Anode For Lithium-ion Batteries Research Articles

CoO nanocrystals dispersed in N-doped carbon networks as enhanced anode for lithium storage

CoO emerges as a promising anode material for lithium-ion batteries (LIBs) because of high theoretical specific capacity and rich resource. However, its practical application is impeded by significant volume expansion and poor electrical conductivity during the charging and discharging cycles. Herein, we construct a nanocomposite of CoO nanocrystals and N-doped carbon serving as an enhanced anode for LIBs by a facile strategy. In the nanocomposite, CoO nanocrystals with average size of 60 nm uniformly were dispersed in N-doped carbon networks. The synergy effects of CoO nanocrystals and N-doped carbon networks can extremely enhance electronic conductivity, relieve volume expansion, and effectively protect CoO nanocrystals from aggregating. Hence, the composite anode delivers large reversible capacity (1190 mAh g−1 at 0.3 A g−1 after 100 cycles), remarkable rate capability (592 mAh g−1 at 5 A g−1), and long cycling ability. This offers a simple approach for designing high-performance anodes for LIBs.

Three-dimensional CNTs boosting the conductive confinement structure of silicon/carbon anodes in lithium-ion batteries

In this study, a surface functionalization strategy was proposed to involve carbon nanotubes and silicon nanoparticles encapsulated within carbon derived from a zeolite imidazole framework (ZIF-67). Multidimensional interconnected carbon nanotubes bolster the structural stability and facilitate ion/electron transfer within silicon/carbon composites. Silicon nanoparticles were successfully encapsulated in ZIF-67-derived carbon shells, with carbon nanotubes effectively transferring interfacial stress between silicon and carbon shell during lithiation, where ZIF-67-derived carbon reduces the volume expansion in silicon anodes. As a consequence, the outstanding cycle life and rate performance were demonstrated in the silicon/carbon composites. The specific capacity was maintained at 660 mAh g-1 over 200 cycles at 1 A g-1. The in-situ construction of this conductive confinement structure based on three-dimensional carbon nanotubes offers a promising design approach for advancing silicon/carbon anode technologies.

Elucidation on Abnormal Capacity Increase in SiO2@C Core-Shell Nanospheres Anode for Lithium-Ion Battery.

An abnormal capacity increase stage has been observed in nanostructured SiO2 after the initial capacity drop stage. To investigate the Li+ storage kinetic mechanism for each stage, SiO2@C core-shell nanospheres with a total diameter of ∼108 to 170 nm but an adjustable C shell thickness of ∼4 to 31 nm have been fabricated. First, the existence form and specific content of SiO2 nanoparticles with a size of ∼6-10 nm, which are embedded in the outer C shell of SiO2@C core-shell nanospheres, were confirmed by SEM, TEM, BET, and TGA, respectively. It was found that the initial stage for capacity drop happens at 15-43 cycles and is followed by an enhancement stage, which presents an increase of ∼120 to 180% in capacity relative to the lowest capacity value during cycling. Among them, the sample of P-1 with a diameter of 109 nm for the SiO2 core and thickness of 31 nm for the C shell delivers the highest specific capacity of 1060 mAh/g at 100 mA/g and a capacity increase rate of ∼180% through 300 cycles. XPS analysis for the delithiation process indicates that the capacity drop and increase stage involves the partial oxidation of Li silicate, which is correlated to the formation of Li2Si2O5. Our study can be used to explain the mechanism of the abnormal capacity increase phenomenon for the SiO2 anode and provide a high-capacity anode material for LIB application.

Novel binder-free vanadium-based molten salt (NMPV) with low-cost as anode materials of lithium-ion batteries

Molten salt NMPV material is synthesised using a one-step method and applied to binder-free anodes for lithium-ion batteries (LIBs). In this work, simple, low-cost and highly active coordination molten salt electrode materials (NMPV and NMPV-C) were prepared, which overcame the drawbacks of cumbersome and costly preparation of the existing electrode materials. NMPV is formed by the lone pair of electrons of N-methyl pyrrolidone (NMP) molecules coordinated with vanadium ion. The synergistic effect produced by these two and the excellent electrical conductivity and electrochemical properties of the molten salt material itself exhibits satisfactory lithium storage results. The discharge capacities of NMPV-C and NMPV in the second discharge cycle are 669 and 345 mAh g−1, respectively. After 100 cycles, the capacity is maintained at 923 and 549 mAh g−1, respectively. And the capacity retention is 137.97 % and 159.13 %, respectively. In addition, the NMPV-C electrode maintains a stable reversible capacity of 450 mAh g−1 at 2000 mAh g−1 after 220 cycles. Density-functional theory (DFT) calculations revealed that Li+ is more likely to attack H on methyl nitrogen, which is the optimal reaction site for NMPV since the lone pair of electrons of N effectively stabilises the carbon cation after the reaction of Li with H.

A Review of Nanocarbon-Based Anode Materials for Lithium-Ion Batteries

Renewable and non-renewable energy harvesting and its storage are important components of our everyday economic processes. Lithium-ion batteries (LIBs), with their rechargeable features, high open-circuit voltage, and potential large energy capacities, are one of the ideal alternatives for addressing that endeavor. Despite their widespread use, improving LIBs’ performance, such as increasing energy density demand, stability, and safety, remains a significant problem. The anode is an important component in LIBs and determines battery performance. To achieve high-performance batteries, anode subsystems must have a high capacity for ion intercalation/adsorption, high efficiency during charging and discharging operations, minimal reactivity to the electrolyte, excellent cyclability, and non-toxic operation. Group IV elements (Si, Ge, and Sn), transition-metal oxides, nitrides, sulfides, and transition-metal carbonates have all been tested as LIB anode materials. However, these materials have low rate capability due to weak conductivity, dismal cyclability, and fast capacity fading owing to large volume expansion and severe electrode collapse during the cycle operations. Contrarily, carbon nanostructures (1D, 2D, and 3D) have the potential to be employed as anode materials for LIBs due to their large buffer space and Li-ion conductivity. However, their capacity is limited. Blending these two material types to create a conductive and flexible carbon supporting nanocomposite framework as an anode material for LIBs is regarded as one of the most beneficial techniques for improving stability, conductivity, and capacity. This review begins with a quick overview of LIB operations and performance measurement indexes. It then examines the recently reported synthesis methods of carbon-based nanostructured materials and the effects of their properties on high-performance anode materials for LIBs. These include composites made of 1D, 2D, and 3D nanocarbon structures and much higher Li storage-capacity nanostructured compounds (metals, transitional metal oxides, transition-metal sulfides, and other inorganic materials). The strategies employed to improve anode performance by leveraging the intrinsic features of individual constituents and their structural designs are examined. The review concludes with a summary and an outlook for future advancements in this research field.

Two-dimensional BC12 as an ultra-high performance anode material for lithium-ion batteries

With the gradual development of renewable energy, search for high-performance energy storage materials as anodes for lithium-ion batteries (LIBs) has become urgent. Two-dimensional (2D) materials are considered as candidates for anode materials due to their unique structure and physicochemical properties. Based on first-principles calculations, we propose a 2D material, BC12 monolayer, as an excellent anode for LIBs. BC12 exhibits outstanding dynamic, mechanical, and thermal stability. In addition, BC12 monolayers show not only remarkably high storage capacity (2767.57 mA h g−1) but also low diffusion barrier energy (0.175 eV) and appropriate open circuit voltage (0.3 V). A small volume expansion (0.38%) is also observed during the lithiation process. Furthermore, we undertake a comprehensive analysis on the impact of carbon vacancy in BC12. The presence of carbon vacancy makes the adsorption and diffusion of Li relatively weak, which should be carefully handled in the experimental synthesis process. The above-mentioned investigation offers valuable insights and guidance for the future development and application of 2D anode materials in metal-ion batteries.

Innovative Tin and hard carbon architecture for enhanced stability in lithium-ion battery anodes

Tin (Sn), with a theoretical capacity of 994 mAh g-1, is a promising anode material for lithium-ion batteries (LIBs). However, fundamental limitations like large volume expansion during charge-discharge cycle and confined electronic conductivity limit its practical utility. Here, we report a new material design and manufacturing method of LIB anodes using Sn and Hard Carbon (HC) architecture, which is produced by Physical Vapor Deposition (PVD). A bilayer HC/Sn anode structure is deposited on a carbon/copper sheet as a function of deposition time, temperature, and substrate heat treatment. The developed anodes are used to make cells with a lithium-ion electrolyte using a specific fabrication process. The morphology, atomic structure, conductivity, and electrochemical performance of the developed HC/Sn anodes are studied with SEM, TEM, XPS, and electrochemical techniques. At a discharge rate of 0.1C, the Snheated + HC anode performs exceptionally well, offering a capacity of 763 mAh g-1. It is noteworthy that it achieves a capacity of 342 mAh g-1 when fast charging at 5C, demonstrating exceptional rate capability. The Snheated + HC anode maintains >97 % Coulombic efficiency of its capacity after 3000 cycles at a rate of 0.1C after 3000 cycles 730.5 mAh g-1 recorded, demonstrating an impressive cycle life. The novel material design approach of the Snheated + HC anode, which has a multi-layered structure and HC acting as a barrier against volumetric expansion and improving electronic conductivity during battery cycling, is perceived as influential in uplifting anode's performance.

Small‐Molecule Polycyclic Aromatic Hydrocarbons as Exceptional Long‐Cycle‐Life Li‐Ion Battery Anode Materials

The growing demand for cost‐effective and sustainable energy‐storage solutions has spurred interest in novel anode materials for lithium‐ion batteries (LIBs). In this study, the potential of small‐molecule polycyclic aromatic hydrocarbons (SMPAHs) as promising candidates for LIB anodes is explored. Through a comprehensive experimental approach involving electrode fabrication, material characterization, and electrochemical testing, the electrochemical performance of SMPAHs, including naphthalene, biphenyl, 9,9‐dimethylfluorene, phenanthrene, p‐terphenyl, and pyrene (Py), is thoroughly investigated. In the results, the impressive cycle stability, high specific capacity, and excellent rate capability of the SMPAH electrode are revealed. Additionally, a direct contact prelithiation strategy is implemented to enhance the initial Coulombic efficiency (ICE) of SMPAH anodes, yielding significant improvements in the ICE and cycle stability. Computational simulations provide valuable insights into the electrochemical behavior and lithium‐storage mechanisms of SMPAHs, confirming their potential as effective anode materials. The simulations reveal favorable lithium adsorption sites, the predominant storage mechanisms, and the dissolution mechanism of Py through computational calculations. Overall, in this study, the promise of SMPAHs is highlighted as sustainable anode materials for LIBs, advancing energy‐storage technologies toward a greener future.

Unveiling the Interplay Between Silicon and Graphite in Composite Anodes for Lithium-Ion Batteries.

Si provides an effective approach to achieving high-energy batteries owing to its high energy density and abundance. However, the poor stability of Si requires buffering with graphite particles when used as anodes. Currently, commercial lithium-ion batteries with Si/graphite composite anodes can provide a high energy density and are expected to replace traditional graphite-based batteries. The different lithium storage properties of Si and graphite lead to different degrees of lithiation and chemical environments for this composite anode, which significantly affects the performance of batteries. Herein, the interplay between Si and graphite in mechanically mixed Si/graphite composite anodes is emphasized, which alters the lithiation sequence of the active materials and thus the cycling performance of the battery. Furthermore, performance optimization can be achieved by changing the intrinsic properties of the active materials and external operating conditions, which are summarized and explained in detail. The investigation of the interplay based on Si/graphite composite anodes lays the foundation for developing long-life and high-energy batteries. The abovementioned experimental methods provide logical guidance for future research on composite electrodes with multiple active materials.

Flexible electrospun carbon nanofibers - nickel disulfide@carbon nanofibers - carbon nanofibers sandwich structure as binder-free anode for high performance lithium-ion batteries

People have recently shown increasing interest in wearable and flexible electronics. Due to their high electrical conductivity and flexibility, carbon nanofibers can be utilized for various flexible applications. However, pure carbon nanofibers have low capacity, which makes it challenging to achieve high capacity for flexible applications. Herein, sandwich-like nanofibers - nickel disulfide@carbon nanofibers - carbon nanofibers are obtained through a multi-step electrospinning process to serve as a flexible binder-free anode for lithium-ion batteries. This strategy stabilizes the structure well with two layers of carbon nanofibers, effectively accelerating the Li+ diffusion and promoting the electrolyte infiltration. Accordingly, the electrode exhibits a discharge capacity of 551.8 mAh g-1 at 0.1 A g-1 after 100 cycles and achieves a discharge capacity of 523.8 mAh g-1 at 1 A g-1 after 1000 cycles, demonstrating excellent cyclic stability and high capacity for Li+ storage. The kinetic analysis also reveals that the sandwich structure provides a higher capacity contribution. This work introduces a novel approach for creating flexible binder-free anodes with high performance, effectively expanding the application of sulfides through electrospinning.

(Sn, Ti)O2 Solid Solution: Mechanically Reinforced SnO2@TiO2@C Anode for Cycle Stability of Lithium-ion Batteries

Among the various materials investigated for use as anodes in lithium-ion batteries (LIBs), SnO2 faces the significant challenge of substantial volume expansion, severely limiting its practical applications. To address this issue, this paper uses a simple co-precipitation method to synthesize ultrafine SnO2 and TiO2 encapsulated in cross-linked porous carbon (SnO2@TiO2@C), in which SnO2 acts as the primary active material. At the same time, TiO2 functions as a mechanical buffer to mitigate the large volume expansion of SnO2. Additionally, developing (Sn, Ti)O2 solid solution at the interface between TiO2 and SnO2 significantly enhances the bonding between these components, effectively preventing their separation. The cross-linked carbon enhances the conductivity of the SnO2@TiO2@C. The combination of TiO2 and cross-linked carbon produces a synergistic effect that enhances the remarkable cycling performance of SnO2@TiO2@C (769.1 mAh/g after 100 cycles at 0.2 A/g), impressive rate performance (422.3 mAh/g at a discharge rate of 10 A/g) and extended cycle life (403.6 mAh/g after 2,000 cycles at 5 A/g). Moreover, this study examined how various ratios of SnO2 and TiO2 influence the electrochemical performance of SnO2@TiO2@C.

Towards practical Li-ion full batteries with glass anodes

Vanadium (V)-based glasses have recently garnered considerable attention as promising anode materials for lithium-ion batteries (LIBs) due to their abundance of Li+ storage sites, neglectable volume expansion upon lithiation/delithiation, and ease of preparation. However, the inherently low electrical conductivity and relatively low energy density of V-based glass anodes hinder its application in full LIBs. In this work, we tackled this challenge by optimizing the chemical composition of the V-based glass anode to achieve high-performance half and full batteries. We investigated the impact of partially substituting B2O3 for P2O5 in 50V2O5-(50-x)P2O5-xB2O3 (mol%) (VPB) glass series on its structure and electrochemical performances. The glass with 30mol% B2O3 (VPB30 glass) was found to deliver the highest electronic conductivity, an enhanced reversible capacity of 470mAh g−1 at 1Ag−1 after 500 cycles, and excellent rate capability. The optimized performances were ascribed to the boosted lithium-ion diffusivity and the increased lithium storage sites. We assembled a full cell by coupling a VPB30 glass anode with a LiCoO2 cathode to test its cycling performance. The VPB30//LiCoO2 cell exhibits the required power density, and hence, high practicality. Our work implied the practical application of glass anodes in high-performance LIBs.

In situ multilevel covalent crosslinking binder with high ionic conductivity for high-performance Si anodes

Silicon (Si) anode has emerged as a promising material for high-energy-density lithium-ion batteries (LIBs), thanks to its high theoretical capacity. However, the commercial application of Si anodes is hindered by inadequate cycling performance and poor interfacial stability, stemming from unfavorable stress conditions. In this study, a multiple crosslinking binder with high ionic conductivity is proposed combining high mechanical strength and high adhesion to current collector and active Si particles by coupling poly(acrylic acid), polyvinyl alcohol, and polyethylene glycol. The designed polymer binder not only efficiently dissipates the inner stress with its multiple crosslinked networks, but also establishes a fast lithium-ion conduction pathway to facilitate the electrode reaction kinetic. The resultant Si anode using the designed binder exhibits significantly improved cycling stability and superior rate performance. This work presents a straightforward yet highly effective method to alleviate the detrimental stress incurred by high-capacity anodes in high-energy LIBs.

The future of carbon anodes for lithium-ion batteries: The rational regulation of graphite interphase

The future of carbon anodes for lithium-ion batteries: The rational regulation of graphite interphase

Effective improvement of lithium-ion battery anode performance of Ti3C2 by alkali metal ion treatment strategy

MXene has emerged as a promising electrochemical energy storage material due to modifiable layered structure and good electrical conductivity. However, its lamellar stacking has severely limited the electrochemical performance during charging and discharging. Herein, the Li-treated Ti3C2 and Na-treated Ti3C2 nanocomposites are prepared by hydrothermal treatment. Li-treated Ti3C2 exhibits the largest discharge specific capacity, with an initial capacity of 551.5 mA h/g at a rate of 0.1 A/g, which is 81.3 mA h/g higher than Na-treated Ti3C2. After 200 cycles, the Li-Ti3C2 possesses a final capacity of 321.1 mA h/g, better than Na-Ti3C2 (151.7 mA h/g) and Ti3C2 (119.3 mA h/g). The Li-Ti3C2 shows superior cycling performance at a high rate of 2 A/g and a capacity retention rate of 84 % after 1000 cycles. During hydrothermal treatment, the in situ generated TiO2 plays a crucial role in the targeted introduction of metal ions. Density functional theory (DFT) calculations verify that LiTiO2 phase in Li-treated Ti3C2 possesses low band gap and lowest Li migration barrier. The synergy of these factors leads to the improved electrochemical performance of Li-treated Ti3C2. This work provides novel design strategies for developing MXene materials as high performance lithium-ion batteries.

Enhancing lithium-storage properties through amino functionalization in two-dimensional lamellar carbon-supported mesoporous SiO2 nanospheres

Currently, common two-dimensional (2D) carbon materials composited with Si-based materials as anode for lithium-ion batteries exhibit excellent electrochemical properties. In this study, we describe the one-step synthesis of amino-functionalized mesoporous silica (SiO2) nanospheres through self-assembly. Morphology modulation and amino group grafting were performed simultaneously without secondary modification. Using tartaric acid and melamine as dual carbon sources, the 2D lamellar structure was constructed using the dehydration condensation reaction, with the mesoporous SiO2 nanospheres uniformly intercalated within the carbon sheets. The composites were securely bonded by chemical bonding, effectively addressing the issue of structural collapse often encountered in silica–carbon composites. Ultimately, the lamellar SiO2@NC composite exhibited stable capacity of 539.5 mAh g−1 after 500 cycles at 1 A g−1. This strategy is simple and effective, compared to the complex processes typically associated with 2D carbon materials synthesis, and can be potentially extended to applications in catalysis, adsorption, and separation within diverse fields.

Multi-dimensional carbon modification strategy for lithium-ion battery anodes: Carbon-covered TiP2O7 supported by 3D carbon skeleton

Carbon coating is a beneficial method for improving surface capacitive behavior, electron transfer kinetics and cyclic stability of three-dimensional lattice lithium-embedded anode materials. Herein, we adopt one-step pyrolysis to achieve carbon-covered TiP2O7 supported by a three-dimensional carbon skeleton utilizing phytic acid and glucose as carbon sources. The two-dimensional amorphous carbon layer on TiP2O7 surface improves the initial Coulombic efficiency and rate capacity by inhibiting the irreversible embedding of lithium ions and reducing the interfacial charge transfer impedance. The three-dimensional carbon skeleton not only forms a conductive pathway between the carbon-covered TiP2O7, but also its large specific surface area, randomly oriented and defective carbon layer provide extra lithium storage sites and capacitive contribution. In addition, the specific capacity of the TiP2O7/C composite is still as high as 314.5 mA h g−1 after 1000 cycles at 1 A g−1. A TiP2O7/C//LiFePO4 full cell delivers a high energy density of 273.96 Wh kg−1 at 0.153 kW kg−1, and retains 114.43 Wh kg−1 even at the power density of 4.086 kW kg−1. The multi-dimensional carbon modification strategy has improved the electrochemical performance of TiP2O7-based anode materials, providing a model for synthesizing other high-performance anode materials.

Comparative Investigation of Water-Based CMC and LA133 Binders for CuO Anodes in High-Performance Lithium-Ion Batteries.

Transition metal oxides are considered to be highly promising anode materials for high-energy lithium-ion batteries. While carbon matrices have demonstrated effectiveness in enhancing the electrical conductivity and accommodating the volume expansion of transition metal oxide-based anode materials in lithium-ion batteries (LIBs), achieving an optimized utilization ratio remains a challenging obstacle. In this investigation, we have devised a straightforward synthesis approach to fabricate CuO nano powder integrated with carbon matrix. We found that with the use of a sodium carboxymethyl cellulose (CMC) based binder and fluoroethylene carbonate additives, this anode exhibits enhanced performance compared to acrylonitrile multi-copolymer binder (LA133) based electrodes. CuO@CMC electrodes reveal a notable capacity ~1100 mA h g-1 at 100 mA g-1 following 170 cycles, and exhibit prolonged cycling stability, with a capacity of 450 mA h g-1 at current density 300 mA g-1 over 500 cycles. Furthermore, they demonstrated outstanding rate performance and reduced charge transfer resistance. This study offers a viable approach for fabricating electrode materials for next-generation, high energy storage devices.

Stress-Relieving Carboxylated Polythiophene/Single-Walled Carbon Nanotube Conductive Layer for Stable Silicon Microparticle Anodes in Lithium-Ion Batteries.

Stress-relieving and electrically conductive single-walled carbon nanotubes (SWNTs) and conjugated polymer, poly[3-(potassium-4-butanoate)thiophene] (PPBT), wrapped silicon microparticles (Si MPs) have been developed as a composite active material to overcome technical challenges such as intrinsically low electrical conductivity, low initial Coulombic efficiency, and stress-induced fracture due to severe volume changes of Si-based anodes for lithium-ion batteries (LIBs). The PPBT/SWNT protective layer surrounding the surface of the microparticles physically limits volume changes and inhibits continuous solid electrolyte interphase (SEI) layer formation that leads to severe pulverization and capacity loss during cycling, thereby maintaining electrode integrity. PPBT/SWNT-coated Si MP anodes exhibited high initial Coulombic efficiency (85%) and stable capacity retention (0.027% decay per cycle) with a reversible capacity of 1894 mA h g-1 after 300 cycles at a current density of 2 A g-1, 3.3 times higher than pristine Si MP anodes. The stress relaxation and underlying mechanism associated with the incorporation of the PPBT/SWNT layer were interpreted by quasi-deterministic and quantitative stress analyses of SWNTs through in situ Raman spectroscopy. PPBT/SWNT@Si MP anodes can maintain reversible stress recovery and 45% less variation in tensile stress compared with SWNT@Si MP anodes during cycling. The results verify the benefits of stress relaxation via a protective capping layer and present an efficient strategy to achieve long cycle life for Si-based anodes for next-generation LIBs.

Effect of Sulfur Modification on Structural and Electrochemical Performance of Pitch-Based Carbon Materials for Lithium/Sodium Ion Batteries.

Coal tar pitch (CTP) has become an ideal choice in the preparation of anode precursors for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) because of its abundant carbon content, competitive pricing and adjustable structure properties. In this paper, sulfurized pitch-based carbon (SPC-800) was obtained by allowing CTP to react with sulfur at 350 °C and subsequently achieve carbonization at 800 °C. SPC-800 was more disordered and had a larger layer spacing than carbonized CTP (PC-800). Upon utilization as an anode for LIBs, SPC-800 possessed a higher reversible specific capacity (478.1 mAh g-1 at 0.1 A g-1), while utilization in SIBs displayed a capacity of 220.9 mAh g-1 at 20 mA g-1. This work is an important guide to the design of high-performance anodes suitable for use with both LIBs and SIBs.