Anode For Lithium-ion Batteries Research Articles

Overlooked challenges of interfacial chemistry upon developing high energy density silicon anodes for lithium-ion batteries

Evaluation of silicon (Si) anode performance by the assembled Si||Li half-cells is the primary approach in the development of high-energy-density lithium-ion batteries (LIBs). However, most studies focus solely on the variations of Si anode, the stability of electrolyte on the lithium (Li)-metal counter electrode has been overlooked. Herein, we discovered that the acquired cell performance not only depends on the Li+ (de-)solvation behaviors on the Si anode surface but also was affected significantly by the lithiation overpotential caused by the side reactions on the Li electrode. It is significant to identify this point, as these influences of electrolyte decomposition on the Li electrode have been previously regarded as an integral part of side reactions on the Si anode. We proposed a new perspective of the electrolyte solvation structure and electrode interfacial model to unravel the interfacial behaviors on the Si and Li electrodes respectively. The identified differences in the Li+ solvation and (de-)solvation behaviors not only provide reasons for the varied electrolyte stability in different electrolytes but also interpret the superior performance in tetrahydrofuran (THF)-based electrolytes. This study underscores the importance of understanding electrolyte behavior at the interfaces of individual electrodes to discern the reliability of electrode performance and also introduce a novel principle for designing superior electrolytes for high-energy-density LIBs.

Remarkable performance of Co3O4 anode coated with hard-soft carbon 2D nanosheets prepared from single pavement petroleum asphalt precursor

Incorporating extraneous carbonaceous materials to coat transitional metal oxide (TMO) anodes emerges as a viable strategy to mitigate the pulverization of TMO anode during Li-ion insertion/extraction processes. Herein, hard-soft carbon coated Co3O4 (HC-SC@Co3O4) composites were synthesized by employing a facile NaCl-mediated pyrolysis with Co(NO3)2·6 H2O as the oxide precursor and pavement petroleum asphalt as the single hard-soft carbon source. Microscopic structure characterizations revealed that HC-SC@Co3O4 exhibited a core-shell structure with a fluffy nanoflower-like S/O co-doped carbon shell. Benefiting from its distinctive coating structure, the HC-SC@Co3O4 anode demonstrated remarkable cycling stability and significant initial coulombic efficiency (ICE) of 71 %, after 150 cycles at 100 mA g−1, it still maintained a capacity of 742 mAh g−1. Moreover, introduction of soft carbon delivered outstanding rate capability upon HC-SC@Co3O4 anode, evidenced by discharge capacities of 1108 and 571 mA h g−1 at 100 and 1000 mA g−1, respectively. This study not only presents the potential to effectively solve the challenge of TMO anodes in lithium-ion batteries (LIBs), but also introduces an economically and environmentally approach for the efficient utilization of pavement petroleum asphalt.

Sulfur-doped silicon oxycarbide by facile pyrolysis process as an outstanding stable performance lithium-ion battery anode.

Silicon oxycarbide (SiOC) is drawing significant attention as a potential anode material for lithium-ion batteries due to its remarkable cycle life and the distinctive Si-O-C hybrid bonding within its structure. However, a notable drawback of SiOC-based electrodes is their poor electrical conductivity. In this study, we synthesized sulfur-doped silicon oxycarbide (S-SiOC) via facile one-pot pyrolysis from a mixture of commercial silicone oil with 1-dodecanethiol. Upon testing the S-SiOC electrode materials, we observed significant attributes, including an outstanding specific capacity (650 mA h g-1 at 1 A g-1), exceptional capacity retention (89.2% after 2000 cycles at 1 A g-1), and substantial potential for high mass loading of active materials (up to 2.2 mg cm-2). Sulfur doping led to enhanced diffusivity of lithium ions, as investigated through cyclic voltammetry (CV) and galvanostatic intermittent titration technique (GITT) tests. Consequently, this sulfur-doped silicon oxycarbide, exhibiting excellent electrochemical performance, holds promising potential as an anode material for lithium-ion batteries.

(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 2000 cycles at 5 A/g). Moreover, this study examined how various ratios of SnO2 and TiO2 influence the electrochemical performance of SnO2@TiO2@C.

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.

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.

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.

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.

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.

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.

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.

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

Oxygen vacancy modulated Ti2Nb10O29 anodes for high-rate lithium storage

Ti2Nb10O29 (TNO) is a prospective anode for lithium-ion batteries (LIBs) because of its high theoretical capacity, high energy density, and safer operating voltage. However, the lower conductivity and slower lithium-ion diffusion characteristic lead to performance degradation and accelerated capacity degradation. In this work, we developed a novel and simple urea-assisted heat treatment method to enrich oxygen vacancies in TNO anodes. Oxygen vacancy introduction leads to the formation of Ti3+ and Nb4+ and the optimization of electronic structure, which provide more active sites for ion insertion and accelerate electron transport and migration. The optimized sample (TNO-M) demonstrates excellent high-rate capacity and cyclic stability. Specifically, the reversible capacity is 155.4 mAh/g at 10C. A capacity retention ratio of 97.87 % can be maintained after 200 cycles at 1C. Even after 500 cycles at 5C, TNO-M can still deliver a high capacity of 156.4 mAh/g. The strategy of developing high-capacity and high-rate anodes provides a new inspiration for the applications of fast charging of energy-dense LIBs.

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.

Electrospun metal-organic framework materials derived bimetallic oxides as high-efficiency anodes for lithium-ion battery

Energy devices are receiving more and more attention, and this is especially true for lithium-ion batteries. Moreover, applying novel nanostructures in multicomponent systems is a very effective way to promote the development of energy storage systems. This study synthesizes a nitrogen-doped carbon nanofiber encapsulating MOF-derived bimetallic oxide nanomaterial by combining electrospinning and MOF materials. Nitrogen-doped carbon nanofibers are porous and highly conductive, providing structural stability, a practical pathway for lithium ion diffusion, and an essential channel for rapid charge transfer during cycling. The bimetallic oxides derived from the MOF materials provide sufficient space for fast reaction sites and mitigate volume expansion during cycling. When the composite material FNO@NCNFs is used as the anode material for lithium batteries, its reversible capacity is maintained at 1105.4 mAh g−1 after 100 cycles at a current density of 0.1 A g−1. Its capacity reaches 748.5 mAh g−1 after 900 cycles at a current density of 1 A g−1, and at the same time, it exhibits excellent cycling stability, with the coulombic efficiency remaining above 98 %. The material also exhibits a small ion transfer resistance and good rate performance. The structural design approach based on combining MOFs with electrospinning in this study will provide new insights into the design and development of materials for advanced energy storage applications.