Sodium-ion Storage Properties Research Articles

Ball‐Milling Synthesis of Richly Oxygenated Graphene‐Like Nanoplatelets from used Lithium Ion Batteries and Its Application for High Performance Sodium Ion Battery Anode

AbstractThe exploration of waste graphite from used lithium ion batteries (LIBs) and its derivatives for versatile applications is an efficient route to promote the environmental and eco‐friendly recycling of used LIBs. Sodium ion batteries (SIBs) are alternative candidates to LIBs mainly due to similar electrochemical mechanism of SIBs to LIBs and rich natural resource of Na. Herein, a holey waste graphite (hGw) with well‐defined porous structure is produced by the annealing of lithiated waste graphite (Li/Gw) from used LIBs under a flow gas of H2O and subsequent lithium leaching in DI water. Benefiting from the holey structure of hGw, holey graphene nanoplatelets (hGnw) with ultrahigh‐level edge‐grafted oxygen groups (≈37.8 at%) are synthesized by mechanical balling of hGw. As anode for SIBs, the hGnw present outstanding sodium ion storage properties with high initial Coulombic efficiency of 82.4%, high reversible capacity (e.g., 416.1 mAh g−1 at 0.03 A g−1), excellent rate capability (e.g., 153.3 mAh g−1 at 2 A g−1), and long‐term cycling stability (e.g., 152.7 mAh g−1 after 400 cycles at 1.5 A g−1).

Amorphous Modulation of Atomic Nb-O/N Clusters with Asymmetric Coordination in Carbon Shells for Advanced Sodium-Ion Hybrid Capacitors.

Anode materials with excellent properties have become the key to develop sodium-ion hybrid capacitors (SIHCs) that combine the advantages of both batteries and capacitors. Amorphous modulation is an effective strategy to realize high energy/power density in SIHCs. Herein, atomically amorphous Nb-O/N clusters with asymmetric coordination are in situ created in N-doped hollow carbon shells (Nb-O/N@C). The amorphous clusters with asymmetric Nb-O3/N1 configurations have abundant charge density and low diffusion energy barriers, which effectively modulate the charge transport paths and improve the reaction kinetics. The clusters are also enriched with unsaturated vacancy defects and isotropic ion-transport channels, and their atomic disordering exhibits high structural stress buffering, which are strong impetuses for realizing bulk-phase-indifferent ion storage and enhancing the storage properties of the composite. Based on these features, Nb-O/N@C achieves notably improved sodium-ion storage properties (reversible capacity of 240.1 mAh g-1 at 10.0 A g-1 after 8000 cycles), and has great potential for SIHCs (230Wh Kg-1 at 4001.5W Kg-1). This study sheds new light on developing high-performance electrodes for sodium-ion batteries and SIHCs by designing amorphous clusters and asymmetric coordination.

Hierarchical porous Na3V2(PO4)3/graphene microspheres with enhanced sodium-ion storage properties

Hierarchical porous Na3V2(PO4)3/graphene microspheres with enhanced sodium-ion storage properties

Honeycomb-Structured MoSe2 /rGO Composites as High-Performance Anode Materials for Sodium-Ion Batteries.

Sodium-ion batteries are a promising substitute for lithium batteries due to the abundant resources and low cost of sodium. Herein, honeycomb-shaped MoSe2 /reduced graphene oxide (rGO) composite materials are synthesized from graphene oxide (GO) and MoSe2 through a one-step solvothermal process. Experiments show that the 3D honeycomb structure provides excellent electrolyte penetration while alleviating the volume change during electrochemical cycling. An anode prepared with MoSe2 /rGO composites exhibits significantly improved sodium-ion storage properties, where a large reversible capacity of 215mAhg-1 is obtained after 2700 cycles at the current density of 30.0Ag-1 or after 5900 cycles at 8.0Ag-1 . When such an anode is paired with Na3 V2 (PO4 )3 to form a full cell, a reversible specific capacity of 107.5mAhg-1 can be retained after 1000 cycles at the current of 1.0Ag-1 . Transmission electron microscopy, X-ray photoelectron spectroscopy and in situ X-ray diffraction (XRD) characterization reveal the reversible storage reaction of Na ions in the MoSe2 /rGO composites. The significantly enhanced sodium storage capacity is attributed to the unique honeycomb microstructure and the use of ether-based electrolytes. This study illustrates that combining rGO with ether-based electrolytes has tremendous potential in constructing high-performance sodium-ion batteries.

Synthesis of Iron Sulfide Nanocrystals Encapsulated in Highly Porous Carbon-Coated CNT Microsphere as Anode Materials for Sodium-Ion Batteries.

Highly porous carbon materials with a rationally designed pore structure can be utilized as reservoirs for metal or nonmetal components. The use of small-sized metal or metal compound nanoparticles, completely encapsulated by carbon materials, has attracted significant attention as an effective approach to enhancing sodium ion storage properties. These materials have the ability to mitigate structural collapse caused by volume expansion during the charging process, enable short ion transport length, and prevent polysulfide elution. In this study, a concept of highly porous carbon-coated carbon nanotube (CNT) porous microspheres, which serve as excellent reservoir materials is suggested and a porous microsphere is developed by encapsulating iron sulfide nanocrystals within the highly porous carbon-coated CNTs using a sulfidation process. Furthermore, various sulfidation processes to determine the optimal method for achieving complete encapsulation are investigated by comparing the morphologies of diverse iron sulfide-carbon composites. The fully encapsulated structure, combined with the porous carbon, provides ample space to accommodate the significant volume changes during cycling. As a result, the porous iron sulfide-carbon-CNT composite microspheres exhibited outstanding cycling stability (293mA h g-1 over 600 cycles at 1 A g-1 ) and remarkable rate capability (100mA h g-1 at 5 A g-1 ).

Epitaxial growth of Cu2-xSe on Cu (220) crystal plane as high property anode for sodium storage

Three-dimentional (3D) transition metal selenides with sufficient channels could produce significant superiority on enhancing reaction kinetics for sodium-ion batteries. However, the thorough exploration of 3D architecture with a facile strategy is still challenging. Here we report that a polycrystalline Cu2-xSe film was epitaxial grown on (220) facets-exposed Cu by direct selenization of a nanoporous Cu skeleton, which is obtained by dealloying rolled CuMn@Cu alloy foil. Density functional theory calculation result shows strong adsorption energy for Se atoms on Cu (220) planes during selenization reaction, rendering a low energy consumption. By virtue of this core-shell 3D nanoporous architecture to offer abundant active sites and endow fast electron/ion transportation, the nanoporous Cu2-xSe@Cu-0.15 composite electrode exhibits remarkable sodium-ion storage properties with high reversible capacity of 950.6 μAh/cm2 at 50 μA/cm2, suprior rate capability of 457.6 μAh/cm2 at 500 μA/cm2, as well as an ultra-long stability at a high current density. Mechanism investigation reveals that the electrochemical reaction is a typical conversion-type reaction with different intermediates. This novel electrode synthetic strategy provides useful instructions to design the high-performance anode material for sodium-ion batteries.

Construction of Small FeS2 Nanoparticles Embedded in Porous Nitrogen-Doped Carbon with Enhanced Sodium Ion Storage Properties

Construction of Small FeS2 Nanoparticles Embedded in Porous Nitrogen-Doped Carbon with Enhanced Sodium Ion Storage Properties

Water-Soluble Binders That Improve Electrochemical Sodium-Ion Storage Properties in a NaTi2(PO4)3 Anode

Water-soluble binders are demonstrated to provide significantly better capacity, cycle life stability and rate response for NASICON-type NaTi2(PO4)3 Na-ion battery anodes during reversible sodiation compared to electrodes made using polyvinylidene difluoride-containing slurries. The role of carboxymethyl cellulose (CMC) binders on the physical structure and chemical interfacial reactions with sodium-poor NaTi2(PO4)3 are uncovered using electron microscopy and spectroscopy data and we show that a more stable NASICON NaTi2(PO4)3 structure is found from the desodiation process from compensation of sodium deficiencies in the NaTi2(PO4)3 by extra sodium from the CMC binder. When the binder comprises CMC and a styrene butadiene rubber (SBR) additive, the electrode delivers significantly better voltammetric and galvanostatic electrochemical response with a specific capacity of ∼120 mAh g−1 with capacity retention of 90.5% for 500 cycles at 0.2 C (1 C = 133 mAh g−1), and ∼54 mAh g−1 at 20 C. The durability of the electrode during cycling and the stability of the redox processes ensures a higher capacity, longer cycle life electrode which is important for sustainable materials development for Na-ion technologies.

Boosting the sodium-ion storage capability of MoSe2 through the synergistic effect of rational sulfur substituting and carbon compositing

Molybdenum selenide (MoSe2) has been regarded as a promising anode for sodium-ion storage due to its large interlayer space, acceptable electronic conductivity, and considerable theoretical capacity, but suffers insufficient active sites and serious volume variation, leading to low reversible capacity and poor cycling lifespans. Herein, a facile one-pot hydrothermal method is developed to achieve sulfur substituting and carbon compositing simultaneously and employed to boost the sodium ion storage properties of MoSe2. The effects of sulfur substituting and carbon compositing on the redox kinetics and sodium-ion storage performance are investigated. In short, sulfur substitution mainly enhances the electronic/ionic conductivity and specific capacity of the MoSe2 by tailoring the electron structures and creating anionic vacancies. Carbon compositing mainly improves the cycling stability due to the alleviative aggregation of active materials and the prohibited active materials dissolution. As a result, the optimized MoSe2-xSx@C electrode presents 348.6 mAh g−1 at 0.1 A g−1, and can endure long-term cycling at 4 A g−1 after 600 cycles with acceptable capacity retention of 83.9%, much better than the pure MoSe2 electrode and the MoSe2-xSx electrodes. This work may provide a facile method to enhance the sodium ion storage properties of transition metal dichalcogenides.

Surface-redox sodium-ion storage in anatase titanium oxide

Sodium-ion storage technologies are promising candidates for large-scale grid systems due to the abundance and low cost of sodium. However, compared to well-understood lithium-ion storage mechanisms, sodium-ion storage remains relatively unexplored. Herein, we systematically determine the sodium-ion storage properties of anatase titanium dioxide (TiO2(A)). During the initial sodiation process, a thin surface layer (~3 to 5 nm) of crystalline TiO2(A) becomes amorphous but still undergoes Ti4+/Ti3+ redox reactions. A model explaining the role of the amorphous layer and the dependence of the specific capacity on the size of TiO2(A) nanoparticles is proposed. Amorphous nanoparticles of ~10 nm seem to be optimum in terms of achieving high specific capacity, on the order of 200 mAh g−1, at high charge/discharge rates. Kinetic studies of TiO2(A) nanoparticles indicate that sodium-ion storage is due to a surface-redox mechanism that is not dependent on nanoparticle size in contrast to the lithiation of TiO2(A) which is a diffusion-limited intercalation process. The surface-redox properties of TiO2(A) result in excellent rate capability, cycling stability and low overpotentials. Moreover, tailoring the surface-redox mechanism enables thick electrodes of TiO2(A) to retain high rate properties, and represents a promising direction for high-power sodium-ion storage.

Self-supporting network-structured MoS2/heteroatom-doped graphene as superior anode materials for sodium storage.

Layered graphene and molybdenum disulfide have outstanding sodium ion storage properties that make them suitable for sodium-ion batteries (SIBs). However, the easy and large-scale preparation of graphene and molybdenum disulfide composites with structural stability and excellent performance face enormous challenges. In this study, a self-supporting network-structured MoS2/heteroatom-doped graphene (MoS2/NSGs-G) composite is prepared by a simple and exercisable electrochemical exfoliation followed by a hydrothermal route. In the composite, layered MoS2 nanosheets and heteroatom-doped graphene nanosheets are intertwined with each other into self-supporting network architecture, which could hold back the aggregation of MoS2 and graphene effectively. Moreover, the composite possesses enlarged interlayer spacing of graphene and MoS2, which could contribute to an increase in the reaction sites and ion transport of the composite. Owing to these advantageous structural characteristics and the heteroatomic co-doping of nitrogen and sulfur, MoS2/NSGs-G demonstrates greatly reversible sodium storage capacity. The measurements revealed that the reversible cycle capacity was 443.9 mA h g-1 after 250 cycles at 0.5 A g-1, and the rate capacity was 491.5, 490.5, 453.9, 418.1, 383.8, 333.1, and 294.4 mA h g-1 at 0.1, 0.2, 0.5, 1, 2, 5 and 10 A g-1, respectively. Furthermore, the MoS2/NSGs-G sample displayed lower resistance, dominant pseudocapacitive contribution, and faster sodium ion interface kinetics characteristic. Therefore, this study provides an operable strategy to obtain high-performance anode materials, and MoS2/NSGs-G with favorable structure and excellent cycle stability has great application potential for SIBs.

ZnSe@NPSC core-shell nanorods for super sodium ion storage induced from an organic polymer derived N, P, S tri-doped carbon framework.

In this work, core-shell structured ZnSe@NPSC nanorods were prepared with a N, P, S hetero-doped carbon shell. The design of the core-shell structure is conducive to facilitating the transport of electrons and buffering the volume expansion during charge/discharge processes, which is favourable for improving the sodium ion storage properties of ZnSe@NPSC. Therefore, it can deliver capacities of 376.67 mA h g-1 after 150 cycles at 0.5 A g-1 and 359.1 mA h g-1 after cycling for 350 cycles at 1.0 A g-1, respectively.

Tailoring the shell thickness of yolk–shell structured carbon microspheres: applications in metal selenide and carbon composite microspheres for enhanced sodium ion storage properties

Herein, synthesis of nanostructured carbon yolk–shell, which have various thicknesses of the outer shell, are introduced. The optimized nickel–cobalt selenide–carbon yolk–shell exhibited excellent performance as a sodium-ion battery anode material.

Decoration of carbon encapsulated nitrogen-rich MoxN with few-layered MoSe2 nanosheets for high-performance sodium-ion storage

Transition metal nitrides have become the focus of research in sodium ion batteries (SIBs) due to their unique metal properties and high theoretical capacity. However, the low actual capacity is still the main bottleneck for their application. Herein, using Mo-aniline frameworks as precursors, the carbon encapsulated nitrogen-rich MoxN is decorated by few-layered MoSe2 nanosheets (MoSe2@MoxN/C-I) after the facile calcinating, selenizing, and nitriding. The carbon encapsulation can effectively strengthen the structural stability of MoxN. The nitrogen-rich MoxN and decoration of few-layered MoSe2 can create rich heterointerfaces and extra active sites for rapid sodium-ion storage, thus promoting reaction kinetics and improving actual capacity. The MoSe2@MoxN/C-I as an anode achieves a large reversible capacity of 522.8 mAh g−1 at 0.1 A g−1, and 254.3 mAh g−1 capacity is obtained after 6000 cycles at 5.0 A g−1, showing signally improved sodium-ion storage properties. The storage mechanisms and kinetic behaviors are described systematically via the advanced testing techniques and density functional theory (DFT) calculations. It is found that the nitrogen-rich MoxN as the substrate is the basis of long cycling stability, and the few-layered MoSe2 are the key to improving actual capacity. This work indicates that the decoration of few-layered selenides has a broad application prospect in high-performance metal-ion batteries.

Optimized Co–S bonds energy and confinement effect of hollow MXene@CoS2/NC for enhanced sodium storage kinetics and stability

The sluggish kinetics and severe volume expansion are two major drawbacks that limiting the application of transition metal sulfides electrode materials for sodium ion batteries (SIBs). Herein, we assembled Ti3C2Tx MXene nanosheets into thin-walled hollow spheres with PMMA spheres as sacrificial template, on which MOF-derived CoS2 nanoparticles embedded in N-doped carbon were grown (MXene@CoS2/NC). The MXene@CoS2/NC exhibits state-of-the-art sodium ion storage properties, including a high reversible capacity of 620 mAh g−1 at 0.2 A g−1, superior rate capability (394 mAh g−1 at 5 A g−1), and excellent cycling stability (355 mAh g−1 after 5000 cycles). The corresponding electrochemical tests prove that the MXene@CoS2/NC has fast Na+ ion diffusion and electron transfer compared with its counterpart without MXene interfaces. XPS and XANES characterizations disclose the introduced MXene and increased pyrrolic N can weaken the Co-S bonds of CoS2, which facilitates the conversion reaction between CoS2 and Na2S, and thus improves the sodium storage kinetics. The DFT calculations also demonstrate the MXene can improve the conductivity of electrode materials by fast interfacial electron transfer. In addition, the MXene hollow spheres and MOF-derived NC provide host structures for CoS2, which can increase the contact between electrolyte and active materials, buffer the volume expansion of CoS2, and thus enhancing the electrochemical stability. This work provides a feasible strategy to construct anode materials for SIBs with improved sodium storage kinetics and cycling stability.

Investigation of the enhanced sodium ion storage properties of sphere-like NiS in ethers-based electrolyte

Investigation of the enhanced sodium ion storage properties of sphere-like NiS in ethers-based electrolyte

An insight into the sodium-ion and lithium-ion storage properties of CuS/graphitic carbon nitride nanocomposite.

Metal sulfides are gaining prominence as conversion anode materials for lithium/sodium ion batteries due to their higher specific capacities but suffers from low stability and reversibility issues. In this work, the electrochemical properties of CuS anode material has been successfully enhanced by its composite formation using graphitic carbon nitride (g-C3N4). The CuS nanoparticles are distributed evenly in the exfoliated g-C3N4 matrix rendering higher electronic conductivity and space for volume alterations during the repeated discharge/charge cycles. The 0.8CuS:0.2g-C3N4 composite when used as an anode for lithium ion coin cell exhibits a reversible capacity of 478.4 mA h g−1 at a current rate of 2.0 A g−1 after a run of 1000 cycles which is better than that reported for CuS composites with any other carbon-based matrix. The performance is equally impressive when 0.8CuS:0.2g-C3N4 composite is used as an anode in a sodium ion coin cell and a reversible capacity of 408 mA h g−1 is obtained at a current rate of 2.0 A g−1 after a run of 800 cycles. A sodium ion full cell with NVP cathode and 0.8CuS:0.2g-C3N4 composite anode has been fabricated and cycled for 100 runs at a current rate of 0.1 A g−1. It can be inferred that the g-C3N4 matrix improves the ion transfer properties, alleviates the volume alteration happening in the anode during the discharge/charge process and also helps in preventing the leaching of polysulfides generated during the electrochemical process.

Sodium-Ion Storage Properties of Thermally Stable Anatase

Anatase titanium dioxide (TiO 2 ) is a potential anode material for sodium-ion batteries (NIBs). However, the low electronic conductivity and sluggish ion diffusion kinetics at high rate hamper its practical applications. Herein, we demonstrate a sol-gel approach to the synthesis of thermally stable anatase nanoparticles with a carbon shell as anode materials for NIBs. A sample calcined at 750 °C (designated as H-750TiO 2 @C) exhibits high-rate capability and excellent stability against cycling with no capacity loss after 2000 cycles at 1 A g -1 . In situ X-ray diffraction and Raman spectroscopy characterization results reveal a nearly zero-strain characteristic of the anatase phase during charge/discharge processes. In situ transmission electron microscopy, ex situ X-ray photoelectron spectroscopy, and scanning electron microscope characterization results of samples collected at different charged and discharged states suggest that the anatase phase undergoes an irreversible sodiation-activation during the initial discharge process to form a sodiated-TiO 2 phase. A full cell assembled with H-750TiO 2 @C as the anode and Na 3 V 2 (PO 4 ) 3 as the cathode delivers an energy density of 220 Wh kg -1 , demonstrating H-750TiO 2 @C is a potential anode material for NIBs.

MoTe2 on metal-organic framework derived MoO2/N-doped carbon rods for enhanced sodium-ion storage properties

Sodium-ion batteries (SIBs) are highly potential for next-generation electrochemical energy storage because of their abundant resources and low prices. Transition metal dichalcogenides (TMDCs) have an excellent capacity, high electrical conductivity, and diverse structures. However, its volume expansion and tendency to restack during charge/discharge cycles lead to inferior electrochemical properties, limiting its development in the battery field. Herein, we synthesized MoO2/NC rods covered with MoTe2 nanosheets on the surface (MoTe2@MoO2/NC) by a high-temperature solid-phase synthesis method based on Mo-MOF a sacrificial template for sodium-ion batteries. The MoO2 core enhances the electron transfer efficiency as a conductive backbone and prevents the volume expansion of MoTe2 nanosheets. Meanwhile, the MoTe2 nanosheets are tightly wrapped around the MoO2 core, significantly reducing the ion diffusion path. Furthermore, the C and N doped substrates with conductivity ensure the integrity of the structure and enhance the conductivity of the electrodes. Benefiting from these advantages, MoTe2@MoO2/NC delivered a high electrochemical performance with high capacity (∼463.9 mAh g−1), superior fast-charge discharge ability (∼294.7, and 258.3 mAh g−1 at 5, and 10 A g−1, respectively). Even at a high current density of 1 A g−1, the specific capacity was maintained at about 328.3 mAh g−1 after 100 cycles.

Three-dimensional nitrogen-doped dual carbon network anode enabling high-performance sodium-ion hybrid capacitors

It is urgent for sodium-ion hybrid capacitors (SIHCs) to exploit a porous carbon anode that integrates high reversible specific capacity, rapid kinetics and superb cyclability. Herein, a three-dimensional dumpling-like glyururil-derived porous carbon@RGO composite (GLCG) constructed from nitrogen-doped (10.29 at.%) hierarchical porous carbon filling and highly conductive flexible RGO wrapper is synthesized. As for the Na half-cell, GLCG anode delivers high reversible specific capacity (282 mAhg-1 at 0.05 Ag−1) as well as superb rate capability (122.8 mAhg-1 at 10 Ag−1) and lifespan (3000 cycles at 2 Ag−1). Moreover, the origin of the excellent sodium-ion storage properties of GLCG is revealed by in-depth mechanism analysis. Consequently, a SIHCs with GLCG anode is constructed, which displays high energy density of 108 Wh kg−1, high power density of 14.2 kW kg−1 and long lifespan of 66% capacity retention after 5000 cycles at 2 Ag−1. This work provides an alternative avenue for the exploitation of high-performance carbon-based SIHCs anode.