Negative Electrode For Sodium-ion Batteries Research Articles

Oxidized Ti3Al(1-x)SnxC2 MAX phases as negative electrode materials for sodium ion batteries

Materials proposed for the negative electrodes in sodium-ion batteries often include oxides capable of reacting with Na+ through intercalation, conversion, or alloying. While these oxides offer high specific capacities, they suffer from poor mechanical stability. A novel approach to address this issue involves designing tailored nanocomposites based on the (Ti/Sn)Ox system, achieved through partial oxidation of tin-containing MAX phase (Ti3Al(1-x)SnxC2, x = 0.4 and 0.7). By employing this strategy, we have developed composite electrodes based on Ti(1-y)SnyO2 and MAX phase, which exhibit remarkable durability, withstanding over 600 cycles in half-cells. These electrodes also demonstrate charge efficiencies higher than 99.8 % and specific capacities comparable to MXenes electrodes. These outstanding electrochemical performances are further validated at the full-cell level when combined with Na0.44MnO2 positive electrodes. The reaction mechanism between the composite and the sodium ion was also studied using in-situ techniques (Raman and XAS) and the contribution of the different components during sodiation and de-sodiation was highlighted.

Structural and chemical analysis of hard carbon negative electrode for Na-ion battery with X-ray Raman scattering and solid-state NMR spectroscopy

This study explores the structural changes of hard carbon (HC) negative electrodes in sodium-ion batteries induced by insertion of Na ions during sodiation. X-ray Raman spectroscopy (XRS) was used to record both C and Na K-edge absorption spectra from bulk HC anodes carbonized at different temperatures and at several points during sodiation and desodiation. Comparing the π∗/σ∗ regions in the C K-edge spectra sp2/sp3 hybridization ratio of material was determined. Higher carbonization temperatures led to increased order in graphitic structure and shorter ▪ bond lengths. Sodiation caused a decrease in graphitic layer order due to inserted Na ions. Complementary operando solid state 23Na nuclear magnetic resonance (ssNMR) studies confirmed the structural changes, while showing pore filling mechanism, which is not observed in ex situ measurements, primarily at higher carbonization temperatures. XRS analysis of Na K-edge spectra revealed systematic variations in the solid electrolyte interface (SEI) composition during cycling. Changes in XRS spectra were attributed to both SEI composition alterations, accompanied by the insertion/adsorption of Na ions at defect sites within the carbon structure.

Tin-antimony/carbon composite porous fibers: electrospinning synthesis and application in sodium-ion batteries

In this work, tin-antimony/carbon composites porous fibers were successfully synthesized by an electrospinning method combined with two-step heat treatment processes, in which SnCl2 and SbCl3 were used as tin and antimony sources, and polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA) were used as binders and pore-forming agents. The as-synthesized tin-antimony/carbon composites were systematically characterized by x-ray Diffraction (XRD), Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM), Energy-Dispersive Spectrometer (EDS), x-ray Photoelectron Spectroscopy (XPS), and Thermogravimetric Analysis-Differential Scanning Calorimetry (TG-DSC). The results indicate that the composite material consists of one-dimensional nitrogen-doped carbon porous fibers as the main matrix, with a three-dimensional network structure in which Sn, SnO2, and SnSb particles are encapsulated. Furthermore, the tin-antimony/carbon composites porous fibers were utilized as self-supported negative electrode for sodium-ion batteries. The results showed that the SNbM-2 sample electrode calcined at 800 °C demonstrated the best cycling stability and rate capability among all the sample electrodes, with a discharge capacity of 319.5 mAh·g−1 maintained after 100 cycles at a current density of 0.1 A·g−1. The excellent electrochemical performance of the SNbM-2 sample electrode is benefited from its unique porous structure and the carbon fiber network structure encapsulating Sn, SnO2, and SnSb particles, which could effectively shorten the Na+ ion transport distance and mitigate electrode volume expansion.

Jute-Fiber Precursor-Derived Low-Cost Sustainable Hard Carbon with Varying Micro/Mesoporosity and Distinct Storage Mechanisms for Sodium-Ion and Potassium-Ion Batteries.

Hard carbon (HC) remains the most viable choice as a negative electrode for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) owing to its higher energy density (discharge up to zero volts), higher capacity (distinct storage mechanisms), and cycling stability. Herein, a biomass jute fiber precursor HC anode (JPC) with varying porosity is reported for the first time as a low-cost and sustainable high-performance HC anode for SIBs and PIBs. Direct carbonization results in micro-meso porous HC (JPC-D), and micro-wave pretreated jute fiber results in ultramicroporous HC (JPC-M). The mesoporosity generated in JPC-D during synthesis outperforms the ultramicroporous JPC-M with a high reversible capacity of 328 mAh g-1 (iCE = 66%) at a current density of 30 mA g-1 (0.1C) with superior capacity retention of 84% after 100 cycles in SIBs. The Na+ ion and K+ ion storage in HCs, especially at lower voltages, shows distinct storage mechanisms that depend on the morphology and porosity of the material. JPC-D contributed 39% of its total capacity through the plateau region capacity (PRC), suggesting more pore filling from hierarchical porosity in SIBs. JPC-D and JPC-M exhibit more insertion-based capacity than pore-filling processes in PIBs. The presence of inorganic impurities (Ca, Si, Al, and Fe) encapsulated in the carbon structure plays a critical role in developing mesopores. The yield (%) of HC from direct carbonization per kilogram of jute is ∼34%, which makes it cheaper than HC from sugar-based precursors and 1.5 times more affordable than other biomass-derived HC. The jute-based micro-mesoporous HC is a novel, cost-effective, sustainable approach to designing HC for a PRC-based battery-type anode in SIBs and PIBs.

NiS2 nanospheres coated by nitrogen-doped carbon for enhanced sodium storage performance

Nickel disulfide is used as anode material for sodium-ion batteries, with low cost, abundant reserves, and a wide variety of theoretical specific capacities as high as 870 mAh g−1. However, large volume expansion and low ionic conductivity during Na+ intercalation and deintercalation lead to poor electrochemical performance. This work has synthesized carbon layer-coated and N-doped NiS2 nanospheres through PVP-assisted hydrothermal and subsequent annealing processes, reducing volume expansion and improving electrical conductivity and Na+ storage activity, increasing ion diffusion kinetics during electrochemical charge-discharge in excellent specific capacity and cycle stability. When evaluated as a negative electrode for Sodium-ion batteries (SIBs), it exhibits excellent specific capacity (554.3 mAh g−1 at 0.2 A g−1, first-cycle coulombic efficiency of 92.3 %), and excellent long-cycle stability (436.3 mAh g−1 at 1 A g−1 for 800 cycles), demonstrating the potential of NiS2@NC as an ideal anode material for SIBs.

Laminar-protuberant like p-FeS2 rooted in mesoporous carbon sheets as high capacity anode for Na-ion batteries

Iron sulfide (FeS2) serves as tempting anode material for sodium-ion batteries (SIBs) owing to their higher theoretical specific capacity and truncated cost. However, the huge volume expansion during electrochemical cycling lowers the electro-conductivity and restricts their practical usage. In this study, a FeS2/carbon hybrid composite has been prepared through hydrothermal reaction and tested as a negative electrode for SIBs. The morphological analysis presents void betwixt p-FeS2 particles, ensuring structural reliability. X-ray photoelectron spectroscopy and X-ray absorption spectroscopy techniques are executed to examine the chemical environment and oxidation states for discharged/charged FeS2/C. When tested as an anode, the initial sodiation/desodiation capacity was recorded as 679/562 mAh g−1 at a rate of 0.05 C (where 1 C = 447 mA g−1). The rate performance of FeS2/C was evaluated in a range of 0.05–10.0 C where the material delivers a capacity of 319 mAh g−1 at 10.0 C. The FeS2/C composite exhibited an excellent Na storage capacity of 402 mAh g−1 after 200 cycles at 0.05 C with capacity retention and coulombic efficiency of 72% and 99.5%, respectively. The improved adsorption of Na-ions, good rate capacity and cycling stability is promoted from the synergistic interaction among FeS2 particles sited on the conductive sheets of mesoporous carbon matrix. Moreover, mesoporous carbon matrix is deemed responsible for better charge transfer and suppressing volume expansion during insertion/extraction cycles.

Sucrose–Thiourea-Derived Nitrogen and Sulfur Co-doped Hierarchically Porous Carbon Nanosheets as a High-Performance Negative Electrode for Sodium-Ion Batteries

Nitrogen-containing porous carbon derived from sucrose and thiourea by an environmentally friendly and economically feasible technique has been explored as a negative electrode for sodium-ion batte...

Na4Co3(PO4)2P2O7/NC Composite as a Negative Electrode for Sodium-Ion Batteries

Na₄Co₃(PO₄)₂P₂O₇/NC Composite as a Negative Electrode for Sodium-Ion Batteries

The effect of growth temperature on the process of insertion/extraction of sodium into germanium nanowires formed by electrodeposition using indium nanoparticles

In the present work negative electrodes for sodium-ion batteries, containing the arrays of germanium nanowires are prepared by electrodeposition from aqueous solution at different temperatures. Germanium nanowires have been deposited on titanium substrates with indium nanoparticles, which played the role of crystallization centers for germanium. The morphology and electrochemical performances of the nanowires are shown to be dependent on solution temperatures. It has been revealed that the presence of core–shell structure of the germanium nanowires (the presence of which is determined by the solution temperature) plays an important role in the Na insertion/extraction processes into Ge nanowires.

Nanostructured intermetallic InSb as a high-capacity and high-performance negative electrode for sodium-ion batteries

The paper reports the performance of a nanostructured InSb alloy as a promising negative electrode for sodium-ion batteries.

Tin selenide/N-doped carbon composite as a conversion and alloying type anode for sodium-ion batteries

Abstract Sodium-ion batteries (SIBs) have attracted remarkable attention since they are considered a low-cost alternative for lithium-ion batteries (LIBs) for large scale energy storage system applications. Tin selenides such as SnSe and SnSe2 are earth-abundant, environmentally friendly, chemically stable, and capable candidates as the negative electrode for SIBs, in which the capacity is provided by a conversion reaction together with the alloying mechanism. However, these materials suffer from low conductivity, drastic volume changes, and aggregation of particles during the electrochemical reaction, which lead to poor cycling performance, hindering their practical application. The combination of tin selenide with conductive carbon is an effective strategy to overcome the issues mentioned above. Herein, we report tin selenide/N-doped carbon composite as an anode material for SIBs fabricated by solvothermal synthesis followed by a dry solid state method and calcination. The as-prepared tin selenide/N-doped carbon composite electrode delivers an initial discharge capacity of 460 mAh g−1 and maintained a discharge capacity of 348 mAh g−1 at the end of the 100th cycle at a current density of 200 mA g−1, which is almost 3.5 times higher in discharge capacity than the pristine electrodes. Moreover, the composite electrode exhibits outstanding rate capability compared to pristine tin selenide with a discharge capacity of 234 mAh g−1 even at a high current density of 1600 mA g−1. N-doped carbon provides improved conductivity as well as buffering the volume change during sodiation/desodiation, resulting in an overall enhancement of electrochemical performance.

Electrochemistry of sodium titanate nanotubes as a negative electrode for sodium-ion batteries

Sodium-ion batteries are a promising alternative to lithium-ion devices, but the development of proper negative electrode materials is still challenging. Here, the properties of a low-voltage sodium titanate material are evaluated. Sodium titanate nanotubes (NTO) were produced by an alkalyne alkaline hydrothermal treatment with TiO2 and consisted of a hydrated Na1.4H0.6Ti3O7 with a surface area of 128 m2 g−1. NTO electrode kinetics were studied by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic intermittent titration techniques. The (de)intercalation of Na+ ions involved two redox pairs at 0.3/0.5 V and 1.0/1.2 V, associated with the present mixture of nanotubes and nanosheets. Surface processes had a 95% coulombic efficiency and a high contribution even at low scan rates, accounting for 47% of the total capacity at 0.5 mV s−1. Upon Na+ removal, the electronic resistance and the semiconductor capacitance increased. Battery tests performed on Na|NTO half-cells showed a reversible capacity of 90 mA h g−1 at 10 mA g−1 and near 100% coulombic efficiency at current rates ranging from 10 mA g−1 to 10 A g−1. Additionally, NTO presented a good capacity retention of 92% after 170 cycles at 100 mA g−1.

Sodium Naphthalene-2,6-dicarboxylate: An Anode for Sodium Batteries.

The conjugated dicarboxylate sodium naphthalene-2,6-dicarboxylate (Na2 NDC) was prepared by a low-energy-consumption reflux method, and its performance as a negative electrode for sodium-ion batteries was evaluated in electrochemical cells. The structure of Na2 NDC was solved for the first time (monoclinic P21 /c) from powder XRD data and consists of π-stacked naphthalene units separated by sodium-oxygen layers. Through an appropriate choice of binder and conducting carbon additive, Na2 NDC exhibited a reversible two electron sodium insertion at approximately 0.4 V (vs. Na+ /Na) with remarkably stable capacities of approximately 200 mAh g-1 at a rate of C/2 and good rate capability (≈133 mAh g-1 at 5 C). In parallel, the high thermal stability of the material was demonstrated by high-temperature XRD: the framework remained intact to above 500 °C.

(Invited) Carbon Fiber-Paper–Supported Carbon Nanofoams As Free-Standing Electrode Architectures for Reversible Sodium-Ion Storage

Hard (non-graphitizable) carbon has emerged as a prospective charge-storage material for negative electrodes in sodium-ion batteries, yet reported electrochemical performance across this broad category of carbons varies widely. Such discrepancies arise in part due to the multiple distinct sodiation reactions that are possible with disordered carbon electrodes, whereby sodium ions can be stored in defect sites, graphitic layers, and/or micropores depending on the pore–solid architecture, surface chemistry, and solid-state structure of a particular carbon. To address both fundamental questions and practical application in Na-ion batteries, we are investigating carbon nanofoam papers (CNFPs), synthesized by infiltrating the voids of carbon-fiber paper with resorcinol–formaldehyde (R–F) formulations to form porous polymer nanofoam that is subsequently converted to the conductive carbon analog via pyrolysis at 1000°C [1]. When tested as free-standing electrode architectures in Na-ion cells, CNFPs deliver specific capacity >300 mAh g–1 at a 1C rate and >250 mAh g–1 at 10C, with a first-cycle Coulombic efficiency near 85% under galvanostatic operation. The galvanostatic intermittent titration technique (GITT) confirms that Na-ion diffusion is facile in the defect-mediated charge-storage regime. We attribute these favorable properties to the high defect concentration in the disordered R–F-derived carbon domains, the 3D-interconnected porosity within the carbon nanofoam, and the absence of otherwise-necessary binder and conductive additives that are commonly used in conventional powder-composite electrodes. Our results demonstrate the utility of CNFPs as device-ready, self-supported electrodes and advance the design of related carbon materials for next-generation Na-ion batteries. [1] J.C. Lytle, J.M. Wallace, M.B. Sassin, A.J. Barrow, J.W. Long, J.L. Dysart, C.H. Renninger, M.P. Saunders, N.L. Brandell, and D.R. Rolison, Energy Environ. Sci., 4 (2011) 1913–1925.

Vanadium phosphide–phosphorus composite as a high-capacity negative electrode for sodium secondary batteries using an ionic liquid electrolyte

A vanadium phosphide–phosphorus composite, V4P7/5P, is investigated as a negative electrode for sodium-ion batteries using the ionic liquid, Na[FSA]–[C3C1pyrr][FSA] (FSA = bis(fluorosulfonyl)amide anion and C3C1pyrr = N-methyl-N-propylpyrrolidinium cation), as the electrolyte. Analyses of the X-ray diffraction pattern, X-ray photoelectron spectra, and transmission electron microscopy images revealed that the V4P7/5P composite prepared by high-energy ball-milling is composed of a V4P7 crystalline phase and an amorphous phosphorus phase. This composite exhibits a high reversible discharge capacity of 738 mAh g−1, with a reasonably high initial coulombic efficiency of 85.9% at 363 K, even in the absence of carbon materials. The emergence of Na3P peaks in the ex situ XRD pattern after full charging indicated sodiation of the excess amorphous phosphorus present in the composite. The peaks corresponding to V4P7 remained intact and desodiation of Na3P after full discharge was also evident from the XRD pattern. The cyclability was higher in the ionic liquid electrolyte than in an organic electrolyte owing to the formation of a more efficient interfacial layer in the former.

V2O5·nH2O nanosheets and multi-walled carbon nanotube composite as a negative electrode for sodium-ion batteries

Two dimensional (2D) transition metal oxides and chalcogenides demonstrate a promising performance in sodium-ion batteries (SIBs) application. In this study, we investigated the use of a composite of freeze dried V2O5·nH2O nanosheets and multi-walled carbon nanotube (MWCNT) as a negative electrode material for SIBs. Cyclic voltammetry (CV) results indicated that a reversible sodium-ion insertion/deinsertion into the composite electrode can be obtained in the potential window of 0.1–2.5 V vs. Na+/Na. The composite electrodes delivered sodium storage capacities of 140 and 45 mAh g−1 under applied current densities of 20 and 100 mA g−1, respectively. The pause test during constant current measurement showed a raise in the open circuit potential (OCP) of about 0.46 V, and a charge capacity loss of ∼10%. These values are comparable with those reported for hard carbon electrodes. For comparison, electrodes of freeze dried V2O5·nH2O nanosheets were prepared and tested for SIBs application. The results showed that the MWCNT plays a significant role in the electrochemical performance of the composite material.

High-capacity FeTiO3/C negative electrode for sodium-ion batteries with ultralong cycle life

The development of electrode materials which improve both the energy density and cycle life is one of the most challenging issues facing the practical application of sodium-ion batteries today. In this work, FeTiO3/C nanoparticles are synthesized as negative electrode materials for sodium-ion batteries. The electrochemical performance and charge-discharge mechanism of the FeTiO3/C negative electrode are investigated in an ionic liquid electrolyte at 90 °C. The FeTiO3/C negative electrode delivers a high reversible capacity of 403 mAh g−1 at a current rate of 10 mA g−1, and exhibits high rate capability and excellent cycling stability for up to 2000 cycles. The results indicate that FeTiO3/C is a promising negative electrode material for sodium-ion batteries.

Nanostructured Na2Ti9O19 for Hybrid Sodium-Ion Capacitors with Excellent Rate Capability.

Herein, we report a new Na-insertion electrode material, Na2Ti9O19, as a potential candidate for Na-ion hybrid capacitors. We study the structural properties of nanostructured Na2Ti9O19, synthesized by a hydrothermal technique, upon electrochemical cycling vs Na. Average and local structures of Na2Ti9O19 are elucidated from neutron Rietveld refinement and pair distribution function (PDF), respectively, to investigate the initial discharge and charge events. Rietveld refinement reveals electrochemical cycling of Na2Ti9O19 is driven by single-phase solid solution reaction during (de)sodiation without any major structural deterioration, keeping the average structure intact. Unit cell volume and lattice evolution on discharge process is inherently related to TiO6 distortion and Na ion perturbations, while the PDF reveals the deviation in the local structure after sodiation. Raman spectroscopy and X-ray photoelectron spectroscopy studies further corroborate the average and local structural behavior derived from neutron diffraction measurements. Also, Na2Ti9O19 shows excellent Na-ion kinetics with a capacitve nature of 86% at 1.0 mV s-1, indicating that the material is a good anode candidate for a sodium-ion hybrid capacitor. A full cell hybrid Na-ion capacitor is fabricated by using Na2Ti9O19 as anode and activated porous carbon as cathode, which exhibits excellent electrochemical properties, with a maximum energy density of 54 Wh kg-1 and a maximum power density of 5 kW kg-1. Both structural insights and electrochemical investigation suggest that Na2Ti9O19 is a promising negative electrode for sodium-ion batteries and hybrid capacitors.

Hydrothermally synthesized tin (IV) sulfide as a negative electrode for sodium-ion batteries and its sodiation mechanism

A hydrothermally synthesized tin (IV) sulfide electrode was examined for use as a negative electrode in sodium-ion batteries. Using ex-situ XRD and electrochemical analysis, the sodiation mechanism of tin (IV) sulfide was clarified, which revealed that the typical conversion reaction-coupled alloying reaction happened during sodiation with a high reversible capacity (~640mAhg−1). Also, the improved cycleability was observed in the tin (IV) sulfide electrode when compared with tin metal electrode. From comparison of quasi-open-circuit voltages at the 20th de-sodiated electrode, it was revealed that sodium trapping was considerably suppressed by sulfide formation with tin.

Unusual Passivation Ability of Superconcentrated Electrolytes toward Hard Carbon Negative Electrodes in Sodium-Ion Batteries.

The passivation of negative electrodes is key to achieving prolonged charge-discharge cycling with Na-ion batteries. Here, we report the unusual passivation ability of superconcentrated Na-salt electrolytes. For example, a 50 mol % sodium bis(fluorosulfonyl)amide (NaFSA)/succinonitrile (SN) electrolyte enables highly reversible Na+ insertion into a hard carbon negative electrode without any electrolyte additive, functional binder, or electrode pretreatment. Importantly, an anion-derived passivation film is formed via preferential reduction of the anion upon charging, which can effectively suppress further electrolyte reduction. As a structural characteristic of the electrolyte, most anions are coordinated to multiple Na+ cations at high concentration, which shifts the lowest unoccupied molecular orbitals of the anions downward, resulting in preferential anion reduction. The present work provides a new understanding of the passivation mechanism with respect to the coordination state of the anion.