Application In Sodium-ion Batteries Research Articles

Carbon-Reinforced Nb2CTx MXene/MoS2 Nanosheets as a Superior Rate and High-Capacity Anode for Sodium-Ion Batteries.

Sodium-ion batteries operating at room temperature have emerged as a generation of energy storage devices to replace lithium-ion batteries; however, they are limited by a lack of anode materials with both an adequate lifespan and excellent rate capability. To address this issue, we developed Nb2CTx MXene-framework MoS2 nanosheets coated with carbon (Nb2CTx@MoS2@C) and constructed a robust three-dimensional cross-linked structure. In such a design, highly conductive Nb2CTx MXene nanosheets prevent the restacking of MoS2 sheets and provide efficient channels for charge transfer and diffusion. Additionally, the hierarchical carbon coating has a certain level of volume elasticity and excellent electrical conductivity to guarantee the intercalation of sodium ions, facilitating both fast kinetics and long-term stability. As a result, the Nb2CTx@MoS2@C anode delivers an ultrahigh reversible capacity of 530 mA h g-1 at 0.1 A g-1 after 200 cycles and very long cycling stability with a capacity of 403 mA h g-1 and only 0.01% degradation per cycle for 2000 cycles at 1.0 A g-1. Moreover, this anode has an outstanding capacity retention rate of approximately 88.4% from 0.1 to 1 A g-1 in regard to rate performance. Most importantly, the Nb2CTx@MoS2@C anode can realize a quick charge and discharge at current densities of 20 or even 40 A g-1 with capacities of 340 and 260 mAh g-1, respectively, which will increase the number of practical applications for sodium-ion batteries.

Na3V2(PO4)3/C·Na3V2(PO4)2F3/C@rGO blended cathode material with elevated energy density for sodium ion batteries

Na3V2(PO4)3 (NVP), a promising cathode material of sodium ion batteries, has gained much attention due to its competitive capability of sodium storage. However, the relatively low discharge potential of ~3.4 V (vs. Na+/Na) needs to be improved and the current energy density cannot satisfy the practical applications. Herein, the introduction of Na3V2(PO4)2F3 with high voltage plateaus is adopted to elevate the energy density. Therefore, the mixed composite seems to be more attractive because of the prospective high energy character. Nevertheless, this mixture still suffers from the intrinsic poor electronic conductivity. Accordingly, a novel Na3V2(PO4)3/C·Na3V2(PO4)2F3/C @reduced graphene oxide (rGO) (denoted as B@rGO) blended cathode material is successfully synthesized through a facile sol-gel method. The coated carbon layers and rGO are employed to construct a conductive network for promoting the ionic and electronic diffusion efficiently. Detailed kinetic analyses demonstrate that the NVP phase dominates the kinetic reaction in the blended composite. With respect to the electrochemical properties, this modified B@rGO composite can deliver a discharge capacity of 115.1 mAh g-1 at 0.1 C, corresponding to a high energy density of 418.3 Wh kg-1, which is far more than the theoretical one of pure NVP (399.8 Wh kg-1). Moreover, the cyclic characteristics are significantly improved, resulting from the boosted structural stability. Even at a high rate of 30 C, it can release a reversible capacity of 85.9 mAh g-1, and a high capacity retention of 81.6% is obtained after 200 cycles. Furthermore, the superior electrochemical properties are determined and demonstrated by the improved kinetics, including the large capacitive contribution (79.6% at 0.5 mV s-1) and rapid ionic migration. Therefore, this novel co-modification strategy with high-voltage material and conductive rGO can be an efficient way for Na3V2(PO4)3 to optimize the electrochemical performance and push its application in sodium ion batteries.

MXene-Based Materials for Electrochemical Sodium-Ion Storage.

Advanced architecture and rational design of electrode materials for electrochemical sodium‐ion storage are well developed by researchers worldwide. MXene‐based materials are considered as one of the most potential electrode materials for sodium‐ion‐based devices, such as sodium‐ion batteries (SIBs), sodium–sulfur batteries (SSBs), and sodium‐ion capacitors (SICs), because of the excellent physicochemical characteristics of MXenes. Here, in this review, the recent research work and progress, both theoretical and experimental, on MXene‐based materials including pure MXenes and MXene‐based composites in application of SIBs, SSBs, and SICs are comprehensively summarized. The sodium storage mechanisms and the effective methods to enhance the electrochemical performance are also discussed. Finally, the current critical challenges and future research directions on the development of these MXene‐based materials for electrochemical sodium‐ion storage are presented.

Gel-Polymer Electrolytes for Sodium Batteries - Raman and Electrochemical Impedance Spectroscopic Studies

Sodium-ion batteries (SIBs) as low-cost alternatives to expensive lithium-ion batteries become a hot R&D topic in the recent days due to the natural abundancy of sodium in the Earth’s crust and also in the oceans. As far as solid electrolytes for SIBs are concerned, larger size of Na+ ions compared to that of Li+ ions hinders the ionic mobility resulting to insufficient ionic conductivity for practical applications. Development of quasi-solid state gel-polymer electrolytes (GPEs) would be a feasible solution to overcome this challenge. In this work, we developed Poly (methyl methacrylate) (PMMA) based GPEs with six different compositions dissolved in EC:PC (ethylene carbonate and propylene carbonate, 1:1 wt%) mixture. Among six different GPE samples investigated by Electrochemical Impedance Spectroscopic and Raman Spectroscopic techniques, the best ambient temperature ionic conductivity of 4.2 mS cm-1 was obtained for 9PMMA:9NaPF6:41EC:41PC (wt%). Variation of ionic conductivity with inverse temperature showed Arrhenius behavior with almost constant activation energies. The best conducting GPE showed an activation energy of 0.14 eV. In the Raman spectra, very sharp crystalline peaks (400-850 cm-1 wave number range) of NaPF6 disappear in the gel state of the electrolytes confirming the non-crystalline nature of the GPEs. Boson modes remain almost constant in intensity for all the six different compositions. The best conducting GPE seems to be highly suitable for practical applications in SIBs as it has sufficient ambient temperature ionic conductivity.

A review of niobium oxides based nanocomposites for lithium-ion batteries, sodium-ion batteries and supercapacitors

Batteries and hybrid supercapacitors (SCs) are now playing a pivotal role in the development of electric vehicles, consumer electronics and large-scale power stations. Niobium-oxides-based materials and their composites have recently received a great attention for their applications in lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), and pseudocapacitors because of their advantages, such as quasi-2D networks for fast ion insertion/extraction, rich redox chemistry, and high chemical stability. However, several challenges, including poor inherent conductivities and limited/superficial electrochemical active sites, should be overcome before practical applications. In this paper, the recent advancement of the materials preparation, synthesis, characterization, and performance validation as well as fundamental understanding of the functional mechanisms are comprehensively reviewed. Several technical challenges and strategies are respectively analyzed and utilized to improve the materials’ electrochemical performances, including morphology control, surface engineering, doping and construction of composite electrodes. Indeed, the charge storage mechanisms of the materials with different crystal structures are summarized and discussed. Several research directions toward the development, practical applications and commercialization of the related electrochemical energy devices are also proposed for enhancing the performance of niobium oxides and their composites. • Key strategy for improving electrochemical performance of Nb 2 O 5 -based materials is proposed. • Strategy developing Nb 2 O 5 -based materials with high performance is proposed. • An insight into the future research direction of Nb 2 O 5 -based materials is highlighted.

Atomic Layer Coated Al2O3 on Nitrogen Doped Vertical Graphene Nanosheets for High Performance Sodium Ion Batteries

Heteroatom doped graphene materials are considered as promising anode for high‐performance sodium‐ion batteries (SIBs). Defective and porous structure especially with large specific surface area is generally considered as a feasible strategy to boost reaction kinetics; however, the unwanted side reaction at the anode hinders the practical application of SIBs. In this work, a precisely controlled Al2O3 coated nitrogen doped vertical graphene nanosheets (NVG) anode material has been proposed, which exhibits excellent sodium storage capacity and cycling stability. The ultrathin Al2O3 coating on the NVG is considered to help construct an advantageous interface between electrode and electrolyte, both alleviating the electrolyte decomposition and enhancing sodium adsorption ability. As a result, the optimal Al2O3 coated NVG materials delivers a high reversible capacity (835.0 mAh g−1) and superior cycling stability (retention of 92.3% after 5000 cycles). This work demonstrates a new way to design graphene‐based anode materials for high‐performance sodium‐ion batteries.

A Review of the Synthesis, Properties, and Applications of Bulk and Two-Dimensional Tin (II) Sulfide (SnS)

Tin(II) sulfide (SnS) is an attractive semiconductor for solar energy conversion in thin film devices due to its bandgap of around 1.3 eV in its orthorhombic polymorph, and a band gap energy of 1.5–1.7 eV for the cubic polymorph—both of which are commensurate with efficient light harvesting, combined with a high absorption coefficient (10−4 cm−1) across the NIR–visible region of the electromagnetic spectrum, leading to theoretical power conversion efficiencies >30%. The high natural abundance and a relative lack of toxicity of its constituent elements means that such devices could potentially be inexpensive, sustainable, and accessible to most nations. SnS exists in its orthorhombic form as a layer structure similar to black phosphorus; therefore, the bandgap energy can be tuned by thinning the material to nanoscale dimensions. These and other properties enable SnS applications in optoelectronic devices (photovoltaics, photodetectors), lithium- and sodium-ion batteries, and sensors among others with a significant potential for a variety of future applications. The synthetic routes, structural, optical and electronic properties as well as their applications (in particular photonic applications and energy storage) of bulk and 2D tin(II) sulfide are reviewed herein.

High Stability and Long Cycle Life of Rechargeable Sodium-Ion Battery Using Manganese Oxide Cathode: A Combined Density Functional Theory (DFT) and Experimental Study.

Sodium-ion batteries (SIBs) can develop cost-effective and safe energy storage technology for substantial energy storage demands. In this work, we have developed manganese oxide (α-MnO2) nanorods for SIB applications. The crystal structure, which is crucial for high-performance energy storage, is examined systematically for the metal oxide cathode. The intercalation of sodium into the α-MnO2 matrix was studied using the theoretical density functional theory (DFT) studies. The DFT studies predict Na ions’ facile diffusion kinetics through the MnO2 lattice with an attractively low diffusion barrier (0.21 eV). When employed as a cathode material for SIBs, MnO2 showed a moderate capacity (109 mAh·g–1 at C/20 current rate) and superior life cyclability (58.6% after 800 cycles) in NaPF6/EC+DMC (5% FEC) electrolyte. It shows a much higher capacity of 181 mAh·g–1 (C/20 current rate) in NaClO4/PC (5% FEC) electrolyte, though it suffers fast capacity fading (11.5% after 800 cycles). Our findings show that high crystallinity and hierarchical nanorod morphology of the MnO2 are responsible for better cycling performance in conjunction with fast and sustained charge-discharge behaviors.

Ternary transition metal chalcogenides Ti2PX2 (X = S, Se, Te) anodes for high performance metal-ion batteries: A DFT study

Two-dimensional (2D) materials display special interest as for metal-ion batteries (MIBs) due to they have high specific surface area and unique electrochemical activity. Here, interactions between ternary transition metal chalcogenides Ti2PX2 (X = S, Se, Te) and metal-ion (Li, Na, K and Ca) are theoretically studied via density functional theory (DFT) calculations. Their metal-ion storage capabilities are systematically explored and compared with available experimental and theoretical information. Ti2PX2Li2 and Ti2PX2K2 exhibit the same storage capacity (281 mAhg−1), however K shows lower diffusion barrier (~0.07 eV) than Li (~0.17–0.21 eV). Although Ca shows significant large capacity (842–1685 mAhg−1), its diffusion barrier is higher than other ions. The small change in lattice parameter (Ti2PX2Na6: <1.2%), high capacity (842 mAhg−1 up to Ti2PX2Na6), low open circuit voltage (0.4–0.6 V) and low diffusion barrier energy (~0.1 eV) are found in Ti2PX2 for sodium-ion adsorption. These properties are superior as compared to other available 2D materials, such as graphene, MXenes (Ti3C2), MoS2 and so on. Our results indicate that Ti2PX2 monolayers may be promising for MIBs anode materials, especially for sodium-ion batteries (SIBs) applications.

Analysis of the Ordering Effects in Anthraquinone Thin Films and Its Potential Application for Sodium Ion Batteries.

The ordering effects in anthraquinone (AQ) stacking forced by thin-film application and its influence on dimer solubility and current collector adhesion are investigated. The structural characteristics of AQ and its chemical environment are found to have a substantial influence on its electrochemical performance. Computational investigation for different charged states of AQ on a carbon substrate obtained via basin hopping global minimization provides important insights into the physicochemical thin-film properties. The results reveal the ideal stacking configurations of the individual AQ-carrier systems and show ordering effects in a periodic supercell environment. The latter reveals the transition from intermolecular hydrogen bonding toward the formation of salt bridges between the reduced AQ units and a stabilizing effect upon the dimerlike rearrangement, while the strong surface–molecular interactions in the thin-film geometries are found to be crucial for the formed dimers to remain electronically active. Both characteristics, the improved current collector adhesion and the stabilization due to dimerization, are mutual benefits of thin-film electrodes over powder-based systems. This hypothesis has been further investigated for its potential application in sodium ion batteries. Our results show that AQ thin-film electrodes exhibit significantly better specific capacities (233 vs 87 mAh g–1 in the first cycle), Coulombic efficiencies, and long-term cycling performance (80 vs 4 mAh g–1 after 100 cycles) over the AQ powder electrodes. By augmenting the experimental findings via computational investigations, we are able to suggest design strategies that may foster the performance of industrially desirable powder-based electrode materials.

Sycamore fruit seed‐based hard carbon anode material with high cycle stability for sodium‐ion battery

Hard carbon is considered to be one of the most promising anodes for sodium-ion batteries (SIBs), but high cost and poor cycle stability limit the large-scale application for SIBs. Here, a new kind of low-cost sycamore fruit seed hard carbon was prepared by facile pyrolysis at different temperatures as anode for SIBs. With the large interlayer spacing, the reversible specific capacity of sycamore fruit seed carbonized at 1100 °C can reach 323 mAh g−1 at the current density of 0.1 C. When cycled at 0.4 C, the reversible specific capacity is 246.9 mAh g−1, following the capacity retention is 87.85% after 300 cycles. Moreover, we find although the different interlayer spacings (d002 ≥ 0.37 nm) of graphite crystallites of the obtained hard carbon beneficial for the Na+ storage, the smaller d002 limits the diffusion of Na+ inevitably, which affects their cycle stability. This research furnishes a competitive choice about anode materials for the industrialized SIBs.

Carbon coated NaLi0.2Mn0.8O2 as a superb cathode material for sodium ion batteries

P2 structure materials have been known as a promising cathode material for sodium ion battery. However, their substandard rate capability is a major obstacle for the application of sodium ion batteries to overcome. Herein, we improved the rate capacity of the P2-type sodium-lithium-manganese oxide material by a carbon additive on the material surface. The structure and morphology of pristine sodium-lithium-manganese oxide (NLM) and carbon-coated sodium-lithium-manganese oxide (NLM@C) were confirmed by X-ray diffraction (XRD), Raman spectra, thermal gravimetric analysis (TGA), scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), and transmission electron microscopy (TEM). The electrochemical results revealed that the carbon coating improves rate capability of NLM@C material and increases its specific capacity. Specifically, the NLM@C material delivered a specific capacity of 160 mAh g−1 at 0.1 C, ca. 33% higher than that of pristine NLM material; the NLM@C material retained a capacity of 115 mAh g−1 at a high charged/discharged rate of 1 C. The result suggests that NLM@C material is a promising cathode material for sodium-ion battery applications.

Preparation of SnS2/enteromorpha prolifera derived carbon composite and its performance of sodium-ion batteries

SnS2 has aroused great interests for application of sodium-ion batteries, because of its graphene-like structure and high theoretical capacity. Herein, we present an effective nanocasting strategy to fabricate the SnS2/enteromorpha prolifera derived carbon (SnS2/EPC) composite, whose microstructure anchors the SnS2 nanosheets on enteromorpha prolifera (EP) derived carbon. It can effectively solve the problems of poor conductivity and volume expansion of SnS2 electrode during charging and discharging process. The optimized SnS2/EPC could deliver high reversible capacity of 443 mA h g−1 at 0.1 A g−1, and maintain reversible capacity of 340 mA h g−1 at high rate of 2 A g−1 after 450 cycles, indicating that SnS2/EPC is a promising anode material for sodium storage.

Maximized pseudo-graphitic content in self-supported hollow interconnected carbon foam boosting ultrastable Na-ion storage

Hard carbons are the most promising commercialized anodes for sodium-ion batteries (SIBs). However, it is still a great challenge to design highly stable hard carbon anodes coupled with a large reversible capacity. Herein, a self-supported hollow interconnected carbon foam (HICF) is developed by one-step pyrolysis of a commercial and low-cost melamine sponge. The integration of interconnected network and hollow feature can not only provide strong mechanical stability and additional inner space to effectively accommodate the structural deformation from Na+ insertion/extraction, but also enable fast electron and Na-ion transport to achieve a large reversible capacity. As a result, HICF delivers a large reversible capacity of 306 mAh g−1 at 100 mA g−1 and an ultralong cycle life with 86.4% capacity retention over 1000 cycles at 1000 mA g−1. The superior Na-storage performance is also contributed by the maximized content (63.24%) of pseudo-graphitic phase in HICF realized by tuning pyrolysis time, as the pseudo-graphitic phase could store more sodium ions and maintain more stable microstructure owing to its appropriate d-spacing than highly disordered phase. Furthermore, kinetic analysis based on cyclic voltammetry (CV) and galvanostatic intermittent titration technique (GITT) verifies the adsorption–intercalation mechanism. This work provides a low-cost and high-performance anode candidate for the future practical applications of SIBs.

Graphether: a reversible and high-capacity anode material for sodium-ion batteries with ultrafast directional Na-ion diffusion.

Sodium-ion batteries (SIBs) have been attracting great attention as the most promising alternative to lithium-ion batteries (LIBs) for large-scale energy storage. However, the absence of suitable anode materials is the main bottleneck for the commercial application of SIBs. Herein, the adsorption and diffusion behaviors of Na on graphether are predicted by first-principles density functional calculations. Our results show that Na atoms can be adsorbed on graphether forming a uniform and stable coverage on both sides. Even at low intercalated Na concentrations, the semiconducting graphether can be changed to a metallic state, ensuring good electrical conductivity. Due to the structural anisotropy of graphether, the Na+ ions show a remarkable one-dimensional diffusion with an ultralow energy barrier of 0.04 eV, suggesting ultrafast charge/discharge characteristics. The graphether monolayer has a high theoretical specific capacity of 670 mA h g-1, which is much higher than commercial graphite anode materials. Furthermore, the average voltage is 1.58 V, comparable with that of commercial TiO2 anode materials for LIBs (1.5 V). During the charge/discharge process, graphether could mostly preserve the structural integrity upon the adsorption of Na even at the maximum concentration, suggesting its good reversibility. All these results show that graphether is a promising anode material for high-performance SIBs.

Boost sodium-ion batteries to commercialization: Strategies to enhance initial Coulombic efficiency of hard carbon anode

Sodium-ion batteries (SIBs) are regarded as one of the most promising candidates for large-scale energy storage system due to low cost and inexhaustible sodium reserves. The commercialize application of SIBs relies on the development of advanced cathode and anode materials. Among the various available anode materials, hard carbon material is considered to be the most potential anode material, which presents appropriate sodiation/desodiation electric potential, high capacity, and simple synthesis method. However, the insufficient initial Coulombic efficiency (ICE) of hard carbon severely restricts the practical commercialization in SIBs. Hence, we review the influence elements that cause an inadequate ICE of hard carbon, such as the decomposition of electrolytes, high defects concentration, excessive surface functional groups, and irreversible sodium ions and so on. In order to obtain a moderate ICE, strategies including structure and morphology modification, defect and surface engineering, composition adjustment, electrolyte and binder optimization, material pre-treatment are confirmed to be effective. This review provides a further understanding of obtaining hard carbon electrodes with high ICE, which will contribute to the prosperity of SIBs in the near future.

Carbon Nanofibers with Embedded Sb2 Se3 Nanoparticles as Highly Reversible Anodes for Na-Ion Batteries.

As a promising candidate for large-scale energy storage, sodium-ion batteries (SIBs) have superiority due to their low cost and abundance as a resource. Herein, homogeneous Sb2 Se3 nanocrystallites embedded in carbon nanofibers (Sb2 Se3 /CNFs) by electrospinning and selenization treatment are prepared. The obtained Sb2 Se3 /CNFs exhibit good cycling performance, high reversible capacity, and excellent rate capability as anodes for SIBs. The outstanding performances are attributed to a combination of Na+ intercalation, conversion reaction, and alloying with Sb2 Se3 , disclosed through in-situ X-ray diffraction. Meanwhile, unique nanostructures provide large contact surface and tolerant accommodation to volume expansion which bring high reversibility and long cycle durability. This distinctive material shows prospective applications of SIBs especially under high current density.

Monitoring the Sodiation Mechanism of Anatase TiO2 Nanoparticle-Based Electrodes for Sodium-Ion Batteries by Operando XANES Measurements

Anatase TiO2 represents an attractive electrode material for application in sodium-ion batteries due to its relatively low cost, high environmental compatibility, high intrinsic safety, conferred b...

Improved Na storage performance of Na3V2(PO4)3 cathode material for sodium-ion batteries by K-Cl co-doping

As a promising cathode material for sodium-ion batteries (SIBs), Na3V2(PO4)3 (NVP), the typical NASICON (Na super-ionic conductor)-structure cathode material, has received much attention resulting from its high working potential and excellent structural stability. However, it has always suffered from low electroconductivity, which largely limits its application in SIBs. Herein, to improve the electrochemical performance, we developed potassium and chlorine co-doped Na3V2(PO4)3/carbon particles (NKVPCl/C) using a spray-drying method combined with a calcinating process and adopted them as cathode materials for SIBs. We studied in detail how K+ and Cl− affected the electrochemical performance. The NKVPCl/C-2 particles displayed a highly initial discharge capacity of 109.6 mA h g−1 at 0.2 C, and had a superior cycling stable property (nearly 100% of initial discharge capacity after 500 cycles at 5 C). The excellent electrochemical performance of NKVPCl/C can be attributed to its higher Na+ diffusion and electron conduction, which indicates that the strategy of co-doping K-Cl is an effective tactic for improving the property of NVP in SIBs.

CuCo2S4: Versatile anode for high capacity and high rate for lithium and sodium ion battery application

In an attempt to exploit ternary metal sulfides as high energy and high power anode material for lithium and sodium ion batteries, in-house prepared CuCo2S4 (CCS) nanoparticles, obtained through template free one pot solvothermal synthesis has been deployed. Herein, particle size of CCS obtained below 50 nm helps to address two main challenges such as capacity fading and inferior rate capability behavior. Further, we demonstrate the composite of CCS consisting of multi-walled carbon nanotube (MWCNT) in the form of CCS/MWCNT as potential anode for LIBs and SIBs. While pristine CCS delivers a specific capacity of 934 mA h g−1 at 50 mA g−1 even after 50 cycles, the CCS/MWCNT anode exhibits an appealing capacity of 1300 mA h g−1 for 200 cycles at 500 mA g−1 and 1700 mA h g−1 at 100 mA g−1 for 50 cycles in LIBs. Similarly, CCS/MWCNT anode exhibits 181 mA h g−1 and 236 mA h g−1 at 5 and 1 A g−1 respectively upto 500 cycles in SIBs with 90 and 95% capacity retention, which is noteworthy. CCS/MWCNT anode tolerates up to 20 A g−1 current density and delivers a capacity of 87 mA h g−1, thus qualifying itself as the versatile anode for application in LIBs and SIBs.