Sodium Storage Capacity Research Articles

In Situ, Atomic-Resolution Observation of Lithiation and Sodiation of WS2 Nanoflakes: Implications for Lithium-Ion and Sodium-Ion Batteries.

WS2 nanoflakes have great potential as electrode materials of lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) because of their unique 2D structure, which facilitates the reversible intercalation and extraction of alkali metal ions. However, a fundamental understanding of the electrochemical lithiation/sodiation dynamics of WS2 nanoflakes especially at the nanoscale level, remains elusive. Here, by combining battery electrochemical measurements, density functional theory calculations, and in situ transmission electron microscopy, the electrochemical-reaction kinetics and mechanism for both lithiation and sodiation of WS2 nanoflakes are investigated at the atomic scale. It is found that compared to LIBs, SIBs exhibit a higher reversible sodium (Na) storage capacity and superior cyclability. For sodiation, the volume change due to ion intercalation is smaller than that in lithiation. Also, sodiated WS2 maintains its layered structure after the intercalation process, and the reduced metal nanoparticles after conversion in sodiation are well-dispersed and aligned forming a pattern similar to the layered structure. Overall, this work shows a direct interconnection between the reaction dynamics of lithiated/sodiated WS2 nanoflakes and their electrochemical performance, which sheds light on the rational optimization and development of advanced WS2 -based electrodes.

Zn-Ce based bimetallic organic frameworks derived ZnSe/CeO2 nanoparticles encapsulated by reduced graphene oxide for enhanced sodium-ion and lithium-ion storage

Metal-organic frameworks (MOFs) are used to derive inorganic material, which is an effective way to achieve high performance electrode materials for sodium-ion batteries (SIBs) and lithium ion batteries (LIBs). In this work, a novel orthorhombic bimetallic organic framework, [ZnCe(L7)·2H2O]n (termed as ZnCeL, L = 5-aminoisophthalic acid) with 3D open framework was synthesized via a simple solvothermal reaction. Then ZnSe/CeO2/RGO was successfully fabricated via pyrolysis and selenization of ZnCeL and graphene oxide (RGO) composites. In the hybrid, ZnSe with high theoretical specific capacity and CeO2 with electrocatalytic property are wrapped by conductive RGO. Herein, ZnSe/CeO2/RGO displays excellent sodium and lithium-storage performances. It reveals a sodium storage capacity of 113.2 mAh g−1 after 2000 cycles at 2.0 A g−1. Meanwhile, ZnSe/CeO2/RGO as an anode for LIBs delivers a reversible capacity of 675 mAh g−1 at 0.1 A g−1 after 200 cycles. The electrochemical kinetic analysis reveals that the redox reactions are dominated by pseudocapacitive behavior. The excellent performance reveals a bright prospect of the bimetallic organic frameworks derived inorganic material for energy storage.

Layered P3-Type K0.4Fe0.1Mn0.8Ti0.1O2 as a Low-Cost and Zero-Strain Electrode Material for both Potassium and Sodium Storage.

Layered transition metal oxides are ideal Na+/K+ host materials due to their high theoretical capacities and appropriate working potentials, and the pursuit of cost-effective and environmentally friendly alternatives with high energy density and structural stability has remained a hot topic. Herein, we design and synthesize a low-cost and zero-strain cathode material, P3-type K0.4Fe0.1Mn0.8Ti0.1O2, which demonstrates superior properties for both potassium and sodium storage. The cathode delivers a reversible potassium storage capacity of 117 mA h g-1 at 20 mA g-1 and a fast rate capability of 71 mA h g-1 at 1000 mA g-1. In situ X-ray diffraction reveals a solid-solution transition with a negligible volume change of 0.5% upon K+ insertion/deinsertion that ensures long cycling stability over 300 cycles. When the material is employed for sodium storage, a spontaneous ion-exchange process with Na+-containing electrolytes occurs. Thanks to the positive effects of the remaining K+ ions that protect the layered structure from collapse as well as expand the interlayer structure, and the resulting K0.12Na0.28Fe0.1Mn0.8Ti0.1O2 demonstrates a high sodium storage capacity of 160 mA h g-1 and superior cycling stability with capacity retention of 81% after 300 cycles as well as fast kinetics.

Hollow ZIF-67-C/LDO core/shell heterostructure as a high-performance anode material for sodium ion batteries

The rapid development of novel renewable energy storage systems promotes the evolution of sodium ion batteries. Among various anode materials, the conversion-type material with high sodium storage capacity suffers from large irreversible volume change during charge–discharge, which eventually results in inferior cycling performance. Herein, heterostructure hollow ZIF-67-C/layered double oxides (LDO) nanoparticles as an anode material are constructed to realize high sodium storage performance. The hollow ZIF-67-C/LDO anode with high electrical conductivity and specific surface area endows electrodes with fast electron/ion transport and reduced voltage hysteresis. As a consequence, the ZIF-67-C/LDO with calcination under 350 °C possesses a high sodium storage capacity of 341 mAh g−1 at 0.1 A g−1 and superior rate performance with a capacity of around 200 mAh g−1 at 2 A g−1. The hollow core/shell structure can not only improve the specific surface area but also alleviate the stress during the electrochemical reactions, leading to enhanced capacity and improved structural stability of the electrode material.

Directional Oxygen Functionalization by Defect in Different Metamorphic‐Grade Coal‐Derived Carbon Materials for Sodium Storage

As the limiting factor for an energy storage technique from lab‐scale to industrial‐scale, cost means not only the price of raw materials but also the simplicity of processing technics. In this work, the oxygen functionalized carbon materials were obtained from three representative different metamorphic‐grade coals, that is, lignite, bitumite, anthracite. Oxygen functional groups like quinones, carboxylic anhydrides, and lactones are easier to form near defects according to the thermogravimetric‐mass spectrometry measurements and density functional theory calculation. Considering the highest amount of defects and C=O contained functional groups, the low metamorphic‐grade lignite derived carbon exhibits a reversible capacity of 259.7 mA h g−1 after 50 cycles at 0.03 A g−1, best among these micron sized coal‐based carbons. The surface active sites contribute highly stable and majority of sodium storage capacity evidenced by in situ Raman spectra and cyclic voltammetry curves at different scan rates. The coal‐based carbon materials in this work offer options for industrial applications of sodium‐ion battery anode materials.

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.

Towards stable and high‐capacity anode materials for sodium‐ion batteries by embedding of Sb/Sn nanoparticles into electrospun mesoporous carbon fibers

AbstractAntimony and tin are promising anode materials for sodium‐ion batteries due to their high theoretical sodium storage capacities. However, significant volume change during cycling limits their long‐term stability and rate performance. Composite engineering can minimize this problem. A versatile method for the synthesis of Sb nanoparticles inside the mesopores of carbon fibers prepared through electrospinning and subsequent carbothermal reduction is presented in this work. The mesopore architecture can host up to 61 wt% of Sb nanoparticles and buffer the volume changes during cycling. Smaller pores in the carbon provide the pathways for reversible insertion/extraction of sodium. This binder‐free material provides high rate capability and a long‐term cycling performance when used as an anode in half‐cells. When cycled at 0.5 A g−1, the composite shows an initial capacity of 520 mA h g−1 with 507 mA h g−1 remaining after 500 cycles. Even at a high current density of 20 A g−1, a capacity of 197 mA h g−1 is still achieved. Sn nanoparticles can be embedded in the mesopores of the carbon fibers by a similar method. These Sn‐based anodes also show remarkable electrochemical performance, indicating that this approach represents a generally applicable strategy for synthesizing advanced battery anodes.

Approaching the Theoretical Sodium Storage Capacity and Ultrahigh Rate of Layer‐Expanded MoS2 by Interfacial Engineering on N‐Doped Graphene

AbstractMolybdenum disulfide (MoS2) holds great potential for sodium storage due to its high theoretical capacity of 670 mAh g−1. However, its theoretical capacity is hardly realized because of low conductivity, sluggish electrochemical kinetics, and unsatisfied structural stability. Herein, a polyaniline‐mediated interfacial engineering strategy for the growth of interlayer‐expanded MoS2 nanoflowers on N‐doped graphene “land” (E‐MoS2/NG) using Mo7O246− anions adsorbed on positively charged polyaniline as the “seeds” is reported. The strong interfacial interaction between MoS2 and graphene through MoN bonds as well as ultrathin interlayer‐expanded MoS2 can significantly improve the electrochemical kinetics and structural stability. As a result, E‐MoS2/NG with a high MoS2 content of 90 wt% shows a high capacity (620 mAh g−1 at 0.1 A g−1), an ultrahigh rate capability (201 mAh g−1 at 50 A g−1), and outstanding cycle performance (390 mAh g−1 after 1000 cycles at 1 A g−1). Importantly, MoS2 in the composite approaches its theoretical capacity of 670 mAh g−1. Furthermore, the assembled E‐MoS2/NG//activated carbon sodium ion capacitor delivers high energy densities of 150 and 82 Wh kg−1 at 35 and 14 421 W kg−1, respectively, and a capacity retention of 78.1% after 1500 cycles at 10 A g−1, demonstrating great potential for practical application.

In-situ plantation of Fe3O4@C nanoparticles on reduced graphene oxide nanosheet as high-performance anode for lithium/sodium-ion batteries

Fe3O4 is considered to be an ideal substitute for graphite anode due to its high lithium (Li) and sodium (Na) storage capacity, however, its sharp volume change after lithiation/sodiumization and poor electrical conductivity have brought huge challenges to the practical application. In this study, a lamellar Fe3O4-based electrode was constructed via an in-situ plantation of carbon-coated Fe3O4 nanoparticles on the surface of the reduced graphene oxide nanosheet. Owing to the ultra-small carbon-coated Fe3O4 nanoparticles (~12.5 nm) and unique two-dimensional lamellar structure, the obtained sample displays excellent cycle and rate performance in lithium/sodium-ion batteries. A high reversible capacity of 849 mA h g−1 is obtained at 500 mA g−1 after 120 cycles for lithium-ion batteries and a discharge capacity up to 429 mA h g−1 is remained at 100 mA g−1 after 300 cycles for sodium-ion batteries.

Distinct osmoregulatory responses to sodium loading in patients with altered glycosaminoglycan structure: a randomized cross-over trial

BackgroundBy binding to negatively charged polysaccharides called glycosaminoglycans, sodium can be stored in the body—particularly in the skin—without concurrent water retention. Concordantly, individuals with changed glycosaminoglycan structure (e.g. type 1 diabetes (DM1) and hereditary multiple exostosis (HME) patients) may have altered sodium and water homeostasis.MethodsWe investigated responses to acute (30-min infusion) and chronic (1-week diet) sodium loading in 8 DM1 patients and 7 HME patients in comparison to 12 healthy controls. Blood samples, urine samples, and skin biopsies were taken to investigate glycosaminoglycan sulfation patterns and both systemic and cellular osmoregulatory responses.ResultsHypertonic sodium infusion increased plasma sodium in all groups, but more in DM1 patients than in controls. High sodium diet increased expression of nuclear factor of activated t-cells 5 (NFAT5)—a transcription factor responsive to changes in osmolarity—and moderately sulfated heparan sulfate in skin of healthy controls. In HME patients, skin dermatan sulfate, rather than heparan sulfate, increased in response to high sodium diet, while in DM1 patients, no changes were observed.ConclusionDM1 and HME patients show distinct osmoregulatory responses to sodium loading when comparing to controls with indications for reduced sodium storage capacity in DM1 patients, suggesting that intact glycosaminoglycan biosynthesis is important in sodium and water homeostasis.Trial registration These trials were registered with the Netherlands trial register with registration numbers: NTR4095 (https://www.trialregister.nl/trial/3933 at 2013-07-29) and NTR4788 (https://www.trialregister.nl/trial/4645 at 2014-09-12).

Sulfur and nitrogen dual-doped carbon nanofiber with enlarged interlayer distance as a superior anode material for sodium-ion capacitors

Sodium-ion capacitors (SICs) have attracted widespread attention due to their combination of high-energy batteries and high-power supercapacitors as well as low cost of sodium resources. However, the anodes exhibit low specific capacities and sluggish kinetics, thus limiting fast development of high-performance SICs. In the present work, the sulfur and nitrogen dual-doped carbon nanofiber (S-NCNF) membrane was synthesized as a novel anode material of SICs. Introduction of S atoms can result in an enlarged interlayer distance of 0.38 nm in S-NCNF, which is beneficial to Na+ ion insertion and the electron transport. As a result, the obtained S-NCNF electrode shows high sodium-storage capacity (298 mAh g−1 at 0.1 A g−1) and superior rate capability (188 mAh g−1 at 5 A g−1). The fabricated SIC delivers high energy density (97 Wh kg−1) and power density (17 kW kg−1) as well as long cycle life (3000 cycles).

Functionalized M2TiC2Tx MXenes (M = Cr and Mo; T = F, O, and OH) as high performance electrode materials for sodium ion batteries.

First-principles calculations were performed to study the electrochemical performance of M2TiC2 (M = Cr or Mo) and M2TiC2Tx (T = O, F or OH) used as anode materials for sodium ion batteries (SIBs). The O functionalized MXenes (Cr2TiC2O2 and Mo2TiC2O2) are found to be more stable than F and OH terminated systems. The diffusion performance of sodium in MXene materials is mainly affected by the functional groups. The lowest diffusion barrier of functionalized MXenes is about one order larger in magnitude than that of bare MXenes. Although the introduction of O-groups hinders the diffusion of sodium, it can greatly improve the theoretical storage capacities. Meanwhile, the diffusion paths and diffusion energy barriers of Na are affected by Na concentration effects, while the interactions between terminations have little effect. Furthermore, multiple layers of sodium atoms are found to be adsorbed between the layers of M2TiC2O2, thus significantly increasing the theoretical capacities. The theoretical sodium storage capacities of M2TiC2O2 monolayers reach 515.70 mA h g-1 (M = Cr) and 362.46 mA h g-1 (M = Mo) and the OCVs can approach 0.034 V (M = Cr) and 0.042 V (M = Mo). Therefore, Cr2TiC2O2 and Mo2TiC2O2 are expected to be promising anode materials for SIBs due to their excellent properties, such as good electronic conductivity, low sodium diffusion barrier, and high theoretical sodium storage capacity.

Revealing the sodium‐storage performance enhancement of adsorption‐type carbon materials after ammonia treatment: Active nitrogen dopants or specific surface area?

Adsorption-type carbon materials are promising candidates for fast sodium-ion storage via surface physisorption or chemisorption of sodium ions. Post-treatment of carbon such as ammonia can simultaneously strengthen both adsorption effects by increasing the specific surface area for physisorption, and by introducing active nitrogen dopants for chemisorption. Which factor, however, the increment of specific surface area or the introduction of active nitrogen dopants, predominantly contributes to sodium-storage capacity increment, remains a question. Answering this question is of great importance for understanding the sodium storage mechanism of adsorption-type carbon materials and thereby optimizing their sodium storage capabilities. In this work, pristine carbon is thermally treated in ammonia at temperatures from 600 to 1200°C, resulting in a simultaneous increase of specific surface area (8.6-1155 m2 g−1) and active nitrogen dopants (0.75-6.47 wt%). Correlations between sodium storage capacity and specific surface area/active nitrogen dopants are established. It is found that as the post-treatment temperature increases, the capacity increment is contributed first by sodium physisorption on active surface, and then by sodium chemisorption on nitrogen dopants. Our findings enrich the mechanistic understanding of sodium storage in adsorption-type carbon materials, which may guide the rational designs of carbon materials for high-rate sodium-based energy storage systems.

Highly Purified Carbon Derived from Deashed Anthracite for Sodium-Ion Storage with Enhanced Capacity and Rate Performance

Anthracite-derived carbon is regarded as a promising anode material for sodium-ion batteries due to the advantages of high cost effectiveness and considerable sodium storage capacity. However, orig...

(Invited) Design Hybrid Nanocomposites As Electrode Materials for High Performance Na-Ion Batteries

Sodium-ion batteries are of major importance, especially for large-scale energy storage devices, due to low cost and abundant source of sodium. As for the anode side, commercial graphite shows a limited capacity for sodium storage. Compared to graphite based intercalation, the electrode materials based on conversion and alloy have been identified as promising anode candidates for sodium storage due to high theoretical capacity. However, poor kinetics and large volume change result in a low reversible capacity and fast capacity decay.In order to address the above problems, we have designed a series of carbon-based hybrid materials with hierarchical structures, such as carbon nanowire-encapsulated selenides, carbon nanosheet-supported sulfides, and mesoporous carbon-encapsulated phosphorus. These multi-scale and hierarchically organized structures construct a highly efficient and stable mixed conductive network around the nano-active components. At the same time, they can keep the electrode integrity on cycling. These lead to excellent electrochemical performance.

Copper and carbon-incorporated yolk-shelled FeP spheres with enhanced sodium storage properties

By virtue of high theoretical sodium storage capacities and low cost, FeP is a prospective anode material for sodium-ion batteries (SIBs). Nevertheless, poor cycling and rate performance greatly limit the application of FeP in practice. Herein, a facile template-engaged method is employed to synthesize copper and carbon-incorporated yolk-shelled FeP (denoted as YS-Cu-FeP@C) spheres. The copper is doped into FeP, while the carbon layer with N-doping is coated on the surface of yolk-shelled FeP spheres. Aided by the unique compositional and structural advantages, the as-synthesized YS-Cu-FeP@C spheres exhibit enhanced electrochemical performance for SIBs, including excellent rate capability (145 mAh g −1 at 10 A g −1 ) and remarkable long-term cycle performance (up to 900 cycles at 1 A g −1 ). This work provides a rational design and synthetic strategy to boost the sodium storage properties of metal phosphide-based electrode materials. • A template method is developed to synthesize copper and carbon-incorporated yolk-shelled FeP spheres. • The copper is doped into FeP, while the carbon layer with N-doping is coated on the surface. • Excellent rate capability (145 mAh g−1 at 10 A g−1) and remarkable long-term cycle performance is demonstrated.

Nanoframes@CNT Beads-on-a-String Structures: Toward an Advanced High-Stable Sodium-Ion Full Battery.

Engineering intriguing electrode with exceptional kinetics behaviors is imperative for boosting sodium storage systems. Herein, the uniform nanoframes are threaded by the interwoven carbon nanotube (CNT) conductive network to form an ingenious beads-on-a-string structured NiFePBA nanoframe/CNT (NFPB-NF/CNT) cathode and the corresponding derivative NiFeSe nanoframe/CNT (NFS-NF/CNT) anode. NFPB-NF/CNT exhibited remarkable cycling life along with outstanding rate capability and low voltage decay per cycle. The fast Na+ conduction and sufficient sodiation reaction is proved using Na+ diffusion models. Meanwhile, an exceptional sodium storage capacity and prolonged cycling life is achieved using binary NFS-NF/CNT anode at a high rate. In situ and ex situ investigations are used to reveal the sodium storage mechanisms and structural evolution process. Furthermore, a sodium-ion full battery based on the above electrodes shows stable performance accompanied by high energy conversion efficiency. The material design strategy provides a new solution for exploiting smart multicomponent composites toward advanced energy storage devices.

MoS2 self-embedded in pleated carbon pyrolyzed by ionic liquids as a high-performance anode materials for lithium-/sodium-ion batteries

MoS2 is a promising anode with high theoretical capacity in lithium-/sodium-ion batteries. Nevertheless, the unstable structure and poor conductivity of MoS2 limit its practical applications. Herein, a carbon layer-coated MoS2 composite (MoS2/C) is synthesized by a pyrolysis strategy, in which ionic liquid-derived carbon improves the conductivity and structural stability of composites by wrapping MoS2. When MoS2/C composite is used as anode in lithium-/sodium-ion batteries, it exhibits excellent stability, high capacity and long cycle life. After 50 cycles at 100 mA g−1, the lithium storage capacity of the MoS2/C composite is more than 760 mAh g−1, and the sodium storage capacity reaches 480 mAh g−1. When the current density is 2 A g−1, the sodium storage capacity maintains at 355 mAh g−1 after 500 cycles. Even after 1000 cycles, it still exhibits a stable lithium storage capacity of 350 mAh g−1 at the current density of 4 A g−1. The improved performance of MoS2/C composite can be explained by its stable structure and high charge mobility.

Walnut-like MoO2 with interconnected skeleton and opened muti-channel for fast sodium storage

Molybdenum dioxide (MoO2) has attracted lots of theoretical interest as an anode material for sodium ion batteries (SIBs) due to its high theoretical capacity (836 mA h g−1) and metallic electrical conductivity (1.9 × 102 S cm−1). The insertion reaction, forming Na0.98MoO2 and the reversible conversion reaction, forming Mo and Na2O from Na0.98MoO2 contribute capacities of 209 and 627 mA h g−1, respectively, the latter occupies 75% of the totally theoretical capacity. However, intrinsic slow kinetics in bulk MoO2 severely restricts the redox conversion reaction. In the present work, a walnut-like MoO2 architecture (W-MoO2) with opened multi-channel and interconnected skeleton was prepared in a tube furnace, providing an interconnected ion/electron dual-pathway, which effectively facilitates Na+ diffusion and reduces the internal resistance of the cells. The W-MoO2 anode demonstrates an enhanced reversible sodium storage capacity of 354.7 mA h g−1 at 0.5 A g−1.

Synthesis of phase-pure Cd2GeO4/G nanorods for high capacity Na-ion battery anode

Cd2GeO4 (CdGO) nanorods encapsulated with graphene is investigated as a potential anode for the first time in sodium ion batteries. Cd2GeO4 (CdGO) nanorods have been successfully synthesized by hydrothermal method and well dispersed on graphene to obtain Cd2GeO4/G (CdGO/G) composite. The encapsulation of Cd2GeO4 (CdGO) nanorods by graphene is clearly evidenced from HR-TEM analysis. The introduction of graphene as a compositing additive, results in an advanced performance with a reversible sodium storage capacity exceeding 162 mAh g−1. In addition, such a carbon wrapping on Cd2GeO4 (CdGO) nanorods enables further improvement in terms of capacity retention and high rate capability (up to 3.2 A g−1). Moreover, the newly prepared mixed metal oxide nano rods, viz. Cd2GeO4 (CdGO) leaves ample scope to investigate wide variety of series of germanates as probable SIB anode, for which the currently adopted simple synthesis protocol could be followed.