Anode Material For Li-ion Batteries Research Articles

Li₄Ti₅O₁₂/Graphene composite as an anode for Li-ion battery

Spinel structured Li4Ti5O12 (LTO) is one of the most promising candidate anode material for Li-ion battery known as zero strain material, it has poor intrinsic electronic properties. In order to enhance it, graphene was used as additive. The LTO and graphene composites were synthesized by reduction process of graphene oxide via hydrothermal treatment. Thepowders were characterized by X-Ray diffraction (XRD), Infrared spectroscopy (FT-IR).For the galvanostatic discharge and charge measurements were performed at roomtemperature against Li/Li+ metal electrode.

Very High Rate-Capable, Electrochemically Stable, Environmental Friendly and Safe Bi-Phase Na-Titanate Based Composite Anode for Na-Ion Batteries

Na-ion battery system lacks a safe, electrochemically stable, high ‘rate-capable’ and environmental/health friendly anode material. This is because the ‘workhorse’ anode material for Li-ion batteries, i.e., graphitic carbon, cannot reversibly host Na-ions in its lattice and hard carbon which is the widely explored anode for Na-ion batteries, possesses serious safety concerns and operational hazards [1-3]. In this scenario, the present work reports bi-phase Na-titanate based anode material, which is safe and environmental/health friendly, and which has the potential to exhibit excellent rate-capability and long-term cyclic stability, even at very high current densities. ‘Bi-phase NTO’, having Na2Ti3O7 and Na2Ti6O13 as primary and secondary phases, respectively, shows contributions from both the phases towards electrochemical Na-storage, as confirmed from operando synchrotron XRD studies, and is more electrochemically stable than phase pure Na2Ti3O7. Additionally, ‘bi-phase NTO’ also has safe and favourable Na-insertion/removal potential in terms of operation as anode. The reinforcement with functionalised multi-walled carbon nanotubes (MWCNTs) further improves the electrochemical performance of ‘bi-phase NTO’, bestowing it with excellent stability, stable ‘charge-averaged’ discharge/charge voltages and negligible impedance build-up over multiple cycles. Due to the presence of O-containing functional groups (facilitating favorable surface interaction with titanate) and the high aspect ratio, the MWCNTs were observed to uniformly cover the surface of the Na-titanate particles, almost ‘wrapping’ the same. This suppresses the occurrence of deleterious reactions at the Na-titanate/electrolyte interface and leads to excellent connectivity across the active particles. Accordingly, even at a very high current density corresponding to 50C, a 1st cycle reversible Na-storage capacity of >140 mAh g-1 (viz., negligible drop from capacities at lower C-rates) and capacity retentions of ~83%, ~65%, 58% after 100, 1000, 2000 cycles, respectively (see Fig. 1) were obtained with the as-developed ‘bi-phase NTO’/MWCNT-based electrodes; indicating the feasibility for long-term cycling even at very high current densities. A part of this work has been published as Pradeep et al., Electrochim. Acta 362 (2020) 137122, i.e., ref. [4] here. Keywords: Na-titanate; composite electrode; in-operando synchrotron X-ray diffraction; high rate performance; Carbon-based reinforcements; Na-ion battery Reference s : [1] P. Senguttuvan, M. R. Palacín, G. Rousse, V. Seznec and J.-M. Tarascon, Chem. Mater., 23, 4109 (2011).[2] A. Rudola, K. Saravanan, C. W. Mason, and P. Balaya, J. Mater. Chem., A 1, 2653 (2013).[3] W. Wang, C. Yu, Y. Liu, J. Hou, H. Zhu and S. Jiao, RSC Adv., 3, 1041 (2013).[4] A. Pradeep, B.S. Kumar, A. Kumar, V. Srihari, H.K. Poswal and A. Mukhopadhyay, Electrochim. Acta., 362, 137122 (2020). Figure 1

Silicon/Carbon Composite Anode Materials for Li-Ion Batteries from a Scalable and Continuous One-Step Gas Phase Process

Silicon as an anode material has been intensively studied in academia, yet issues correlated to the vast volume change still hinder application in industry greater than a few mass percent. Some approaches reported can suppress the rapid capacity fade, which is observed for pristine silicon powders. However, they are usually based on complex processes or involve expansive chemicals, making them less interesting for commercial applications. Our approach focuses on the production of a long-term stable, silicon-based composite material in a single, easy-to-scale manufacturing process in a free-space reactor.The newly developed composite consists of a silicon/carbon nanomaterial with a carbon-rich surface produced in a single-step gas phase process with production rates of already 100 – 500 g/h on the lab scale. Carbon is used as a composite component for two reasons: i) The incorporation of carbon in the range of 3-12 wt.% inhibits the formation of crystalline silicon within the silicon/carbon composites by disturbing the silicon-lattice, effectively preventing the formation of detrimental c-Li15Si4 phase during lithiation. ii) Furthermore, the carbon containing materials are less sensitive to oxidation and show enhanced cycling stability compared to pure silicon materials. By adjusting the process parameters, e.g. primary particle size d50,number can be tuned in the range of 40-120 nm. The electrochemical performance of the composite materials has been analyzed in half cells. For 75 wt.% active material electrodes, 90 % first cycle Coulombic efficiency and 75 % capacity retention after 200 cycles with an CCCV protocol at 0.5 C can be realized. Figure 1

2D Dumbbell Silicene as a High Storage Capacity and Fast Ion Diffusion Anode for Li-Ion Batteries.

First-principles calculations within DFT have been performed to investigate the use of a recently synthesized form of silicene, the dumbbell (DB) silicene as an anode material for Li-ion batteries (LiBs). The energetically most stable geometries for Li adsorption on DB silicene were investigated, and the energy barriers for Li-ion diffusion among the possible stable adsorption sites were calculated. We found that DB silicene can be lithiated up to a ratio of 1.05 Li per Si atom, resulting in a high storage capacity of 1002 mA h g-1 and an average open-circuit potential of 0.38 V, which makes DB silicene suitable for applications as an anode in LiBs. The energy barrier for Li-ion diffusion was calculated to be as low as 0.19 eV, suggesting that the Li ions can easily diffuse on the entire DB silicene surface, decreasing the time for the charge/discharge process of the LiBs. Our detailed investigations show that the most stable form of two-dimensional silicon has characteristic features suitable for application in high-performance LiBs.

Fabrication of Si/TiC–SiC/C composites as high-performance anode materials for Li-ion batteries

Si/TiC–SiC/C composites were prepared by solvothermal process, ball milling and subsequent calcination under Ar atmosphere. The microstructure of Si/TiC–SiC/C composites was characterized by X-ray diffraction, scanning electrons microscopy and transmission electron microscopy. Moreover, the relative contents of TiC and SiC phases in Si/TiC–SiC/C composites were determined by XRD Rietveld refinement and X-ray photoelectron spectroscopy, and their effects on the electrochemical properties of Si/TiC–SiC/C composites were further discussed. The results indicate that Si/TiC–SiC/C-0.33 composites with high relative content of TiC phase deliver capacity retentions of 98.0% after 50 cycles at 0.5 A g−1 and 79.5% after 150 cycles at 1 A g−1. The superior electrochemical performances should be attributed to the higher mechanical stability and better electronic conductivity of buffer matrix with higher TiC content.

Nano-Co3O4 anchored helical carbon nanofibers as an anode material for Li-ion batteries

Co 3 O 4 /HCNFs were firstly prepared successfully via a simple and inexpensive oil-bath method. Within the hybrid composite, the HCNFs and Co 3 O 4 show a synergistic effect to improve the specific capacity and cycling stability of Lithium-ion batteries. • A novel Co 3 O 4 /HCNFs anode composite was first introduced for lithium-ion batteries. • A simple two-step approach was successfully used to prepare the Co 3 O 4 /HCNFs composite material. • Co 3 O 4 /HCNFs composites make an obvious advantage as an anode material for lithium-ion batteries. In the current work, the Co 3 O 4 /helical carbon nanofibers (Co 3 O 4 /HCNFs) composite was successfully obtained by using a simple and inexpensive two-step method and applied as an anode material for lithium-ion batteries (LIBs). The results showed that Co 3 O 4 nanoparticles (the nanoparticle size of 10–20 nm) were anchored on the surface of helical carbon nanofibers. The Co 3 O 4 /HCNFs anode displays an excellent cyclability of 853 mAh/g after 200 cycles under the current density of 200 mA/g (327.7 %, 183.7 %, and 172.0 % higher than the pure HCNFs, pure Co 3 O 4 , and Co 3 O 4 -HCNFs respectively). The superior electrochemistry capability of the Co 3 O 4 /HCNFs composites are mainly thankful to the specific 3D helical structure of HCNFs, which can not only accommodate the volume expansion of nano-Co 3 O 4 during charge–discharge process, but also greatly enhance the conductivity of Co 3 O 4 . Therefore, this research provides a novel method to exploiting an excellent and stable anode material for enhanced LIBs.

Constructing angustifolia-like MoS2 on Ag nanowires as anode with enhanced diffusion kinetics for Li-ion batteries

The unfavorable rate capacities and cycling property are insurmountable problems for application of pure MoS2 anode in Li-ion batteries. In this regard, a brief methodology used in the synthesis of AgNWs@MoS2 is discussed. Emphasis is placed on the construction of a nanocomposite anode by which the cycling behavior and rate capability of MoS2 can be improved. As the 1D skeletons of Ag nanowires constitute fast conductive pathways and prevent volume expansion of pure MoS2 as charge/discharge process, enhancing the Li+ diffusion coefficient in electrode. The experimental results reveal interesting examples of AgNWs@MoS2 anode of admirable rate property and promising long-cycling appearance (310 mAh g−1 at 1 A g−1 after 1000 cycles). The scope of this research lies in providing a type of excellent anode material in Li-ion batteries.

Ag decorated porous Si structure as potential high-capacity anode material for Li-ion cells

• Sample HCSi was synthesized by MRR of silica powder and improved with Ag nPs. • Silver nanoparticles were deposited in different amounts to increase conductivity. • The kinetics of Li alloying was analysed by chronoamperometric responses CV and EIS. • Sample HCSi10highest intercalation intensity Cs of 3333 mAh/g. • This strategy offers a promising route to advances in anode material for Li-ion cells. Ag decorated honeycomb silicon structure (HCSi) was prepared by magnesiothermic reduction of the synthesized SiO 2 and investigated as a potential anode material for Li-ion batteries. In order to increase the conductivity of HCSi, Ag nanoparticles were deposited on HCSi in different amounts. The characterization of HCSi powder showed the mean particle size of ≈30–40 nm and BET surface area of 102.22 m 2 /g. Sample HCSi10, which had the highest Ag content, showed the highest conductivity of 1.379 × 10 3 S/cm and lower BET surface (34.04 m 2 /g) which is suitable for anode material. These three materials were investigated as anode material in Li-ion cells and their electrochemical properties were investigated by chronoamperometry, cyclic voltammetry and electrochemical impedance spectroscopy. The enhanced electrochemical performance of sample HCSi10 is attributed to the lowest impedance, highest intercalation intensity and current which results in specific capacity of 3333 mAh/g at 0.067 A/g, and 2400 mAh/g at 0.2 A/g.

Carbon assisted hollow nano-metal phosphide composite as anode material for high-performance lithium-ion batteries

• Hollow Ni 0.5 Co 0.5 P 2 /carbon were synthesized from metal organic framework microspheres. • The ratio of Ni/Co can be regulated in Ni 0.5 Co 0.5 P 2 /carbon composite. • The Ni 0.5 Co 0.5 P 2 /carbon composite exhibits excellent electrochemical performances. Nano-metal phosphides/carbon microspheres, Ni 0.5 Co 0.5 P 2 /carbon (NCP@C), with unique hollow structure were synthesized by solvothermal reaction and phosphorization treatment. When used as anode material for Li-ion batteries, NCP@C composites exhibit high reversible specific capacity (1370 mAh g −1 at 0.1 C), good rate performance and excellent cycling stability (826 and 703 mAh g −1 after 300 cycles at 0.2 and 0.5 C, respectively).

In-situ self-assembly robust defected graphene wrapped silicon/nanorod carbon for high-performance binder-free Li ion battery

• Utilization of evaporation-induced self-assembling method benefits to prepare the large scalable electrode film. • 3D conductive porous network provides voids for Si expansion and accelerates lithium ion transport. • The binder-free Si/NRC@DG stabilizes the capacity retention. • The Si/NRC@DG//LiFePO 4 full cell exhibits excellent electrochemical performance. High capacity silicon electrode with low cost is deemed as the promising anode material for the future Li-ion batteries with the replacement of graphite anode. In this work, robust defected graphene layers wrapped silicon/nanorod carbon (Si/NRC@DG) is synthesized through evaporation-induced self-assembly method for high lithium ion storage. Results show that the rapid conductive network formed by nanorods and defected graphene shorten the electron/lithium ion pathway to reach Si nanoparticles, enhancing the utilization. Meanwhile, the unique three-dimensional nano-architecture accommodates the large volumetric expansion of Si, immerses the electrolyte and facilitates efficient lithium ion diffusion. As a result, the so-synthesized Si/NRC@DG electrode exhibits a remarkable capacity of 669 mA h g −1 at 0.1 A g −1 after 100 cycles. Coupled with LiFePO 4 cathode, the assembled full cell is capable of offering an initial capacity of 126 mA h g −1 , providing opportunities for realizing high energy lithium ion batteries.

Bi@C fibre synthesized by electrostatic spinning as high-performance anode material for Li-ion batteries

Bi@C fibre synthesized by electrostatic spinning as high-performance anode material for Li-ion batteries

High Initial Coulombic Efficiency of SiO Enabled by Controlling SiO2 Matrix Crystallization.

SiO is a promising anode material for practical Li-ion batteries because it can achieve a much higher capacity than graphite and a better capacity retention than Si. However, SiO suffers from poor initial Coulombic efficiency (ICE). Here, we report on a fundamentally different approach to increase the low ICE of SiO while achieving high capacity and long-term cycle stability compared to previous approaches such as electrochemical/chemical pre-lithiation processes. To enhance the ICE, the long-range/short-range orders of amorphous SiO2 in SiO are increased by the chemical reaction of a small amount of LiOH·H2O even at a much lower temperature (900 °C) than the reported. The increased crystallization of SiO2 substantially reduces the irreversible electrochemical reaction of SiO. As a result, the Li-added SiO shows substantially increased ICE, ∼82.7%, which is one of the highest values. Furthermore, we demonstrate that controlling the crystallization of SiO can enable us to achieve high ICE, high reversible capacity, and superior capacity retention (∼100% at 1C rate for 100 cycles) in SiO simultaneously. The understanding and findings will pave the way to design high-capacity SiO with high ICE and long-term stability for practical high energy density Li batteries.

Titanium Diboride-Based Hierarchical Nanosheets as Anode Material for Li-Ion Batteries

Titanium Diboride-Based Hierarchical Nanosheets as Anode Material for Li-Ion Batteries

Metal-organic framework-derived mixed-phase anatase/rutile TiO2 towards boosted lithium storage: Surface engineering and design strategy through crystal phase transition

The design and construction of electrodes with surface and interface structures bring new opportunities for high-performance lithium storage properties. Herein, we present a simple synthesis method to fabricate surface-amorphized anatase/rutile mixed-phase truncated octahedral TiO2 (TO-AR) structures with oxygen vacancy derived from metal-organic framework (MOF) with a temperature-controlled phase transition. Compared with single-phase TiO2, the mixed-phase TO-AR electrode shows higher specific capacity and better rate performance. Systematic experimental studies and theoretical calculations demonstrate that the abundant interface between anatase and rutile induced by the crystallographic phase transition provides efficient high-capacity Li+ storage and enhanced charge-transfer kinetics. Meanwhile, the amorphous surface and higher oxygen vacancy concentration improve the surface-induced capacitive properties. These results provide new insights into improving the electrochemical performance of metal-organic framework-derived anode materials in Li-ion batteries.

Preparation of SiC-Coated Silicon Nanofiber/Graphite Composites as Anode Material for Li-Ion Batteries by the Chemical Vapor Deposition Method

Abstract Si material has huge lithium storage capacity, but its huge volume changes during charging and discharging making it difficult to use. However, by using nano-sizing Si material and building a coating structure can effectively reduce the capacity reduction caused by the expansion of the Si material. In our experiment, dichlorodimethylsilane was used as the silicon source and carbon source for the deposition of silicon nanofibers and SiC-coated on a spherical graphite substrate, and then the SiC cladding was deposited without changing the temperature and silicon source, and only the C to H ratio in the atmosphere was controlled to build the cladding layer. In our experiment, silicon nanofibers were deposited on graphite surfaces using dichlorodimethylsilane as the silicon source, followed by SiC cladding on the surface of the Si/G composites using dichlorodimethylsilane as the silicon source and carbon source. The end product was controlled by controlling only the C to H ratio in the atmosphere at the same temperature. The preparation of SiC@Si/G composites with silicon nanofibers and cladding structures by a single CVD process and single raw materials. The material has a silicon nanofiber structure and SiC coating structure. The presence of silicon is effective in providing very high capacity and the presence of the SiC layer is effective in improving the capacity retention of the composite material for increasing the Coulomb efficiency of the material. At a current density of 100 mA h g−1, the material has a reversible capacity of 647.3 mA h g−1 at the first cycle. After 100 cycles, it has a 76.2% retention rate. The electrodes can be extremely stable after cycling without significant swelling.

Highly stable Fe2O3@Fe3O4@FeCO3 heterostructure anchored on graphene as the enhanced electrochemical performance of Li-ion battery anodes

Fe-based oxides have received tremendous attention owing to its high capacity, low cost, controllable morphology, and immense natural reserves. However, their poor cycle stability hinders practical application. In the present paper, Fe2O3@Fe3O4@FeCO3/reduced graphene oxide (3-Fe/rGO) composite was synthesized by green and simple strategy. The particle size of 3-Fe heterostructure is reduced and dispersed evenly on the rGO surface. The 3-Fe/rGO composite exhibits excellent electrochemical performance as anode material in Li-ion batteries. The specific discharge capacities of 3-Fe/rGO composite are 868.7 mA g−1 after 200 cycles at 200 mA g−1 and 578.9 mA g−1 after 500 cycles at 2 A/g. The outstanding electrochemical properties arise from the effective synergy existing between FeCO3, Fe3O4, Fe2O3, and rGO. Considering the charge transfer and Li+ diffusion, 3-Fe/rGO composite shows excellent properties, indicating that the typical structure and excellent properties of rGO can aid in the coating and buffering of the expansion of 3-Fe heterostructure during the Li+ extraction and insertion processes, reducing the loss of irreversible capacity. Moreover, the conductivity of the electrode is significantly improved. This is an already established method to improve the electrochemical performance of Fe-based oxides, but the present work has added new dimensions to it.

Li2Zn0.9Al0.1Ti3O8/C as a High-Property Anode Material for Li-Ion Batteries

Li2Zn0.9Al0.1Ti3O8/C as a High-Property Anode Material for Li-Ion Batteries

Sb Nanoparticles Embedded in the N-Doped Carbon Fibers as Binder-Free Anode for Flexible Li-Ion Batteries.

Antimony (Sb) is considered a promising anode for Li-ion batteries (LIBs) because of its high theoretical specific capacity and safe Li-ion insertion potential; however, the LIBs suffer from dramatic volume variation. The volume expansion results in unstable electrode/electrolyte interphase and active material exfoliation during lithiation and delithiation processes. Designing flexible free-standing electrodes can effectively inhibit the exfoliation of the electrode materials from the current collector. However, the generally adopted methods for preparing flexible free-standing electrodes are complex and high cost. To address these issues, we report the synthesis of a unique Sb nanoparticle@N-doped porous carbon fiber structure as a free-standing electrode via an electrospinning method and surface passivation. Such a hierarchical structure possesses a robust framework with rich voids and a stable solid electrolyte interphase (SEI) film, which can well accommodate the mechanical strain and avoid electrode cracks and pulverization during lithiation/delithiation processes. When evaluated as an anode for LIBs, the as-prepared nanoarchitectures exhibited a high initial reversible capacity (675 mAh g−1) and good cyclability (480 mAh g−1 after 300 cycles at a current density of 400 mA g−1), along with a superior rate capability (420 mA h g−1 at 1 A g−1). This work could offer a simple, effective, and efficient approach to improve flexible and free-standing alloy-based anode materials for high performance Li-ion batteries.

Navel orange peel-derived hard carbons as high performance anode materials of Na and Li-ion batteries

Deriving carbon electrode materials from biomass resources has been the ongoing research interest for sustainable development of high performance electrochemical energy storage devices. Herein, navel orange peel is used as an abundant raw material to prepare hard carbon anodes for Na and Li-ion batteries through a two-step process. The hydrothermal treatment effectively decomposes the biomass into uniform precursor, while the following high temperature carbonization results in fine hard carbon particles. The hard carbon carbonized at 1300 °C exhibits the best Na ion storage performance including a high initial reversible capacity of 337 mAh g−1 at 0.1 A g−1 and a high remaining capacity of 234 mAh g−1 after 500 cycles at 0.5 A g−1, which can be explained by its featured structure favoring the adsorption-intercalation/filling model. The hard carbon pyrolized at 1100 °C displays a much higher reversible capacity of 428 mAh g−1 than many other biomass-derived hard carbon anodes together with a robust cycle stability. These outstanding Na and Li ion storage properties convincingly demonstrate that the two-step process as well as the abundant navel orange peel resource can provide a potential solution to sustainable development of high performance hard carbon anode materials for Na and Li-ion batteries.

Influence of the SEI Formation on the Stability and Lithium Diffusion in Si Electrodes.

Silicon (Si) is an attractive anode material for Li-ion batteries (LIBs) due to its high theoretical specific capacity. However, the solid–electrolyte interphase (SEI) formation, caused by liquid electrolyte decomposition, often befalls Si electrodes. The SEI layer is less Li-ion conductive, which would significantly inhibit Li-ion transport and delay the reaction kinetics. Understanding the interaction between the SEI components and Li-ion diffusion is crucial for further improving the cycling performance of Si. Herein, different liquid electrolytes are applied to investigate the induced SEI components, structures, and their role in Li-ion transport. It is found that Si electrodes exhibit higher discharge capacities in LiClO4-based electrolytes than in LiPF6-based electrolytes. This behavior suggests that a denser and more conductive SEI layer is formed in LiClO4-based electrolytes. In addition, a coating of a Li3PO4 artificial SEI layer on Si suppresses the formation of natural SEI formation, leading to higher capacity retentions. Furthermore, galvanostatic intermittent titration technique (GITT) measurements are applied to calculate Li-ion diffusion coefficients, which are found in the range of 10–23–10–19 m2/s.