Sodium-ion Storage Performance Research Articles

Boosting potassium and sodium-ion storage performance by in-situ self-assembly of a Co-based π-d conjugated coordination polymer on graphene nanosheets

To obtain anode materials with good electrochemical performances in both potassium ion batteries (PIBs) and sodium-ion batteries (SIBs), a Co-based π-d conjugated coordination polymer (Co-HHTP) is in-situ assembled on graphene (G) nanosheets using a facile one-step solvothermal method. The resulting Co-HHTP/G composite shows improved electrochemical performances over pure Co-HHTP. After 300 cycles of using as an anode of PIBs/SIBs for the first time, the reversible specific capacity of the Co-HHTP/G composite is found to be 381/277 mAh g−1 at 100 mA g−1. After undergoing 500 cycles at 1000 mA g−1, the material's reversible specific capacities remain at 234/164 mAh g−1 for PIBs/SIBs. The improved performances of the Co-HHTP/G composite electrode are due to the incorporation of graphene. This incorporation not only reduces structural stacking and promotes active site utilization, but also increases electrical conductivity and structural stability. According to the ex-situ X-ray photoelectron spectrometer (XPS) spectra, the Co-HHTP/G's energy storage mechanism throughout the process of potassisation/depotassisation is found to be linked to the aromatic rings presented in the organic ligands.

Quasi-diffusion controlled high rate sodium-ion storage performance of flame pyrolysis derived spherical hard carbon

Hard carbon (HC) is identified as a potential anode for sodium ion batteries (SIBs) due to its outstanding electrochemical performance. However, selection of synthesis routes and its precursors remain crucial to develop the HC of desired microstructures for enhanced sodium-ion storage. Herein, we employed novel flame pyrolysis route to prepare spherical HC nanoparticles (<100 nm) from a liquid precursor derived from a low-cost bio-source. The as prepared carbon has been subjected to different calcination temperatures to optimize the porosity and surface area in order to achieve maximum sodium ion storage. The HC calcined at 1200 °C has shown the optimum electrochemical performance with a high reversible capacity of ∼287 mAh/g at 0.1C (1C = 300 mA/g). It shows 72 % of capacity retention after 490 cycles when cycled at 1C, with initial reversible specific capacity of ∼235 mAh/g. Excellent rate performance has been seen even at 20 C (6 A/g) with high specific capacity of 118 mAh/g at 70 % capacity retention after 2000 cycles, which is one of the highest values reported so far. Structural and morphological characterization of HC prepared at different temperatures are carried out using X-ray powder diffraction (XRD), small angle X-ray scattering (SAXS), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. Particle size and morphology altogether have played significant role in achieving high specific capacity and C-rate performance by providing shorter diffusion path and larger sodium ion storage sites.

Preparation of nanodiamonds modified hard carbon with uniform spherical feature for improving sodium-ion storage performances

Sodium-ion batteries (SIBs) have received remarkable attention due to their abundant sodium (Na) content and low resources cost. However, the absence of high-performance anode materials make carbon-based SIBs still a challenge. Herein, nano-diamonds (NDs) modified gleditsia japonica shell carbon to form a uniform carbon microsphere, which improves the graphitization degree and Na ion adsorption, NDs also act as a strong scaffold to maintain its stability. This spherical carbon-based material exhibits superior performances including the enhanced capacity (270 mA h g−1 at 0.2C after 100 cycles) and long-cycle stability (155 mA h g−1 at 2C after 1000 cycles) when incorporated into SIBs. This work provides a green and simple synthesis strategy for fabricating high performance porous spherical carbon used for SIBs anode.

Boron-doped high-entropy oxide toward high-rate and long-cycle layered cathodes for wide-temperature sodium-ion batteries

O3-type layered metal oxides hold great promise for sodium-ion batteries cathodes owing to their energy density advantage. However, the severe irreversible phase transition and sluggish Na+ diffusion kinetics pose significant challenges to achieve high-performance layered cathodes. Herein, a boron-doped O3-type high entropy oxide Na(Fe0.2Co0.15Cu0.05Ni0.2Mn0.2Ti0.2)B0.02O2 (NFCCNMT-B0.02) is designed and the covalent B–O bonds with high entropy configuration ensure a robust layered structure. The obtained cathode NFCCNMT-B0.02 exhibits impressive cycling performance (capacity retention of 95% and 82% after 100 cycles and 300 cycles at 1 and 10 C, respectively) and outstanding rate capability (capacity of 83 mAh g−1 at 10 C). Furthermore, the NFCCNMT-B0.02 demonstrates a superior wide-temperature performance, maintaining the same capacity level (113.4 mAh g−1@−20 °C, 121 mAh g−1@25 °C, and 119 mAh g−1@60 °C) and superior cycle stability (90% capacity retention after 100 cycles at 1 C at −20 °C). The high-entropy configuration design with boron doping strategy contributes to the excellent sodium-ion storage performance. The high-entropy configuration design effectively suppresses irreversible phase transitions accompanied by small volume changes (ΔV = 0.65 Å3). B ions doping expands the Na layer distance and enlarges the P3 phase region, thereby enhancing Na+ diffusion kinetics. This work offers valuable insights into design of high-performance layered cathodes for sodium-ion batteries operating across a wide temperature.

Unraveling the functioning mechanism of fluorine-doping in Mn-based layered oxide cathodes toward enhanced sodium-ion storage performance

Manganese-based layered oxides with anionic redox activity are considered as one of the most promising cathode candidates for sodium-ion batteries (SIBs) owing to their abundant resources and high theoretical specific capacities. However, the severe Jahn-Teller (J-T) effect of Mn3+ and irreversible lattice oxygen loss result in rapid structural degradation and electrochemical performance deterioration. Herein, the functioning mechanism of F-doping in regulating the local and electronic structures of Mn-based layered oxides is unraveled. The introduction of the more electronegative F ions on one hand breaks the electronic symmetry of the MnO6 octahedra and effectively alleviates the J-T distortion, on the other hand suppresses the Zn ions migration through the strong Zn-F bonds and stabilizes the oxygen redox chemistry and facilitates the Na+ diffusion. The above reaction mechanisms are systematically validated by in-situ/ex-situ analyses and theoretical computations. As a result, the optimum P2-Na0.75Zn0.28Mn0.72O1.93F0.07 cathode demonstrates significantly improved rate capability (178.6 mAh g−1 at 0.1 C with 64.4 mAh g−1 at 10 C) and enhanced cycling durability (83.1 % capacity retention over 400 cycles at 3 C) compared to the un-doped P2-Na0.75Zn0.28Mn0.72O2 material. This study clarifies the F-doping mechanism in layered oxides and provides new perspectives for designing high-energy and high-stability cathodes for SIBs.

Comparison and optimization of biomass-derived hard carbon as anode materials for sodium-ion batteries

Hard carbon made from biomass-based precursors has many advantages as anode for sodium-ion batteries such as low cost and sustainability. In this work, three different hard carbon materials derived from bamboo, wood and coconut shell with the same particle size are screened, combining acid etching and carbonization at 1200 °C, to compare the sodium ion storage performances. The anode material originated from bamboo shows the highest specific capacity among them. Subsequently, the hard carbon from bamboo is optimized by the same process, but changing the carbonization temperature ranging from 1000 °C to 1400 °C. Among the hard carbon materials, the bamboo-derived one prepared at 1300 ℃ exhibits excellent electrochemical performances at a current density of 30 mA g−1, with a high reversible specific capacity of 303.8 mAh/g and an initial coulombic efficiency of 83.7 %. After 150 cycles, a capacity retention of 94.7 % is achieved at a current density of 300 mA g−1. This work provides a potential hard carbon anode for sodium-ion batteries to realize large-scale energy storage due to the cheap sources of bamboo.

Heterointerface-Induced Fast Na+ Transport of Sn Anode Using a Yolk-Shell Structure for Fast-Charging and Stable Sodium-Ion Batteries

Sodium-ion battery (SIB) is a promising next-generation secondary battery system that uses inexpensive sodium resources, which can lower battery production costs. Moreover, based on similar chemical and electrochemical reaction mechanisms as conventional lithium-ion battery (LIB), it is expected that technology development can be rapidly achieved by utilizing existing battery manufacturing processes. However, because of the larger ionic radius (1.02 Å) and weight of sodium compared to those of lithium (0.76 Å), SIBs inevitably have lower energy and power densities compared to LIB. Therefore, to address these challenges, developing suitable host material with superior electrochemical performance (high capacity/high power density/long cyclability) is urgently required.In this regard, metallic Sn has attracted attention as a promising anode material with a high theoretical capacity of 870 mAh/g through the reversible electrochemical (de)alloying reaction with sodium, which could overcome the low energy density limit of hard carbon anode. Nevertheless, due to the interfacial instability of Sn particles upon cycling and the slow alloying reaction rate during the sodiation process, the Sn anode exhibits poor rate performance and insufficient long-term cycling stability. Additionally, the structural degradation caused by significant volume variations further limits its practical implementation in SIBs.Here, to solve the above issues, we propose a hierarchically designed composite anode consisting of Sn yolk and multifunctional C/SiOC shell (denoted as Sn@C/SiOC) via a simple pyrolysis method using the suspension of the Sn precursor in silicone oil. We conducted various physical, chemical, and electrochemical characterization, and we further carried out an in-depth investigation including post-mortem and in-situ EIS analyses to reveal the heterointerface-induced improved sodium-ion storage performance. We expect that the heterointerface modification strategy will contribute to the realization of advanced electrode materials in SIBs and other next-generation energy storage devices.

Preparation and sodium-ion storage performance of bimetallic oxygen sulfide composite hollow carbon fibers

Preparation and sodium-ion storage performance of bimetallic oxygen sulfide composite hollow carbon fibers

Unlocking the Design Paradigm of In-Plane Heterojunction with Built-in Bifunctional Anion Vacancy for Unexpectedly Fast Sodium Storage.

Transition metal chalcogenide (TMD) electrodes in sodium-ion batteries exhibit intrinsic shortcomings such as sluggish reaction kinetics, unstable conversion thermodynamics, and substantial volumetric strain effects, which lead to electrochemical failure. This report unlocks a design paradigm of VSe2- x /C in-plane heterojunction with built-in anion vacancy, achieved through an in situ functionalization and self-limited growth approach. Theoretical and experimental investigations reveal the bifunctional role of the Se vacancy in enhancing the ion diffusion kinetics and the structural thermodynamics of Nax VSe2 active phases. Moreover, this in-plane heterostructure facilitates complete face contact between the two components and tight interfacial conductive contact between the conversion phases, resulting in enhanced reaction reversibility. The VSe2- x /C heterojunction electrode exhibits remarkable sodium-ion storage performance, retaining specific capacities of 448.7 and 424.9 mAh g-1 after 1000 cycles at current densities of 5 and 10 A g-1 , respectively. Moreover, it exhibits a high specific capacity of 353.1 mAh g-1 even under the demanding condition of 100 A g-1 , surpassing most previous achievements. The proposed strategy can be extended to other V5 S8- x and V2 O5- x -based heterojunctions, marking a conceptual breakthrough in advanced electrode design for constructing high-performance sodium-ion batteries.

Facile synthesis of MoS2/N-doped carbon as an anode for enhanced sodium-ion storage performance

Facile synthesis of MoS2/N-doped carbon as an anode for enhanced sodium-ion storage performance

Boosted sodium ion storage performance in MnO2: Understanding the bond angle-mediated orbital overlap in MnO6 units for fast charge transfer

Symmetric six oxygen-coordinated Mn structural units (MnO6) in MnO2 with small Mn–O orbital overlap hamper electron transfer rates during energy storage. Herein, we report a novel bond angle modulation strategy to manipulate Mn–O orbital overlap in MnO2 through the construction of Mn vacancies (MnO2-VMn), aiming at expediting electron transfer, and thus enhancing energy storage performance. Both experimental and theoretical results disclose that the amplification of Mn–O–Mn bond angles exclusively augments the Mn (dx2-y2)-O (py) orbital overlap and triggers the electron redistribution in MnO2-VMn, inducing an augmented Mn dx2-y2 electron occupation. This heightened presence of active electrons in the Mn dx2-y2 orbital paves the way for accelerating electron transfer and ion transfer in MnO2-VMn. Notably, MnO2-VMn delivers an improved specific capacitance of 425 F g−1 at 1 A g−1 and a superior rate capacity of 265 F g−1 at 20 A g−1. Furthermore, an asymmetric supercapacitor (MnO2-VMn//AC ASC) was fabricated, exhibiting a high energy density of 64.3 Wh kg−1 at a power density of 1000 W kg−1. Furthermore, theoretical insights uncover the profound implications of metal–oxygen–metal bond angle regulation on interatomic orbital overlap modulation. These revelations illuminate pathways for the design of advanced energy storage materials.

Hard carbon anodes for sodium-ion batteries: Dependence of the microstructure and performance on the molecular structure of lignin

Hard carbon is currently believed to be the most promising anode material for commercial sodium-ion batteries. However, the sodium-ion storage mechanism of hard carbons remains ambiguous due to the unclear relationship between their microstructures and sodium-ion storage performance. This work reports several hard carbons with different pore structures by the carbonization of different lignin precursors, and further studies the relationship between their microstructures and sodium-ion storage performance. Corn cob lignin, pine lignin, and acetylated pine lignin with different molecular structures were selected as the precursors for the preparation of hard carbons. It is found that hard carbon prepared by corn cob lignin has the highest closed pore volume, resulting in the highest plateau capacity. The formation of closed pores is due to the formation of micropores at low pyrolysis temperatures. The micropores then transform into closed pores at high carbonization temperatures. N2 adsorption/desorption, CO2 adsorption/desorption, and small-angle X-ray scattering are used to analyze the pore architectures of the obtained hard carbons, and a method for calculating the closed pore volume is proposed. It is found that the plateau capacity is positively correlated with the closed pore volume.

Designing water/air-stable Co-free high-entropy oxide cathodes with suppressed irreversible phase transition for sodium-ion batteries

Layered transitional metal oxides are promising cathode materials for sodium-ion batteries that benefit from their high energy densities. Nevertheless, the complicated irreversible phase transitions and poor air stability limit their energy efficiency and implementation in practical devices. Here, a new Co-free high-entropy oxide (HEO) layered cathode NaFe0.2Cu0.1Ni0.2Mn0.3Ti0.2O2 is proposed to enhance the reversible phase transition, improve the air stability, and further decrease the cost. The HEO cathode displays excellent sodium-ion storage performance with a capacity of 121 mAh g−1, competitive cycling stability (∼83.8% capacity retention after 200 cycles at 2 C), and enhanced water resistance (capacity of 105.2 mAh g−1 after soaking in water for 2 h and capacity retention of 83% after 200 cycles at 1 C). Moreover, the as-obtained NFCNMT‖hard carbon full cells exhibit superior performance with reversible specific capacity 115 mAh g−1 and approximately ∼73% capacity retention after 100 cycles at 1C. Ex-situ X-ray diffraction and transmission electron microscopy reveal the completely reversible O3 → P3 → O3 structure evolution and suppressed violent changes in lattice parameters owing to the high-entropy design. Furthermore, the galvanostatic intermittent titration technique and in-situ electrochemical impedance spectroscopy reveal that the HEO cathode exhibits fast Na+ diffusion kinetics. For sodium-ion batteries, this work provides a new strategy for suppressing irreversible phase transformation and enhancing air stability.

Engineering of the microstructures of enzymatic hydrolysis lignin-derived hard carbon anodes for sodium-ion batteries

Hard carbon is considered as the most commercially applicable anode for sodium-ion batteries. Lignin has the characteristics of sustainable, low cost, high carbon content (>60%) and abundant oxygen functional groups, which is expected to be used as a promising candidate precursor for low-cost hard carbons. The structure and electrochemical performances of hard carbons could be regulated by adjusting carbonization temperature. The microstructure and electrochemical performance of LDHC anode are highly dependent on the carbonization temperature. Increasing carbonization temperature could reduce specific surface area and improve initial coulombic efficiency. The slope and plateau capacity of the LDHC anode could also be adjusted by changing the carbonization temperature. The LDHC prepared at 1200 °C showed the best sodium-ion storage performance, with an initial coulombic efficiency of 78.9% and a reversible sodium-ion storage capacity of 284.7 mAh g−1.

Hydrothermal synthesis of NiSe2 octahedral structure and sodium ion storage performance

Nowadays, due to the abundant storage resources and low price of sodium, it receives extensive attention in the field of new energy batteries. NiSe2 anode material is the focus of much investigation in the search for Anode materials with promising and stable electrochemical performance and high theoretical specific capacity that have attracted much attention. Its unique nanostructure design is also an important way to improve its electrochemical properties. Therefore, the principal measure of this project is to the preparation of regular octahedral NiSe2 materials by a simple hydrothermal method. And the structure and storage mode of sodium ions is studied by relevant characterization methods. When the current density is 0.1 A g−1, the charge-specific capacity after 100 cycles is 349.8 mAh g−1, and at the current density of 2.0 A g−1, the charge-specific capacity after 500 cycles remains at 299.6 mAh g−1. It is concluded that NiSe2 nanostructure has excellent cycling stability and high specific capacity as an anode material for the sodium ions. When the current density is 0.1, 0.2, 0.5, 1, 2, 5 A g−1, the coulomb efficiency remains about 100%. When the current density is restored to 0.1 A g−1 again, the specific capacity can be restored to 370.3 mAh g−1, and it can reflect excellent ratio performance and good structural stability. The reason for these excellent electrochemical performances is ultimately related to the stable regular octahedral structure and excellent electrical conductivity of NiSe2. As a result of these investigations, suggestions are identified for future research regarding the further study of the excellent electrochemical characteristics of NiSe2 materials.

Nickel-templated carbon foam anodes for sodium-ion batteries

Sodium-ion batteries, which are abundant in resources and cost-effective, are widely considered to be suitable for large-scale energy storage. However, unstable intercalation compounds and large sodium ion radius cause carbonaceous anodes to perform poorly. Herein, a soft-and-hard composite hollow carbon foam (HCF) was one-step prepared by nickel-templated blowing strategy. The sodium-ion storage performances were enhanced by soft carbon skeleton with high conductivity, hard carbon with abundant pores, and nitrogen doping. When applied as anodes for sodium-ion storage, HCF demonstrates remarkable capacity, rate, and cycling performances. It delivers 256mAhg−1 at 0.05Ag−1 and can be cycled for 2000 times at 1Ag−1 with remaining a capacity of 139mAhg−1. Kinetic studies reveal that soft-and-hard carbon structure, nitrogen doping, and porous structure can effectively promote sodium-ion absorption, as well as the transport of electrons and ions. Therefore, sodium-ion batteries based on the carbon could facilitate the development of renewable energy sources.

Hierarchical CoSe2/TiN/nitrogen-doped carbon nanofibers wrapped with carbon nanotubes: A binder-free anode for enhanced sodium-ion storage

Transition metal chalcogenide anodes have attracted significant attention for sodium-ion batteries (SIBs) owing to their relatively high theoretical capacity. However, the inherently poor electronic conductivity and rate performance hinder their practical application. In this study, hierarchically structured CoSe2/TiN/nitrogen-doped carbon nanofibers wrapped with in-situ grown carbon nanotubes (CNTs) on the surface (denoted as CoSe2@N-TCF/CNTs) are designed and fabricated as binder-free anodes for SIBs. The rational design can effectively avoid the agglomeration of CoSe2 nanoparticles, improve the conductivity of the composite materials, provide enough space for electrolyte penetration and volume expansion during the cycling process and shorten the transmission paths of electrons and Na+. With these structural and compositional advantages, the as-obtained hierarchical CoSe2@N-TCF/CNTs deliver a high reversible capacity of 401.2 mAh g−1 after 1000 cycles at 0.2 A g−1 and maintained at 353.7 mAh g−1 even at a high current density of 2 A g−1 when directly used as a binder-free anode for SIBs. The superior sodium-ion storage performance can be attributed to the decreased charge transfer resistance, improved Na+ diffusion rate and the pseudocapacitance behavior, as is evidenced by kinetics analysis.

Understanding the origin of the improved sodium ion storage performance of the transition metal oxide@carbon nanocomposite anodes.

Transition metal oxide (TMO) anodes show inferior sodium ion storage performance compared with that of lithium ion storage owing to the larger radium size and heavier elemental mass of Na+ than Li+. Effective strategies are highly desired to improve the Na+ storage performance of TMOs for applications. In this work, using ZnFe2O4@xC nanocomposites as model materials for investigation, we found that by manipulating the particle sizes of the inner TMOs core and the features of outer carbon coating, the Na+ storage performance can be significantly improved. The ZnFe2O4@1C with a diameter of the inner ZnFe2O4 core of around 200nm coated by a thin carbon layer of around 3nm shows a specific capacity of only 120 mA h g-1. The ZnFe2O4@6.5C with a diameter of the inner ZnFe2O4 core of around 110nm embedding in a porous interconnected carbon matrix displays a significantly improved specific capacity of 420 mA h g-1 at the same specific current. Furthermore, the latter shows an excellent cycling stability of 1000 cycles with a capacity retention of 90% of the initial 220 mA h g-1 specific capacity at 1.0Ag-1. TEM, electrochemical impedance spectroscopy, and kinetic analysis show that the inner ZnFe2O4 core with reduced particle size and the outer thicker and interconnected carbon matrix synergistically improve the active reaction sites, integrity, electric conductivity, and pseudocapacitive-controlled contribution of ZnFe2O4@xC nanocomposites, thus leading to an overall enhanced Na+ storage performance. Our findings create a universal, facile, and effective method to enhance the Na+ storage performance of the TMO@C nanomaterials.

Temperature effects on hard carbon derived from sawdust as anode materials for sodium ion batteries

BackgroundElectrochemical energy storage devices, namely batteries, are vital in reducing greenhouse gas secretions and are reliable alternatives to fossil fuel-based electrical energy storage systems. Thus, hard carbon (HC) is one of the most promising sustainable materials in the energy storage sector. MethodsThis study assembled sodium ion cells using sawdust powder resource-derived HC as an anode for sodium ion storage. We studied the effects of calcination temperature for the first time. Ball-milled and acid-washed sawdust powders were prepared by calcination at different temperatures. The characterization and electrochemical analyses of the HC synthesized at different temperatures were performed. Significant findingsWe found that the ratios of C = O and the micro/meso pore size distributions in HCs corresponded highly to the sodium ion storage performance. The half-cell, HC1200 (at 1200 °C) exhibited the highest reversible capacity of 320 mAh/g after 200 cycles at 0.5 A/g. The Na3V2(PO4)3(NVP)//HC1200 pouch-type full cells showed superior capacity retention of 96.7% and a coulombic efficiency of 98.9% after 400 cycles. The as-synthesized biomass carbon derived from sawdust powder is a potential anode material for sodium ion batteries.

Yolk-shell V2O3/nitrogen-doped carbon spheres as an ultra-long life anode for half/full sodium-ion batteries

With abundant resources and multiple electron transfer, V2O3 is a potential anode material for sodium ion batteries (SIBs). However, dramatic volume changes and slow reaction kinetics during the charge/discharge process still limit its application. Herein, porous yolk-shell V2O3/nitrogen-doped carbon (V2O3/NC) spheres are produced by a simple solvothermal method combined with subsequent carbonization. In this hierarchical structure, ultra-fine nanoparticles as primary building unit facilitate ion/electron transport; unique yolk-shell structure relieves the volume strain improving the structure integrity; nitrogen-doped carbon enhances electrochemical conductivity; moreover, rational mesoporous structure accelerates electrolyte penetration and high specific surface area supplies abundant reaction sites. Based on the above merits, yolk-shell V2O3/NC spheres exhibit satisfactory sodium ion storage performance (129.5 mAh g−1 at 5.0 A g−1 after 12,000 ultra-long cycles). What's more, an assembled V2O3/NC//Na3V2(PO4)3 full cell displays outstanding cycle performance (46 mAh g−1 after 300 cycles at 0.2 A g−1), demonstrating its potential value for practical applications.