Anode Material For Na-ion Batteries Research Articles

Stanene nanomeshes as anode materials for Na-ion batteries

A two-dimensional stanene nanomesh is proposed as a promising anode material for Na-ion batteries.

SnP nanocrystals as anode materials for Na-ion batteries

Sodium ion batteries based on SnP NCs and sodium(i) bis(fluorosulfonyl)imide electrolyte displayed high reversible capacities and cycling stability.

Ultrahigh rate sodium ion storage with nitrogen-doped expanded graphite oxide in ether-based electrolyte

Nitrogen-doped graphite oxide can serve as anode material for Na-ion battery with high initial coulombic efficiency and excellent rate properties.

Nanoflower-like N-doped C/CoS2 as high-performance anode materials for Na-ion batteries.

Novel nanoflower-like N-doped C/CoS2 spheres assembled from 2D wrinkled CoS2 nanosheets were synthesized through a facile one-pot solvothermal method followed by sulfurization. Ascribed to the optimized 3D nanostructure and rational surface engineering, the unique hierarchical structure of the nanoflower-like C/CoS2 composites showed an excellent sodium ion storage capacity accompanied by high specific capacity, superior rate performance and long-term cycling stability. Specifically, the conductive interconnected wrinkled nanosheets create a number of mesoporous structures and thus can greatly release the mechanical stress caused by Na+ insertion/extraction. Besides, it was observed from the experiments that many extra defect vacancies and Na+ storage sites are introduced by the nitrogen doping process. It was also observed that the crosslinked 2D nanosheets can effectively reduce the diffusion lengths of sodium ions and electrons, resulting in an outstanding rate performance (>700 mA h g-1 at 1 A g-1 and 458 mA h g-1 at even 10 A g-1) and extraordinary cycling stability (698 mA h g-1 at 1 A g-1 after 500 cycles). The results provide a facile approach to fabricate promising anode materials for high-performance sodium-ion batteries (SIBs).

Theoretical investigation of zirconium carbide MXenes as prospective high capacity anode materials for Na-ion batteries

Large charge transfer and small lattice mismatch are beneficial for second layer Na atom adsorption.

Biphase-Interface Enhanced Sodium Storage and Accelerated Charge Transfer: Flower-Like Anatase/Bronze TiO2/C as an Advanced Anode Material for Na-Ion Batteries.

Flower-like assembly of ultrathin nanosheets composed of anatase and bronze TiO2 embedded in carbon is successfully synthesized by a simple solvothermal reaction, followed with a high-temperature annealing. As an anode material in sodium-ion batteries, this composite exhibits outstanding electrochemical performances. It delivers a reversible capacity of 120 mA h g-1 over 6000 cycles at 10 C. Even at 100 C, there is still a capacity of 104 mA h g-1. Besides carbon matrix and hierarchical structure, abundant interfaces between anatase and bronze greatly enhance the performance by offering additional sites for reversible Na+ storage and improving the charge-transfer kinetics. The interface enhancements are confirmed by discharge/charge profiles, rate performances, electrochemical impedance spectra, and first-principle calculations. These results offer a new pathway to upgrade the performances of anode materials in sodium-ion batteries.

Structure-dependent performance of TiO2/C as anode material for Na-ion batteries

The performance of energy storage materials is highly dependent on their nanostructures. Herein, hierarchical rod-in-tube TiO2 with a uniform carbon coating is synthesized as the anode material for sodium-ion batteries by a facile solvothermal method. This unique structure consists of a tunable nanorod core, interstitial hollow spaces, and a functional nanotube shell assembled from two-dimensional nanosheets. By adjusting the types of solvents used and reaction time, the morphologies of TiO2/C composites can be tuned to nanoparticles, microrods, rod-in-tube structures, or microtubes. Among these materials, rod-in-tube TiO2 with a uniform carbon coating shows the highest electronic conductivity, specific surface area (336.4m2g−1), and porosity, and these factors lead to the best sodium storage capability. Benefiting from the unique structural features and improved electronic/ionic conductivity, the as-obtained rod-in-tube TiO2/C in coin cell tests exhibits a high discharge capacity of 277.5 and 153.9 mAh g−1 at 50 and 5000mAg−1, respectively, and almost 100% capacity retention over 14,000 cycles at 5000mAg−1. In operando high-energy X-ray diffraction further confirms the stable crystal structure of the rod-in-tube TiO2/C during Na+ insertion/extraction. This work highlights that nanostructure design is an effective strategy to achieve advanced energy storage materials.

Enhancing the Sequential Conversion-Alloying Reaction of Mixed Sn-S Hybrid Anode for Efficient Sodium Storage by a Carbon Healed Graphene Oxide.

To date, the possible depletion of lithium resources has become relevant, giving rise to the interest in Na-ion batteries (NIBs) as promising alternatives to Li-ion batteries. While extensive investigations have examined various transition metal oxides and chalcogenides as anode materials for NIBs, few of these have been able to utilize their high specific capacity in sodium-based systems because of their irreversibility in a charge/discharge process. Here, the mixed Sn-S nanocomposites uniformly distributed on reduced graphene oxide are prepared via a facile hydrothermal synthesis and a unique carbothermal reduction process, producing ultrafine nanoparticle with the size of 2 nm. These nanocomposites are experimentally confirmed to overcome the intrinsic drawbacks of tin sulfides such as large volume change and sluggish diffusion kinetics, demonstrating an outstanding electrochemical performance: an excellent specific capacity of 1230 mAh g-1 , and an impressive rate capability (445 mAh g-1 at 5000 mA g-1 ). The electrochemical behavior of a sequential conversion-alloying reaction for the anode materials is investigated, revealing both the structural transition and the chemical state in the discharge/charge process. Comprehension of the reaction mechanism for the mixed Sn-S/rGO hybrid nanocomposites makes it a promising electrode material and provides a new approach for the Na-ion battery anodes.

Sn-MOF derived bimodal-distributed SnO2 nanosphere as a high performance anode of sodium ion batteries with high gravimetric and volumetric capacities

This paper reported a high tap density SnO2 nanosphere with bimodal sizes distribution, which derived from Sn-based metal-organic frameworks (Sn-MOF) precursors. When used as anodes for Na-ion batteries, the SnO2 nanosphere was demonstrated with a high reversible sodium storage capacity of 417mAhg−1 at a current density of 50mAg−1 after 100 cycles. Even at a high current density of 1200mAg−1, a reversible capacity of 105mAhg−1 can be obtained. Additionally, regarding to the packed volumetric capacity, the SnO2 nanosphere electrode demonstrated a high value of around 970mAhcm−3, can be considered as a high volumetric capacity anode material. The excellent electrochemical performance could be ascribed to aspects of structural stability, high packing density and high Na+ diffusion rates of the SnO2 nanosphere electrode. This work provides a new pathway to prepared nanostructured SnO2 materials, and demonstrated a high performance anode material for Na-ion battery with great specific capacity and cycling performance.

Elucidating the reaction mechanism of SnF2@C nanocomposite as a high-capacity anode material for Na-ion batteries

Sn-based materials have drawn great attention as anodes for rechargeable batteries because of their extremely high theoretical energy storage capacities. Herein, a nanocomposite based on SnF2 and acetylene black is proposed as a high-performance anode material for sodium-ion batteries and their electrochemical performances, as well as related energy storage mechanism, are investigated. The nanocomposite electrode delivered a high reversible capacity of 563mAhg−1 which is considerably improved compared to a reversible capacity of 323mAhg−1 of the micron-sized bare SnF2 electrode. The nanocomposite electrode shows superior rate capability and delivers a reversible capacity of 191mAhg−1 at a high current density of 1C, while the bare electrode delivers negligible capacities. The changes in crystallographic structure are observed using in-situ XRD and the results reveal the existence of a solid solution of two or more species during dis/charging. The electronic and atomic configurations depending on the state of dis/charging are systematically investigated using ex-situ X-ray absorption spectroscopy. The results reveal that the valence change of Sn follows the conversion (SnF2 + 2Na → Sn + 2NaF) and alloying (Sn + XNa → SnNaX) reaction upon sodium insertion into a composite.

Utilizing the full capacity of carbon black as anode for Na-ion batteries via solvent co-intercalation

Carbonaceous materials have long been considered promising anode materials for Na-ion batteries. However, the electrochemical performance of conventional carbon anodes is generally poor because the sodium ion storage solely relies on the disordered region of the carbon materials in a carbonate-based electrolyte. The solvent co-intercalation mechanism for Na ions has been recently reported in natural graphite anodes for Na-ion batteries with ether-based electrolytes, but their capacities are still unsatisfactory. We show here for the first time that by combining regular Na ion storage in the disordered carbon layer and solvent co-intercalation mechanism in the graphitized layer of a commercial N330 carbon black as an anode material for Na-ion batteries in ether-based electrolyte, the reversible capacity could be fully realized and doubled in magnitude. This unique sodium intercalation process resulted in a significantly improved electrochemical performance for the N330 electrode with an initial reversible capacity of 234 mAh·g–1 at 50 mA·g–1 and a superior rate capability of 105 mAh·g–1 at 3,200 mA·g–1. When cycled at 3,200 mA·g–1 over 2,000 cycles, the electrode still exhibited a highly reversible capacity of 72 mAh·g–1 with a negligible capacity loss per cycle (0.0167%). Additionally, surface-sensitive C K-edge X-ray absorption spectroscopy, with the assistance of electrochemical and physicochemical characterizations, helped in identifying the controlled formation and evolution of a thin and robust solid electrolyte interphase film. This film not only reduced the resistance for sodium ion diffusion, but also maintained the structural stability of the electrode for extended cycle reversibility. The superior electrochemical performance of N330 carbon black strongly demonstrated the potential of applying ether-based electrolytes for a wide range of carbon anodes apart from natural graphite.

Conversion Reaction of Copper Sulfide Based Nanohybrids for Sodium-Ion Batteries

Intercalation-based anode materials for Na-ion batteries show relatively unfavorable electrochemical performances compared with those of Li-ion batteries because of the larger and heavier Na ion, as well as its higher electrode potential. In contrast, conversion-reaction-based anode materials have great potential for use in Na-ion batteries. In this study, copper sulfide nanodisks (CuS-NDs) were fabricated by a simple low-temperature reaction and applied as the anode materials for Na-ion batteries with acid-treated single-walled carbon nanotubes (a-SWCNTs), which act as a paperlike nanohybrid. The nanohybrids had a high reversible capacity of ca. 610 mA h g–1 and high rate capabilities at current rates from 0.1 to 3 A g–1 during the conversion reaction that reversibly forms Na2S and Cu metal. In addition, their electrochemical performances were stable and were maintained over 500 repetitive cycles; this stability arises from the unique nanohybrid structure, in which CuS-NDs are bound together by the a-SWC...

One step synthesis of SnS2 nanosheets assembled hierarchical tubular structures using metal chelate nanowires as a soluble template for improved Na-ion storage

SnS2 material is considered asa promising anode material for Na-ion batteries (NIBs) because of its unique layered structure and high theoretical capacity. However, SnS2 nanosheets are easily overlapped during synthesis and cycling process. Also, they have to experience large volume change during repeated sodiation-desodiation processes. A promising concept is the application of hierarchical hollow structures for improving electrode stability upon cycling. However, they usually rely on template methods that require complex procedures such as chemical etching or calcination to remove inner template. Here, we demonstrate a simple and innovative strategy for fabricating the SnS2 nanosheets assembled hierarchical tubular structures (SnS2 NS⊂HTSs) by using cobalt-nitrilotriacetic acid chelate nanowires as soluble template, which makes shell growth and core template dissolution occur simultaneously in one step reaction. Owing to the hollow interior and well separated nanosheets with maximally exposed edges, the SnS2 NS⊂HTSs exhibit excellent electrochemical performance. When evaluated as the anode material for NIBs, it delivers a high discharge capacity of 708mAhg−1 at 50mAg−1 and still remains up to 414mAhg−1 after 50 cycles.

Ab initio study of sodium cointercalation with diglyme molecule into graphite

The cointercalation of sodium with the solvent organic molecule diglyme into graphite, forming a ternary graphite intercalation compound (t-GIC), can resolve the difficulty of making the stage 1 Na-GIC in order to use as a potential anode for Na-ion batteries (NIBs). To clarify the mechanism of such cointercalation, we investigate the atomistic structure, energetics, electrochemical properties, ion and electron conductance, and charge transferring upon the de/intercalation of the solvated Na-diglyme ion into graphite with ab initio calculations. It is found that the t-GICs Na(digl)2Cn have the lowest negative intercalation energy at n≈21, the Na(digl)2 complex diffuses relatively fast in the interlayer space, and the electronic conductance can be enhanced upon the cointercalation compared with graphite. The calculations reveal that the diglyme molecule as well as Na atom donates electrons to the graphene layer, indicating an ionic bond between the graphene layer and the diglyme molecule. We belive that this work will contribute to the development of graphite-based anode materials for NIBs.

Fast microwave synthesis of SnO2@graphene/N-doped carbons as anode materials in sodium ion batteries

Hybrid SnO2@graphene (SG) and SnO2@graphene/N-doped carbon (SGN) structures are synthesized by a fast microwave method and tested as anode materials for Na-ion batteries. In these structures, graphene not only acts as a conducting material but also as supporting material to prevent the volume expansion of the SnO2 nanoparticles. Additional N-doped carbon coating leads to improved electrochemical performances providing better electronic conductivity resulting over 423 mAh/g capacity after 180 cycles at C/5 with SGN, while SG only provides 170 mAh/g capacities.

Synthesis of Mesoporous Co2+-Doped TiO2 Nanodisks Derived from Metal Organic Frameworks with Improved Sodium Storage Performance.

TiO2 is a most promising anode candidate for rechargeable Na-ion batteries (NIBs) because of its appropriate working voltage, low cost, and superior structural stability during chage/discharge process. Nevertheless, it suffers from intrinsically low electrical conductivity. Herein, we report an in situ synthesis of Co2+-doped TiO2 through the thermal treatment of metal organic frameworks precursors of MIL-125(Ti)-Co as a superior anode material for NIBs. The Co2+-doped TiO2 possesses uniform nanodisk morphology, a large surface area and mesoporous structure with narrow pore distribution. The reversible capacity, Coulombic efficiency (CE) and rate capability can be improved by Co2+ doping in mesoporous TiO2 anode. Co2+-doped mesoporous TiO2 nanodisks exhibited a high reversible capacity of 232 mAhg-1 at 0.1 Ag1-, good rate capability and cycling stability with a stable capacity of about 140 mAhg-1 at 0.5 Ag1- after 500 cycles. The enhanced Na-ion storage performance could be due to the increased electrical conductivity revealed by Kelvin probe force microscopy measurements.

Synthesis, Electrochemical Properties of Sns/Rgo Nanocomposite As a Negative Electrode Material for Na-Ion Batteries

To date, there has been much research on electrochemical study of lithium ion batteries. However, the question has also been raised for depletion of lithium resources, causing interest in Na-ion batteries (NIBs). While extensive investigations on various transition metal oxides and chalcogenides as an anode material for NIBs have been carried out, few of them have been able to utilize their high specific capacity in sodium-based systems. Here, the mixed Sn-S nanocomposites on reduced graphene oxide are prepared via a facile hydrothermal synthesis and a unique carbo-thermal reduction process, producing ultrafine nanoparticle with a size of under 2 nm. It has been confirmed to overcome the intrinsic properties of tin sulfides such as large volume change and sluggish diffusion kinetics by experimental results, which demonstrating an outstanding electrochemical performance; excellent specific capacity of 1230 mAh g-1, impressive rate capability (445 mAh g-1 at 5000 mA g-1) and cycling stability. The electrochemical behaviors of conversion-alloying reactions for the anode materials are also investigated revealing both the structural transition and the chemical state in the discharge/charge process. Comprehension of the reaction mechanism for the mixed Sn-S/rGO hybrid nanocomposites makes it a promising electrode material and provide a new perspective on the anode field for Na ion batteries.

Interactions of Nanostructured TiO2 with Nonaqueous Electrolytes for Na-Ion Batteries

Current shifts towards renewable energy technologies have increased the drive for high performance and cost effective battery systems. Sodium ion batteries present a promising alternative to the commonly used lithium-ion batteries and offer several benefits such as low cost and high availability. While lithium-ion battery systems have been studied intensively, it has become apparent that the interfacial chemistry differs significantly for sodium ion batteries, even when using the same solvents. In previous work, we have shown that amorphous TiO2 nanotube electrodes are a suitable anode materials for Na-ion batteries. The optimization of electrolytes is important to develop a system with good solubility, high transport properties, electrochemical and interfacial stability. In this work, we have investigated the electrochemical properties of TiO2 nanotube electrodes - as a model system - in various electrolytes containing different solvent mixtures (cyclic and acyclic carbonates) with NaClO4 and NaPF6 salt. In addition, we have conducted fundamental studies of chemical, thermal, and electrochemical stability of the chosen sodium-based electrolytes with a phosphazene-based additive FM2 as well as the commonly used FEC additive.

Antimony Anchored with Nitrogen-Doping Porous Carbon as a High-Performance Anode Material for Na-Ion Batteries.

Antimony represents a class of unique functional materials in sodium-ion batteries with high theoretical capacity (660 mA h g-1). The utilization of carbonaceous materials as a buffer layer has been considered an effective approach to alleviate rapid capacity fading. Herein, the antimony/nitrogen-doping porous carbon (Sb/NPC) composite with polyaniline nanosheets as a carbon source has been successfully achieved. In addition, our strategy involves three processes, a tunable organic polyreaction, a thermal annealing process, and a cost-effective reduction reaction. The as-prepared Sb/NPC electrode demonstrates a great reversible capacity of 529.6 mA h g-1 and an outstanding cycling stability with 97.2% capacity retention after 100 cycles at 100 mA g-1. Even at 1600 mA g-1, a superior rate capacity of 357 mA h g-1 can be retained. Those remarkable electrochemical performances can be ascribed to the introduction of a hierarchical porous NPC material to which tiny Sb nanoparticles of about 30 nm were well-wrapped to buffer volume expansion and improve conductivity.

Cobalt phosphide nanoparticles embedded in nitrogen-doped carbon nanosheets: Promising anode material with high rate capability and long cycle life for sodium-ion batteries

Cobalt phosphide (CoP) nanoparticles which were uniformly embedded in N-doped C nanosheets (CNSs) were fabricated via the simple one-step calcination of a Co-based metal–organic framework (MOF) and red P and exhibited a high capacity, fast kinetics, and a long cycle life. This CoP/CNS composite contained small CoP particles (approximately 11.3 nm) and P–C bonds. When its electrochemical properties were evaluated by testing CoP/Na coin cells, the composite delivered a Na-storage capacity of 598 mAh·g−1 at 0.1 A·g−1 according to the total mass of the composite, which means that the capacity of pure CoP reached 831 mAh·g−1. The composite also exhibited a high rate capability and long-term cyclability (174 mAh·g−1 at 20 A·g−1 and 98.5% capacity retention after 900 cycles at 1 A·g−1), which are commonly attributed to robust P–C bonding and highly conductive CNSs. When the reaction mechanism of the CoP/CNS composite was investigated, a conversion reaction expressed as CoP + 3Na+ + 3e− ↔ Co + Na3P was observed. The outstanding Na-storage properties of the CoP/CNS composite may suggest a new strategy for developing high-performance anode materials for Na-ion batteries.