Performance Anodes For Lithium-ion Batteries Research Articles

Micron silicon-oxide-carbon coated with TiOx(OH)y layer as better performance anode for lithium-ion batteries

Micron-silicon based material is a promising anode material for high performance lithium batteries due to its ultra-high specific capacity. However, the volume expansion exceeds 300 % during charging and discharging, resulting in the collapse of the electrode structure and a rapid decline in electrochemical performance. Coating the surface of silicon-based materials with flexible ionic conductors is an effective method to maintain their high capacity and suppress swelling. Here, to further improve the electrochemical performance of silicon-based materials, we have deposited a titanate-type ionic conductor layer on a micron-sized silicon-carbon oxide (SiOX-C) material to synthesize the SiOX-C@TiOx(OH)y material. The TiOx(OH)y layer not only exhibits the elastic properties of a superpolymer to mitigate swelling strain, but also has a fast capacitance effect to improve its rate performance. In addition, the interfacial charge transport of SiOX-C@TiOx(OH)y is enhanced due to the structural diversity of the TiOx(OH)y layer. For the above mechanisms, the SiOX-C@TiOx(OH)y has a specific capacity of 278.3 mAh g−1 under high current of 3500 mA g−1. Meanwhile, the SiOX-C@TiOx(OH)y with the capacity retention of 67 % is achieved at 2000 mA g−1 after 100 cycles.

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.

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.

Metallic MoS2 grown on CNT as high performance anodes for lithium-ion batteries

To mitigate the structural collapse of MoS2 during charging and discharging, MoS2-CNT composites were fabricated as anodes for lithium-ion batteries (LIBs). Hydroxylation CNT was incorporated to provide growth sites for MoS2 nanosheets, thereby enhancing their overall dispersion. This structure effectively improves the stability during cycling compared to MoS2/CNT, and to some extent improves the structural collapse of MoS2. As a result, the initial discharge capacity of the MoS2-CNT anode was 1194 mAh g−1 and the sustained capacity was 774 mAh g−1 after 200 cycles at 0.5 A g−1.

A novel approach to synthesize micrometer-sized porous Si/SiOx@C with internally and externally interweaved CNTs as a high performance anode for lithium-ion batteries

Silicon-based materials are prospective anodes because of the high capability of lithium (Li) storage, but the large volumetric expansion seriously destroys the integrity of the electrodes and further results in unsatisfactory cycling performance. Reasonable structure design based on low-cost nano silicon (Si) prepared by an feasible method is still an enormous challenge. Herein, the carbon-coated and cross-linked carbon nanotube/porous-Si/SiOx microspheres (CNT/SFDP-Si/SiOx@C) are firstly synthesized by combining an inverse water-in-oil microemulsion approach with magnesiothermic reduction. One high value-added route for utilizing silica fume as the precursor to form nano silicon is provided. The collaborative strategy via wired CNTs network, porous-Si/SiOx flexible matrix, and carbon coating is employed to keep the integrity and stability of electrode structure. Benefiting from the synergistic effect of the flexibility of CNTs network, protection of outer carbon shell, doping of diverse nitrogen (N) species, and accommodation of porous-Si/SiOx, CNT/SFDP-Si/SiOx@C exhibits excellent electrochemical performance. The long cycling lifespan with a reversible capacity of 675.8 mAh g−1 after 1000 cycles at 2 A g−1, a slight decay rate per cycle of 0.018 %, and a high-rate performance are simultaneously obtained. The prelithiated LiFePO4||CNT/SFDP-Si/SiOx@C full cell is also assembled, showing the reversible capacity of 129.4 mAh g−1 at 0.2C.

A Study on the Kinetics and Structural Changes of Silicon during Ball Milling

Enhancing our understanding of the ball milling process is important to optimize silicon amorphization, a key factor in improving the performance of lithium-ion battery anodes. To improve this understanding, we quantitatively studied the kinetics of silicon amorphization during ball milling using x-ray diffraction (XRD) and electrochemical methods, among other methods. The percentage of amorphous and crystalline silicon was deduced by fitting the XRD data and electrochemical results. The resulting trend versus ball milling time was then fitted using the Avrami model. The material resulting from ball milling was further studied using scanning and transmission electron microscopy (SEM/TEM). Under extended milling times, we found that a maximum of 86% of the silicon became amorphous. Similarly, the grain size of the crystalline silicon phase could not be reduced below 6 nm. Our observations suggest that amorphization results from defects creation during ball milling. Amorphization then stops when the grain size reaches a limit where defects are no longer formed. Figure 1

Polymer Tetrabenzimidazole Aluminum Phthalocyanine Complex with Carbon Nanotubes: A Promising Approach for Boosting Lithium-Ion Battery Anode Performance

Polymer Tetrabenzimidazole Aluminum Phthalocyanine Complex with Carbon Nanotubes: A Promising Approach for Boosting Lithium-Ion Battery Anode Performance

Hierarchical Nanoporous N-Doped Carbon for Enhanced Rate Performance of Lithium-Ion Battery Anodes

Hierarchical Nanoporous N-Doped Carbon for Enhanced Rate Performance of Lithium-Ion Battery Anodes

Recycling of waste silicon powder from the photovoltaic industry into high performance porous Si@void@carbon anodes for Li-ion battery

To enhance the performance of lithium-ion battery anodes, this study leverages recycled diamond wire-cut silicon particles, a byproduct of the photovoltaic sector. These particles undergo purification through acid wash and pyrolysis to eliminate contaminants, thereby serving as potential anode materials. The inherent challenge with silicon involves its significant volumetric expansion during lithiation and delithiation, which hampers its viability for commercial applications. Addressing this, the research introduces a facile approach by synthesizing porous silicon (pSi) via the Ag-assisted chemical etching method. Subsequently, a distinctive yolk-shell porous silicon@void@carbon (pSi@V@C) structure is created using a sacrificial template approach, ensuring the formation of voids between the porous silicon core and the carbon shell. This configuration mitigates the detrimental effects of silicon's volume expansion while enhancing electrical conductivity through the carbon shell. The pSi@V@C composite exhibits promising electrochemical performance, demonstrated by an initial discharge capacity of 1826 mAh g-1 and a Coulombic efficiency of 68.6% at 0.1 A g-1. Remarkably, it maintains a capacity of 821.8 mAh g-1 after 550 cycles at 1 A g-1, with a retention rate of 90.4%.

Transient freezing strategy of metastable lithium titanate for high performance lithium-ion battery anodes under high pressure

Lithium-ion batteries (LIBs) with a solid-solution or single-phase intercalation mechanism are considered to be excellent candidates for fast charging and addressing range anxiety, as they have few kinetic energy barriers apart from ion diffusion. In this regard, we capture metastable lithium titanate using High-Pressure High-Temperature (HPHT) synthesis technique under thermodynamic control in only 30 min. Compared with most conventional synthesis methods in the field, the preparation time is only 1.6–3.6% of them. Interestingly, stable and controllable structural defects can be induced under high pressure. Additionally, the HPHT-induced “fracture” structure significantly improves the kinetics of electrolyte storage and exhibits a remarkable pseudocapacitance of up to 89.1%. After 1000 cycles at 10 C, it still retains a reversible capacity of 165 mAh g−1 with a capacity retention rate of 97%. The capture of metastable phase by HPHT technology provides a new perspective and approach for material optimization and design.

Influence of component molar ratios of conjugated polymers on the anode performance in lithium-ion batteries

The change in the ratio of D–A monomers in the polymer skeleton improves the intrinsic electron transport capacity and achieves enhanced electrochemical properties.

Boosting the high-rate performance of lithium-ion battery anodes using MnCo2O4/Co3O4 nanocomposite interfaces.

Herein, a mesoporous MnCo2O4/Co3O4 nanocomposite was fabricated using a polyvinylpyrrolidone (PVP)-assisted hydrothermal synthesis method by maintaining only the non-stoichiometric ratio of Mn and Co (2 : 6), leading to an extra phase of Co3O4 coupled with MnCo2O4. Microstructural analysis showed that the obtained sample has a uniform nanowire-like morphology composed of interconnected nanoparticles. The stoichiometric ratio (2 : 4) was maintained to synthesize pure MnCo2O4 for comparative analysis. However, the obtained structure of pure MnCo2O4 was found to be irregular and fragile. After their employment as anode-active materials, the nanocomposite electrode showed superior high rate capability (1043.8 mA h g-1 at 5C) and long-term cycling stability (773.6 mA h g-1 after 500 cycles at 0.5C) in comparison to the pure MnCo2O4 electrode (771.5 mA h g-1 at 5C and 638.9 mA h g-1 at 0.5C after 500 cycles). It was believed that the extra phase of Co3O4 may also participate in the electrochemical reactions due to its high electrochemically active nature. Benefiting from the appealing architectural features and striking synergistic effect, the integrated MnCo2O4/Co3O4 nanocomposite anode exhibits excellent electrochemical properties and high cycle stability for LIBs.

Forming SnS@C/MoS2 nanotubes with high specific surface area via self-sacrificing template method as superior performance anode for lithium-ion batteries

1) The coated carbon from Sn-MOF carbonization with the nanosheet architecture improves the specific surface area; 2) the heterojunction between SnS and MoS2 provides active sites; 3) the surface carbon provides a large number of active sites.

Effect of rapid thermal annealing on the charge storage kinetics of conductive N-doped SnO2 thin film anodes for Li-ion batteries

This study focuses on the fabrication of a flexible thin film electrode composed of N-doped tin oxide (SnO2: N). The fabrication process involves sputtering SnO2 onto a Cu foil sheet using radio frequency (RF) magnetron sputtering, conducted under an N2 atmosphere. The deposited thin films are subsequently exposed to annealing treatment using rapid thermal annealing (RTA) at temperatures ranging from 200 to 400 °C. The primary objective of this study is to get an understanding of the effects of N-doping, annealing temperature on the growth of SnO2: N. as well as the influence of film thickness on the crystallographic state. We evaluate their thin-film anode performance for lithium-ion batteries (LIBs). The specific capacity of the as-deposited SnO2 thin films standing at 859 mAh g−1 when measured at 1 mA g−1. This enhanced capacity is attributed to the limited crystal growth in ultrathin SnO2, a factor that effectively combats electrode degradation while simultaneously improving the lithium-ion diffusion coefficient and electron kinetics of the electrode. However, the SnO2: N film that undergoes annealing at 400 °C demonstrates remarkable cyclic retention, reaching 82 %. This improvement is due to the enhanced electrical conductivity resulting from annealing, which prevents the aggregation of tin (Sn) and effectively accommodates the volume changes that occur in prolonged cycles. Additionally, this synchronized approach involving sputtering and RTA is proving to be a simple, efficient, and scalable method. It holds the potential to emerge as a valuable strategy to produce anode materials for lithium-ion batteries.

Fe3O4 nanoparticles intercalated reduced graphene oxide nanosheets for supercapacitor and lithium-ion battery anode performance

Fe3O4 nanoparticles intercalated reduced graphene oxide nanosheets for supercapacitor and lithium-ion battery anode performance

Simple ball milling-assisted method enabling N-doped carbon embedded Si for high performance lithium-ion battery anode

Si has been regarded as a hopeful advanced anode of lithium-ion batteries due to its features such as ultrahigh theoretical specific capacity and high natural abundance. But, it suffers from electrochemical irreversibility because of large volumetric change and poor conductivity during cycle. In spite of obtaining enhanced lithium storage performance after compositing with carbon materials, most of the reported Si/C composite anodes lack a simple preparation process. For the new anode materials, the simple preparation process is as important as showing high performance. Herein, an efficient simple method is developed to prepare a composite of N-doped carbon embedding Si nanoparticles (Si@C) to response to the above Si faced challenges. Its preparation process just consists of very simple ball milling and pyrolysis carbonization, showing great simplicity. The findings confirm that the combination of the ball-milling mixing and the use of PVP carbon precursor enables the optimal Si@C-2 composite to have a N-doped carbon embedding structure and a robust interface Si-O-C chemical bond bonding, hence obtaining enhanced conductivity, high electrochemical kinetics and superb structure stability during cycling process. Therefore, the Si@C-2 anode exhibits excellent performance, with 1542 and 794.7 mA h g−1 after 100 and 1000 cycles at 100 and 1000 mA g−1, respectively, superior to many reported Si/C composites. The simple, scalable preparation method and superb performances offer Si@C-2 great promising in advanced LIB anode applications.

Metal cation cross-linked 3D frameworks of Fe3O4 nanospheres encapsulated in graphene nanomesh with enhanced anode performance for lithium-ion batteries

Transition metal oxide (TMO) particles encapsulated in graphene shell has been reported to be an ideal lithium-ion batteries (LIBs) anode due to its well TMO particles volumetric adaptability upon cycling. In this paper, to further enhance the structural stability as well as electrochemical performance of Fe3O4-based electrodes for LIBs, 3D composite structures of Fe3O4 nanospheres (NSs) encapsulated in interconnected holey graphene nanosheets (Ca2+/p-rGO@Fe3O4) were fabricated by facile hydrothermal process using Ca2+ as crosslinker and hydrogen peroxide (H2O2) as etching agent. The composite was characterized by X-ray diffractometer (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM), Fourier Transform Infrared Spectrometer (FTIR), and other test methods. The morphological and structural tests show that Fe3O4 NSs are homogenously embedded in the 3D framework of interconnected graphene nanomesh aerogels. Based on its unique structure, the Ca2+/p-rGO@Fe3O4 composite electrode delivers an initial discharge and charge capacities of 1288 and 783 mA h g−1, respectively, remarkable rate capability at current densities from 0.1 to 2 A g−1 and excellent cyclic stability with respect to that of its counterparts Ca2+/rGO@Fe3O4 electrode, p-rGO@Fe3O4 electrode and rGO@Fe3O4 electrode, which are prepared using a similar synthetic procedure but without the addition of H2O2 or CaCl2 or neither. It is proved that the synergistic effects of Ca2+-induced crosslinking reaction at the edge of GO nanosheets and in-plane pores on graphene coated on the surface of Fe3O4 can enhance the whole electrochemical performance of anode for LIBs.

N-SiOx/graphite/rGO-CNTs@C composite with dense structure for high performance lithium-ion battery anode

SiOx has become one of the most promising anode materials for lithium ion batteries due to its high specific capacity, abundant natural resources and suitable lithium insertion and extraction voltage. However, the low conductivity and the poor cycle performance seriously hinder its practical application. In here, a simple and effective method is proposed to disperse SiOx between carbon materials including flake graphite, reduced graphene oxide (rGO) and carbon nanotubes (CNTs), and then micron-sized N-SiOx/graphite/rGO-CNTs@C (N-SiOx/C@C) composite with dense structure is prepared by coating and pyrolysis of pitch. The synergistic effect of various carbon materials is beneficial to improve the conductivity of the material, and maintain the structural integrity during the cycle. The obtained N-SiOx/C@C anode exhibits high reversible capacity (980.2 mAh·g−1), excellent cycle stability (70 % capacity retention after 500 cycles at 0.5 A·g−1) and excellent rate performance (491.9 mAh·g−1 specific capacity of at 5 A·g−1). The strategy provided here effectively improves the electrochemical performances of SiOx, and the prepared materials show great application potential in the field of lithium ion batteries.

Tailoring the Microstructure of Porous Carbon Spheres as High Rate Performance Anodes for Lithium-Ion Batteries.

Benefiting from their high surface areas, excellent conductivity, and environmental-friendliness, porous carbon nanospheres (PCSs) are of particular attraction for the anodes of lithium-ion batteries (LIBs). However, the regulation of carbon nanospheres with controlled pore distribution and graphitization for delivering high Li+ storage behavior is still under investigation. Here, we provide a facile approach to obtain PCSs with different microstructures via modulating the carbonization temperatures. With the processing temperature of 850 °C, the optimized PCSs exhibit an increased surface area, electrical conductivity, and enhanced specific capacity (202 mA h g-1 at 2 A g-1) compared to the PCSs carbonized at lower temperatures. Additionally, PCSs 850 provide excellent cyclability with a capacity retention of 83% for 500 cycles. Such work can pave a new pathway to achieve carbon nanospheres with excellent performances in LIBs.

Electron-rich hybrid matrix to enhance molybdenum oxide-based anode performance for Lithium-Ion batteries

Although MoO2-based electrodes have been intensively studied as potential candidate anodes for lithium-ion batteries (LIBs) based on their high theoretical capacity (840 mAh g−1 and 5447 mAh cm−3), common issues such as severe volume variation, electrical conductivity loss, and low ionic conductivity, are prevalent. In this study, we demonstrate enhanced Li-ion kinetics and electrical conductivity of MoO2-based anodes with ternary MoO2-Cu-C composite materials. The MoO2-Cu-C was synthesized via two-step high energy ball milling where Mo and CuO are milled, followed by the secondary milling with C. With the introduction of the Cu-C hybrid matrix in MoO2 nanoparticles via the element transfer method using mechanochemical reactions, the sluggish Li-ion diffusion and unstable cycling behavior were significantly improved. The inactive Cu-C matrix contributes to the increase in electrical and ionic conductivity and mechanical stability of active MoO2 during cycling, as characterized by various electrochemical analyses and ex situ analysis techniques. Hence, the MoO2-Cu-C anode delivered promising cycling performance (674 mAh g−1 (at 0.1 A g−1) and 520 mAh g−1 (at 0.5 A g−1), respectively, after 100 cycles) and high-rate property (73% retention at 5 A g−1 as comparison with the specific capacity at 0.1 A g−1). The MoO2-Cu-C electrode is a propitious next-generation anode for LIBs.