron sized silicon (Si) particles as follows: 10, 20, 30 and 40 wt% graphene to silicon ratios. The crystal structure of pure Si powder pattern has cubic phase SEM, TEM/SAED and XPS equipments were implemented to study the surface properties of the prepared G@Si composites. Cyclic voltammetry (CV) measurement for the G@Si cell revealed two broad cathodic peaks, related to the deposition of Li2O thin layer on Si particles and the lithiation process of Si to form lithium silicide. Meanwhile, the oxidation of LixSi into Si and Li ionis confirmed by the anodic strong peak at 0.56 V. Electrochemical impedance spectroscopy (EIS) measurements revealed high interfacial resistance ~ 1825 Ω for pure Si anode in comparison with that of G@Si composite anode. It is concluded that graphene acts as a conductive shielding pathway to inhibit the large volume change and minimize the capacity fading during successive galvanostatic cycling of G@Si composite anode materials versus Li/Li+. Accordingly, the specific discharge capacity of 30%G@Si cell delivered about 1240 and 900 mAhg−1 for 1st and 100th charge–discharge cycles, respectively.

A study on corrosion behavior of FeSi alloy matrix composites using wire beam electrode

In order to obtain high performance anode material of lithium ion battery, four samples of FeSi alloy base composites were synthesized by simple solid−state reaction. The anode active materials, which consist of Al, Cu, C, and C/Cu with FeSi alloy respectively, were heated to 700 °C under continuous argon flow to obtain four composite anode materials to improve electrical conductivity and corrosion resistance. In addition. The corrosion behavior of these four composite anode materials in electrolyte solution were studied by Cu wire beam electrode (WBE). The morphology and composition of the composite anode materials were analyzed by scanning electron microscope (SEM). The results show that the four nano−powders can be uniformly coated on the surface of FeSi alloy. The results of WBE test show that the corrosion resistance of C/Cu doped samples is the best, which is attributed to the C and Cu of strong conductivity can increase the conductivity, enhance corrosion resistance, reduce the internal resistance and mechanical stress of FeSi alloy anode.

Three-dimensional cage-like structured VOF@CNT composite material: In situ one-step synthesis and high-performance as the anode for lithium-ion batteries

Fabricating composites with three-dimensional (3D) nano-vanadium-based oxides and with carbon materials is one of the most effective ways to improve the performance of anode materials for lithium-ion batteries (LIBs). Herein, we firstly synthesized 3D V2O5 flowers (VOF) composed of interconnected ultrathin nanobelts through the surfactant-induced hydrothermal method, using vanadium pentoxide (V2O5) as vanadium source and carbon nanotubes as the carbon matrix. And then, the 3D VOF@CNT composite anode material was successfully prepared by in-situ bonding carbon nanotubes (CNT). Test results showed that the CNT can effectively inhibit the agglomeration of VOF nanoparticles, and thereby optimize the composite anode material's cycling stability and electrical conductivity. Meanwhile, as the carrier of lithium-ion (Li+), the VOF has a unique petal-like structure, which not only contributes to the Li+ diffusion and electron (e-) transport along the radial direction, but also provides sufficient space for the storage of Li+ and relieves the volume change of electrode during the cycle. Therefore, the composite electrode material still maintains at a high capacity of 417.7 mAh·g−1 after 200 cycles when the current density is 0.1 A·g−1. This work provides a method for preparing transition metal oxide electrode materials with great electrochemical performance and cycle stability.

Combine Natural Stibnite with Bio-Carbon: A High-Capacity Composite Anode Material for Lithium-Ion Battery

Combine Natural Stibnite with Bio-Carbon: A High-Capacity Composite Anode Material for Lithium-Ion Battery

Graphene‐Encapsulated Nitrogen‐doped Carbon@Bi Enables Rapid, Ultrahigh and Durable Sodium Storage

AbstractBismuth (Bi) has promising applications as anode in sodium‐ion batteries (SIBs) due to its suitable alloy voltage, unique lattice structure and high volumetric specific capacity. However, the severe structural degradation and poor cycling performance of Bi‐anode during cycling limits its practical application. Here, we designed and synthesized graphene‐encapsulated nitrogen‐doped carbon@bismuth (N−C@Bi/G) composites as anode materials for SIBs by a two‐step hydrothermal and thermal treatment method to solve the above problems. The N−C@Bi/G composite anode material exhibits excellent sodium storage performance, high capacity (280 mAh g−1 at 0.1 A g−1 and an initial coulombic efficiency of 78.87 %) and long‐term cycling stability (260 mAh g−1 after 1000 cycles at 2 A g−1). Electrochemical analysis and DFT calculations show that the fast reaction kinetics of N−C@Bi/G is directly related to the introduction of nitrogen‐doped carbon enriching the pore structure and increasing the active sites. Meanwhile, through the aid of in‐situ X‐ray diffraction (XRD), the reaction mechanism and interphase evolution of N−C@Bi/G composite are revealed, which provides an important theoretical basis for the application of SIBs.

Extraordinary Ultrahigh‐Capacity and Long Cycle Life Lithium‐Ion Batteries Enabled by Graphitic Carbon Nitride‐Perylene Polyimide Composites

Graphitic carbon nitride (g–C3N4) is widely used in organic metal‐ion batteries owing to its high porosity, facile synthesis, stability, and high‐rate performance. However, pristine g–C3N4 nanosheets exhibit poor electrical conductivity, irreversible metal‐ion storage capacity, and short‐term cycling owing to their high concentration of graphitic–N species. Herein, a series of 3,4:9,10‐perylenetetracarboxylic diimide‐coupled g–C3N4 composite anode materials, CN–PIx (x = 0.2, 0.5, 0.75, and 1), was investigated, which exhibited an unusually high surface nitrogen content (23.19–39.92 at.%) and the highest pyridinic–N, pyrrolic–N, and graphitic–N contents reported to date. The CN–PI1 anode delivers an unprecedented and continuously increasing ultrahigh discharging capacity of exceeding 8400 mAh g−1 (1.96 mWh cm−2) at 100 mA g−1 with high specific energy density (Esp) of ∼7700 Wh kg−1 and the volumetric energy density (Ev) of ∼14956 Wh L−1 and an excellent long‐term stability (414 mAh g−1 or 0.579 mWh cm−2 at 1 A g−1). Furthermore, the activation of the CN–PIx electrodes contributes to their superior electrochemical performance, resulting from the fact that the Li+ is not only stored in the CN–PIx composites but also CN–PIx activated the Li0 adlayer on the CN–PI1–Cu heterojunction as an SEI layer to avoid the direct contact of Li0 phase and the electrolyte. The CN–PI1 full cell with LiCoO2 as the cathode delivers a discharge capacity of ∼587 mAh g−1 at a 1 A g−1 after 250 cycles with a Coulombic efficiency nearly 99%. This study provides a strategy to develop N‐doped g–C3N4‐based anode materials for realizing long‐lasting energy storage devices.

Synthesis and Electrochemical Properties of Co3O4@Reduced Graphene Oxides Derived from MOF as Anodes for Lithium-Ion Battery Applications

In this study, we utilized nano-sized Co3O4 and reduced graphene oxides (rGOs) as composite anode materials for Li-ion batteries. The Co3O4/C composite anode was derived from ZIF67 (Zeolitic Imidazolate Framework-67) and was wrapped in rGOs through precipitation. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to identify the crystal structure, phase purity, and surface morphology of the composite. The composition-optimized Co3O4/rGO/C composite anode exhibited a reversible capacity of 1326 mAh/g in the first cycle, which was higher than that of the Co3O4/C composite anode with a capacity of 900 mAh/g at a current density of 200 mA/g. Moreover, after 80 cycles, Co3O4/rGO/C maintained a capacity of 1251 mAh/g at the same current density, which was also higher than the bare Co3O4/C composite (595 mAh/g). Additionally, the Co3O4/rGO/C composite exhibited a good capacity retention of 98% after 90 cycles, indicating its excellent cycling stability and high capacity. Therefore, the Co3O4/rGO/C electrode has great potential as a promising anode material for Li-ion batteries.

Development and Validation of a ReaxFF Reactive Force Field for Modeling Silicon–Carbon Composite Anode Materials in Lithium-Ion Batteries

Silicon–carbon (Si–C) nanocomposites have recently established themselves among the most promising next-generation anode materials for lithium (Li)-ion batteries. Indeed, combined Si and graphitic (sp2-C) phases exhibit high energy densities with reasonable electrochemical responses, while covalently bonded silicon carbide (SiC) compounds offer high mechanical stiffness to withstand structural degradation. However, to form and utilize a Si–C composite structure that effectively satisfies specific battery energy, power, and lifetime requirements, it is necessary to understand the underlying atomistic mechanisms at work within its individual phases and at their interfaces. Here, we develop and validate a reactive interatomic potential (ReaxFF) for the Li–Si–C system, trained and tested against a large, diverse collection of ab initio data. In conjunction with molecular dynamics and Monte Carlo simulations, our new force field links macroscale phenomena to the nanostructures of various hybrid Si–C systems in a wide range of lithiation, temperature, and stress conditions. As an illustration, it demonstrates that the high capacity of SiC (5882 mA h g–1) is caused by amorphous lithium carbides (e.g., a-Li4.4C), which soften the overall a-Li4.4(SiC)0.5 system while swelling it volumetrically up to 668%. Furthermore, our force field accurately depicts step-wise lithiation mechanisms and volume changes in Si–sp2-C composites throughout the lithiation domain of each host subsystem. It reveals the formation of a Li-rich interphase at their grain boundary, which favors their adhesion and increases the local Li (de)insertion voltage up to 1 V. These examples demonstrate the ability of the new Li–Si–C ReaxFF potential to provide atomistic-scale insights required for designing and optimizing a wide range of Si–C-based anode candidates for upcoming Li-ion battery technologies.

Defect mediated lithium adsorption on graphene-based silicon composite electrode for high capacity and high stability lithium-ion battery

Carbon-coated silicon materials are considered as promising anode materials in high-capacity lithium-ion batteries (LIBs). Theoretically, using graphene as the anode material in the LIB would afford high electrical conductivity, mechanical stability of Si, and suppression of the unstable solid–electrolyte interface. However, its usage is hindered by its electrochemical characteristic, which is not electrochemically active when combined with lithium. Therefore, research on graphene as the anode and coated material in LIBs has been conducted using defect engineering to enhance the storage capacity of graphene. Although the electrochemical characteristics of various defects in graphene have been studied experimentally and theoretically, graphene-based composite anode materials such as graphene–silicon composite electrodes have rarely been studied from the electrochemical and mechanical perspectives. In this study, lithium adsorptions are conducted on various defected graphene and graphene–silicon composites using density functional theory calculation. The formation energies of Li on the various defected graphene are assessed, and the mechanical strengths of the graphene–silicon composites are analyzed. Our calculations validate that the defects in graphene enhance the electrochemical adsorptions and interfacial mechanical strengths of the graphene and graphene–silicon composites. During lithiation, the defects mediate greater interfacial adhesion of the silicon–graphene composite. Hence, we elucidate that defected graphene increases the electro-chemo mechanical stabilities of silicon composites in high-capacity LIBs.

Synthesis of C/SiC Mixtures for Composite Anodes of Lithium-Ion Power Sources

Nowadays, research aimed at the development of materials with increased energy density for lithium-ion batteries are carried out all over the world. Composite anode materials based on Si and C ultrafine particles are considered promising due to their high capacity. In this work, a new approach for carbothermal synthesis of C/SiC composite mixtures with SiC particles of fibrous morphology with a fiber diameter of 0.1–2.0 μm is proposed. The synthesis was carried out on natural raw materials (quartz and graphite) without the use of complex equipment and an argon atmosphere. Using the proposed method, C/SiC mixture as well as pure SiC were synthesized and used to manufacture anode half-cells of lithium-ion batteries. The potential use of the resulting mixtures as anode material for lithium-ion battery was shown. Energy characteristics of the mixtures were determined. After 100 cycles, pure SiC reached a discharge capacity of 180 and 138 mAh g−1 at a current of C/20 and C, respectively, and for the mixtures of (wt%) 29.5C–70.5 SiC and 50Si–14.5C–35.5SiC discharge capacity of 328 and 400 mAh g−1 at a current of C/2 were achieved. The Coulombic efficiency of the samples during cycling was over 99%.

Silicon/Graphite/Amorphous Carbon as Anode Materials for Lithium Secondary Batteries.

Although silicon is being researched as one of the most promising anode materials for future generation lithium-ion batteries owing to its greater theoretical capacity (3579 mAh g-1), its practical applicability is hampered by its worse rate properties and poor cycle performance. Herein, a silicon/graphite/amorphous carbon (Si/G/C) anode composite material has been successfully prepared by a facile spray-drying method followed by heating treatment, exhibiting excellent electrochemical performance compared with silicon/amorphous carbon (Si/C) in lithium-ion batteries. At 0.1 A g-1, the Si/G/C sample exhibits a high initial discharge capacity of 1886 mAh g-1, with a high initial coulombic efficiency of 90.18%, the composite can still deliver a high initial charge capacity of 800 mAh g-1 at 2 A g-1, and shows a superior cyclic and rate performance compared to the Si/C anode sample. This work provides a facile approach to synthesize Si/G/C composite for lithium-ion batteries and has proven that graphite replacing amorphous carbon can effectively improve the electrochemical performance, even using low-performance micrometer silicon and large size flake graphite.

Functionalised graphite felt anodes for enhanced power generation in membrane-less soil microbial fuel cells

Testing composite carbon-based anode materials for high-perfoming soil microbial fuel cells.

A facile precursor route towards the synthesis of Fe1-xS@NC-rGO composite anode materials for high-performance lithium-ion batteries.

Iron-based sulfides are considered promising anode materials for lithium-ion batteries (LIBs) due to their low cost and high theoretical specific capacities. However, low conductivity and dissolution of lithium polysulfides during the reaction hamper their practical applications. Herein, we firstly synthesized N-doped carbon-coated Fe1-xS (Fe1-xS@NC) sheets through vacuum pyrolysis of the precursor Fe1-xS(en)0.5 (en = ethylenediamine). Then Fe1-xS@NC-rGO composites (rGO = reduced graphene oxide) were prepared in which the Fe1-xS@NC sheets were anchored on the rGO. The performance of the composites as an anode material for LIBs has been investigated. It is found that coating N-doped C on Fe1-xS surfaces can improve the surface conductivity and electrochemical kinetics of Fe1-xS, which is beneficial for the conversion between lithium polysulfides and Fe1-xS. In addition, the coated N-doped C on the Fe1-xS sheets can serve as a barrier to direct contact between the electrolyte and the material, reducing the dissolution of polysulfides and preventing the loss of active ingredients. More importantly, the double protection of the N-doped C layer and the flexible rGO substrate minimizes the structural damage caused by the cyclic expansion of Fe1-xS@NC-rGO. As expected, Fe1-xS@NC-rGO exhibits good rate performance with a reversible capacity of 939.5 mA h g-1 after 1690 cycles at a current density of 1.0 A g-1, along with outstanding charge and discharge performance and excellent long-term cycling stability. This work shows that the introduction of NC coating and the rGO matrix into Fe1-xS would synergistically enhance the performance of Fe1-xS for LIBs and highlights the effectiveness of the synthetic strategy for double carbon-based materials-protected sulfides in developing superior LIB electrodes.

Straightforward and Effective Surface Treatment of Silicon-Carbon Composite Anode Materials for Lithium Ion Battery

Straightforward and Effective Surface Treatment of Silicon-Carbon Composite Anode Materials for Lithium Ion Battery

Research progress in nanotechnology for enhanced silicon-based and iron-based anodes for lithium-ion batteries

Recent research has focused on making suitable anode materials for lithium-ion batteries and using nanotechnology to refine composite electrode materials with high reversible capacity and strong stability. However, much work remains to be done to develop these materials into commercially viable solutions. The anode materials must have high reversible capacity, a long lifetime, and the ability to accept and release lithium ions repeatedly. Nano-engineered composite anode materials based on silicon and iron have shown good promise but need improved electrochemical properties and longer effective lifetimes. This paper summarizes the performance characteristics of Si-based and Fe-based anodes and ways to improve their performance through nanoengineering.

Preparation of porous silicon composite anode material coated with open pore polymethyl acrylate and its electrochemical performance as a carbon source

Silicon (Si) is considered an ideal candidate for the next generation of lithium-ion batteries owing to its high specific capacity, low lithiation/delithiation potential, and abundance.