High-capacity Anode Materials Research Articles

Interfacial Modulation of a Self-Sacrificial Synthesized SnO2@Sn Core-Shell Heterostructure Anode toward High-Capacity Reversible Li+ Storage.

Sn-based anodes are promising high-capacity anode materials for low-cost lithium ion batteries. Unfortunately, their development is generally restricted by rapid capacity fading resulting from large volume expansion and the corresponding structural failure of the solid electrolyte interphase (SEI) during the lithiation/delithiation process. Herein, heterostructural core-shell SnO2-layer-wrapped Sn nanoparticles embedded in a porous conductive nitrogen-doped carbon (SOWSH@PCNC) are proposed. In this design, the self-sacrificial Zn template from the precursors is used as the pore former, and the LiF-Li3N-rich SEI modulation layer is motivated to average uniform Li+ flux against local excessive lithiation. Meanwhile, both the chemically active nitrogen sites and the heterojunction interfaces within SnO2@Sn are implanted as electronic/ionic promoters to facilitate fast reaction kinetics. Consequently, the as-converted SOWSH@PCNC electrodes demonstrate a significantly boosted Li+ capacity of 961 mA h g-1 at 200 mA g-1 and excellent cycling stability with a low capacity decaying rate of 0.071% after 400 cycles at 500 mA g-1, suggesting their great promise as an anode material in high-performance lithium ion batteries.

Exploring the Storage Mechanism of Alkali Ions in Non-Graphitic Hard Carbon Anodes

This study aims to develop high-capacity hard carbon anode materials for alkali-ion batteries by controlling the microstructures of non-graphitic hard carbon through an annealing protocol and investigating the effects on the alkali-ion storage mechanisms using physical, chemical, and electrochemical analytical techniques. The hard carbon materials were synthesized at temperatures ranging from 900 °C to 1600 °C. Those synthesized at 1100 °C with high surface area and abundant defects exhibited the highest reversible capacity in Li- and K-ion systems, with the storage dominated by surface-adsorption mechanisms. In contrast, the hard carbon compounds prepared at 1400 °C with numerous curve-featured pores delivered the highest reversible capacity in the Na-ion system, indicating that these pores are the preferred Na-ion storage sites, particularly in low-voltage plateau regions. This study provides a comprehensive understanding of the relationship between microstructures and alkali-ion storage mechanisms in non-graphitic hard carbon and highlights the importance of tailoring the microstructures of hard carbon to achieve high specific capacity for the desired alkali-ion species.

Surface Design Engineering of LiTaO3 Coating on Li-Excess Li2NiO2 Cathode Additive for Lithium-Ion Batteries

The latest research has mainly focused on enhancement in the energy density of lithium-ion batteries (LIBs) to satisfy the rigorous industrial demands. As the most common approach for improving the energy density of LIBs, the utilization of high capacity anode materials, such as silicon suboxide (SiOx), has been highlighted, instead of graphite. SiOx anodes are known to have a high specific capacity and low operating voltage (< 0.5 V vs. Li/Li+). However, the severe initial capacity loss induced by the formation of solid electrolyte interphase (SEI) limits their commercial use in LIBs. To compensate for the initial loss of available Li+, the application of Li-excess cathode additives has been considered as the most practical strategy for supplying surplus Li+ during the initial charge process. In this respect, Li2NiO2 is a suitable cathode additive because it offers a high initial charge capacity (≥ 320 mAh g-1) and a compatible operating voltage with commercial cathode materials. Surface protection of Li2NiO2 is still required, however, due to its vulnerability to moisture (H2O) and carbon dioxide (CO2) in the ambient atmosphere. Moreover, Li2NiO2 becomes more structurally unstable during cycle due to oxygen (O2) gas evolution, leading to the formation of microcracks. To overcome these obstacles, we suggest a functional LiTaO3 coating layer onto the surface of Li2NiO2 for structural stabilization. In practice, the LiTaO3 coating layer can effectively suppress the production of impurities (i.e., LiOH and Li2CO3) at the surface of Li2NiO2 after air exposure. Furthermore, the gas evolution and microcracks can be minimized by enhancing the structural stability of Li2NiO2 during cycling. These synergetic effects of the LiTaO3 coating layer can provide clear insights for the development of Li-excess cathode additives for achieving advanced LIBs.

Redox-active anthraquinone-based π-conjugated polymer anode for high-capacity aqueous organic hybrid flow battery

Organic molecules/polymers are currently investigated as redox species for aqueous low-cost hybrid flow batteries. In this work, a redox-active anthraquinone-based conjugated polymer synthesized via a facile electrochemical polymerization approach is reported, which can be employed as a high-capacity anode material for aqueous hybrid flow batteries. The redox-active anthraquinone polymer displays a two-electron-transfer redox reaction at −0.616 V (versus the standard hydrogen electrode, SHE) with fast redox kinetics in aqueous alkaline electrolytes (pH = 12). Paired with a potassium ferrocyanide catholyte, the aqueous hybrid flow battery employed this redox-active anthraquinone polymer as the anode material in aqueous supporting electrolyte of pH = 12 exhibits an open circuit voltage of about 1.09 V, high specific capacity (103.6 mA h g−1 at 2 A g−1) and large mass power density (9.41 W g−1 at 100 % SOC), along with excellent capacity retention (99.948 % per cycle) and energy efficiency (74.1 %) after 100 cycles.

Three-Dimensional Porous Tetrakis Methane and Silane as a High-Capacity Anode Material for Monovalent and Divalent Metal Ion Batteries

Three-Dimensional Porous Tetrakis Methane and Silane as a High-Capacity Anode Material for Monovalent and Divalent Metal Ion Batteries

Advanced inorganic lithium metasilicate binder for high-performance silicon anode

Silicon (Si) is considered a high-capacity anode material with potential for next-generation lithium-ion batteries. However, the commercial application of Si anode is seriously hindered by huge volume variation (>300%) and limited Li+ diffusion ability. Herein, lithium metasilicate (LS), a novel inorganic binder, was innovatively developed to accommodate these challenges. Favorable compatibility is observed between the LS binder and Si nanoparticles (SiNPs) due to the existence of Si element within the LS skeleton. The interaction of the LS binder and SiNPs leads to a strong adhesion effect, enhancing the cycling stability of Si anode. The Si electrode with the LS binder presented an average discharge capacity of 2123 mAh/g at 0.84 A/g after 100 cycles. Furthermore, the presence of the Li+ transport channel within the LS binder enhances Li+ diffusion ability within Si anode. As a result, the average discharge capacity reaches 663 mAh/g at 8.4 A/g. This work thus explored new inorganic binder design approaches for Si anode, contributing to the advancement of high-performance Si anode.

Synthesis and characterization of CuO micro-flowers/PPy nanowires nanocomposites as high-capacity anode material for lithium-ion batteries

Synthesis and characterization of CuO micro-flowers/PPy nanowires nanocomposites as high-capacity anode material for lithium-ion batteries

Design of phosphorus-doped porous hard carbon/Si anode with enhanced Li-ion kinetics for high-energy and high-power Li-ion batteries

With the rapid progress of portable electronics and electric vehicles, high-energy lithium-ion batteries (LIBs) with fast-charging technology are urgently required. Silicon (Si) is considered as the most promising anode candidate for high-energy LIBs but challenging to large-scale commercialization due to its huge volume change and poor conductivity. To develop high-capacity Si-based anode materials with enhanced lithium-ion diffusion and fast reaction kinetics, we design a novel high-Si-content Si/hard carbon composite via scalable methods. The combination between phosphorus-doped hard carbon with porous structure and uniformly distributed Si nanolayers effectively improve lithium-ion kinetics and mitigate the volume change of Si. As a result, the architecture delivers a reversible capacity of 1124 mAh/g at 0.1C and superior cycling stability with an 87.4% capacity retention after 200 cycles at 1C. The 1.5 A h pouch-type full-cell tests further demonstrate good cycling stability and high rate performance at 4C under an electrode density of 1.6 g cm−3 and areal capacity loading of 3.53 mAh cm−2. This work paves a new way for the rational design of Si-based anode materials for high-energy and high-power LIBs.

Facile Constructing Hierarchical Fe3O4@C Nanocomposites as Anode for Superior Lithium-Ion Storage

Ferroferric oxide (Fe3O4) is regarded to be a promising high-capacity anode material for LIBs. However, the capacity attenuates fast and the rate performance is poor due to the dramatic pulverization and sluggish charge transfer properties. To solve these problems, a simple in situ encapsulation and composite method was successfully developed to construct carbon nanotube/nanorod/nanosheet-supported Fe3O4 nanoparticles. Owing to the hierarchical architecture design, the novel structure Fe3O4@C nanocomposites effectively enhance the charge transfer, alleviate pulverization, avoid the agglomeration of Fe3O4 nanoparticles, and also provide superior kinetics toward lithium storage, thereby showing significantly improved reversibility and rate performance. The carbon nanotube/nanorod supported core-shell structure Fe3O4@C nanocomposite displays outstanding high rate capability and stable cycling performance (reversible capability of 1006, 552 and 423 mA h g−1 at 0.2, 0.5 and 1 A g−1 after running 100, 300 and 500 cycles, respectively).

Surface Modification of Micro-Silicon Anode for High-performance Lithium-Ion Batteries

Advanced lithium-ion batteries are urgently needed in consumer electronic products, electric vehicles, and energy storage, while the traditional carbonaceous anode materials with relatively low specific capacity gradually become difficult to meet the practical requirements in the market. Silicon-based anodes are considered one of the most promising alternatives in LIBs with high specific energy due to their considerable theoretical specific capacities. However, the large volume variation and severe surface parasitic reactions still limit the practical application of silicon anode. In this work, to suppress the surface side reactions and great volume changes, the electrochemical inert Li3PO4 is proposed to be coated as the physical barrier between the silicon and electrolyte. The as-coated micro-silicon has been successfully prepared via a facile spray drying method with a low-temperature thermal treatment. Li3PO4 coating layer with high shear modules can not only passivate the surface but also enable to suppression of the severe volumetric expansion and shrinkage of the silicon particle, thus enhancing the initial columbic efficiency and structural integrity of the silicon materials during long-term cycling. The optimized silicon anode with the proper amount of Li3PO4 displays a superior initial columbic efficiency higher than 90% and a highly reversible capacity of 1394 mAh g-1 after charging and discharging 200 times. It is hoped this work should shed light on the modification of high-capacity anode materials.

A novel two-dimensional whorled TiB4 as a high-performance anode material for Li-ion and Na-ion batteries

The search for high storage capacity anode materials has been an important topic in the field of ion batteries. With the gradual development of two-dimensional (2D) materials, their potential as high-performance electrode materials have been demonstrated. Here, using first principles calculations, we investigate the feasibility of novel 2D TiB4 as an ideal anode material for Li/Na ion batteries. Our results indicate that Li/Na ions can be chemically and stably adsorbed on the surface of 2D TiB4. It is noteworthy that the Li capacity of 2D TiB4 is up to 2353.2 mA h g−1 and the Na capacity up to 1764.9 mA h g−1 with a guaranteed low diffusion barrier (0.24 eV for Li; 0.09 eV for Na). Therefore, our calculations show that TiB4 monolayer is an excellent anode material with great potential for ultra-high energy storage devices.

Impact of Functional Groups in Reduced Graphene Oxide Matrices for High Energy Anodes in Lithium-Ion Batteries

Most high capacity anode materials for lithium-ion batteries (LiB) require a carbonaceous matrix. In this context one promising material is reduced graphene oxide (rGO). Herein, we present the influence of different reduction degrees of rGO on its physico-chemical properties, such as crystallinity, specific surface area, electrical conductivity and electrochemical lithiation/delithiation behavior. It is found that a heat treatment under inert and reducing atmospheres increases the long-range order of rGO up to a temperature of 700 °C. At temperatures around 1000 °C, the crystallinity decreases. With decreasing oxygen content, a linear decrease in irreversible capacity during cycle 1 can be observed, along with a significant increase in electrical conductivity. This decrease in irreversible capacity can be observed despite an increase in specific surface area indicating the more significant influence of the oxygen content on the capacity loss. Consequently, the reversible capacity increases continuously up to a carbon content of 84.4 at% due to the thermal reduction. Contrary to expectations, the capacity decreases with further reduction. This can be explained by the loss of functional groups that will be lithiated reversibly, and a simultaneous reduction of long-range order, as concluded from dq/dU analysis in combination with XRD analysis.

Boron-doped porous waste silicon/carbon composite with improved performance for lithium-ion batteries

With the rapid development of the photovoltaic (PV) industry, the amount of PV silicon (Si) produced by cutting is also increased. Therefore, recycling PV Si produced by PV cutting is critical. Herein, we used PV Si to design a kind of boron-doped porous silicon/carbon (B-Si/C) composites through acid etching and freeze-drying methods. The B-Si/C has a uniform size (25–35 nm), rich pores and good dispersibility. Porous Si doped with B can shorten the ion transmission distance. Simultaneously, the outer carbon layer of B-Si/C can relieve the volume expansion of the Si nanoparticles and prevent the Si nanoparticles from agglomerating during charge–discharge cycles. When applied as anodes for lithium-ion batteries (LIBs), the B-Si/C exhibits superior electrochemical performance with a commendable capacity of 1240 mA h g−1 at 420 mA g−1 after 100 cycles. It is very viable environmentally and economically to produce advanced high-capacity anode materials for LIBs using PV Si.

Construction of (BiO)2CO3@ketjen black composite from commercial products by one step mechanical ball milling for long cycle lithium-ion battery anode

At present, it is very important to synthesize new high-capacity anode materials for lithium-ion batteries by simple method. This study describes the successful preparation of (BiO)2CO3@C composites from commercial (BiO)2CO3 and carbon material via a straightforward mechanical ball milling technique. When tested for lithium-ion half-cell, the results showed that (BiO)2CO3@ketjen black composite exhibited obviously enhanced electrochemical performances than the original (BiO)2CO3 and other (BiO)2CO3@C composites. Furthermore, the (BiO)2CO3@ketjen black composite electrode also showed satisfactory long cycle life test, with a charging capacity of 575 mAh g−1 after 750 cycles with a current density of 200 mA g−1 and displaying good capacity retention (96.5% of the initial capacity). These results indicate that (BiO)2CO3@ketjen black composite prepared by one-pot mechanical ball grinding is promising to be used in the next generation of lithium-ion batteries.

Tin-functionalized silicon oxycarbide as a stable, high-capacity anode material for Na-ion batteries

In this study tin-functionalized silicon oxycarbide, Sn/SiOC, composite anode materials are synthesized using a carbon-rich polysiloxane as the preceramic polymer and nano-sized SnO2, which converts to metallic tin via carbothermal reduction at approximately 700 °C. The in-situ Sn formation leads to a uniform distribution of tin particles within a carbon-rich SiOC matrix. Raman spectra show no significant changes despite the carbothermal reduction of SnO2. The composite material provides a stable reversible capacity of 234 mAh g-1. By adjusting the composition and pyrolysis temperature a reversible capacity of 131 mAh g-1 at a high current rate of 2380 mA g-1 is achieved.

Cattail-Grass-Derived Porous Carbon as High-Capacity Anode Material for Li-Ion Batteries.

Cattail-grass-derived porous carbon as high-capacity anode materials were prepared via high-temperature carbonization and activation with KOH. The samples exhibited different structures and morphologies with increasing treatment time. It was found that the cattail grass with activation treatment-1 (CGA-1) sample obtained at 800 °C for 1 h presented excellent electrochemical performance. As an anode material for lithium-ion batteries, CGA-1 showed a high charge-discharge capacity of 814.7 mAh g-1 at the current density of 0.1 A g-1 after 400 cycles, which suggests that it has a great potential for energy storage.

Nonporous Oxide-Terminated Multicomponent Bulk Anode Enabling Energy-Dense Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) are emerging as power sources for large-scale storage owing to their abundant and inexpensive sodium (Na) source, but their limited energy density hinders their commercialization. High-capacity anode materials, such as antimony (Sb), which are potential energy boosters for SIBs, suffer from battery degradation owing to large-volume-changes and structural instability. The rational design of bulk Sb-based anodes to enhance the initial reversibility and electrode density inevitably requires atomic- and microscale-considered internal/external buffering or passivation layers. However, unsuitable buffer engineering causes electrode degradation and lowers energy density. Herein, the rationally designed intermetallic inner and outer oxide buffers for bulk Sb anodes are reported. The two chemistries in the synthesis process provide an atomic-scale aluminum (Al) buffer within the dense microparticles and an external mechanically stabilizing dual oxide layer. The prepared nonporous bulk Sb anode maintained excellent reversible capacity at a high current density and Na-ion full battery evaluations with Na3V2(PO4)3 (NVP) showing negligible capacity decay over 100 cycles. The demonstrated buffer designs for commercially favorable micro-sized Sb and intermetallic AlSb shed light on the stabilization of high-capacity or large-volume-change electrode materials for various metal-ion rechargeable batteries.

Hexagonal Sb Nanocrystals as High-Capacity and Long-Cycle Anode Materials for Sodium-Ion Batteries.

Antimony (Sb) is regarded as a promising anode material for sodium ion batteries (SIBs) on account of its high theoretical specific capacity (∼660 mAh g-1) and low cost. However, the large volume expansion (∼390%) during charging has inhibited its practical application. Herein, hexagonal Sb nanocrystals encapsulated by P/N-co-doped carbon nanofibers (Sb@P-N/C) were prepared using a low-cost but mass-produced electrospinning method. The as-prepared Sb@P-N/C, used as anode material for SIBs, exhibits unexpected cycling stability and rate capability, with 500.1 mAh g-1 at 50 mA g-1 after 200 cycles and 295.6 mAh g-1 at 500 mA g-1 after 400 cycles. Especially, the full battery fabricated by Na (Ni1/3Fe1/3Mn1/3) O2 || Sb@P-N/C possesses a reversible specific capacity of 66.8 mAh g-1 at 50 mA g-1 over 60 cycles. This simple and low-cost fabrication technology combined with unique crystal morphology offers new strategies for the advancement of sodium ion batteries (SIBs) in energy storage and electrical transportation.

A vapor-liquid-solid mechanism for in-situ deposition of ultra-small hollow MoS2 nanoparticles in N-doped carbon foam as an anode of lithium-ion batteries

Although molybdenum disulfide (MoS2) has been nominated as a high theoretical capacity anode material for lithium-ion batteries (LIBs), intrinsic low electrical conductivity and massive volume expansion are significant obstacles to its application investment. Herein, a novel synthesis method has been developed to prepare the carbon foam/MoS2 (CF/MoS2) nanocomposite through an in-situ vapor-liquid-solid (VLS) mechanism to overcome its inherent disadvantages as a LIBs anode. A newfound MoS-polyHIPE, polyHIPE containing Mo and S precursors, was synthesized to provide the reaction confinement spaces. The in-situ reaction between sodium molybdate melt and gaseous sulfur products derived from decomposing the S precursor in the highly nanoporous polymer during low-temperature pyrolysis (700 °C) led to the precipitation of MoS2 nanoparticles in the carbon backbone. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman analysis demonstrated the formation of 1T/2H-MoS2. The TEM and HAADF-STEM micrographs revealed the ultra-small MoS2 nanoparticles with a hollow spherical shape well-distributed in the carbon framework. The unique composite structure of the homogeneously dispersed tiny nanoparticles in a nanoporous matrix caused fast diffusion of lithium ions, separated MoS2 nanoparticles without aggregation, and structural stability. The prepared composite exhibited a high specific capacity of 1051 mAh g−1 after 100 charge/discharge cycles. The composite also exhibited a significant specific capacity of 600 mAh g−1 at the high current density of 3C as an anode material for LIBs.

High-capacity anode materials for lithium-ion batteries: perovskite strontium vanadate with crystalline-amorphous dual-phase structure

Breaking the capacity barrier in intercalation-type anode materials for lithium-ion batteries while preserving other essential electrochemical properties remains a significant challenge. Here, using perovskite SrVO3 as a model, we demonstrate the feasibility of employing defect engineering to provide extra active sites for electrochemical reactions. Defective SrxVO3-δ samples with a unique amorphous-crystalline dual-phase structure are successfully prepared by regulating the nonstoichiometric Sr/V ratio and using a non-equilibrium solution combustion strategy to alleviate nucleation. The dual-phase SrxVO3-δ electrodes, which take advantage of both the high defect concentration advantage of amorphous and the high electrical/ionic conductivity of crystalline, give a high specific capacity of 508 mAh/g at a safe potential of 1.0 V vs. Li/Li+, showing a 40% increase over SrVO3 electrodes and outperforming most state-of-the-art intercalation-based anodes. In addition, when coupling with LiFePO4 cathode, the SrxVO3-δ electrodes can operate over 10,000 cycles with 91% capacity retention, overcoming the limited structural stability exhibited in typical defective electrodes. The study demonstrates the viability of modulating the crystallinity in intercalation-based anodes to enhance electrochemical performance and paves the way for the advancement of Li-ion battery technology.