Application In Sodium-ion Batteries Research Articles

Synthesis, electrochemical and optical studies of poly(ethylene oxide) based gel-polymer electrolytes for sodium-ion secondary batteries

Sodium-ion batteries are being heavily investigated as cheaper alternatives to expensive lithium-ion batteries. However, synthesizing suitable electrolytes with sufficient ambient temperature ionic conductivities is a major bottleneck. In this work, gel-polymer electrolytes (GPEs) based on poly(ethylene oxide) (PEO) host polymer and NaClO4 ionic salt are developed by using ethylene carbonate (EC) and propylene carbonate (PC) plasticizer/solvent mixture. The optimized PEO:NaClO4:EC:PC composition (7:13:40:40 wt%) exhibits an ambient temperature ionic conductivity of 9.5 mS cm−1 and the variation of ionic conductivity with inverse temperature showed Arrhenius behavior with almost same activation energies for all the compositions. DC polarization studies on optimized composition reveals that the electrolyte is dominantly an ionic conductor (ti = 0.99) with negligible electronic conductivity (te = 0.01), which is highly desirable for an effective electrolyte. Cyclic voltammetric and linear sweep voltammetric studies confirm that the optimized composition is electrochemically stable for a voltage window of −1.85 to +1.85 V. Absence of any crystalline peaks in the X-ray diffractograms of the GPEs is a clear evidence for the amorphous nature of these GPEs. Broadening of the FTIR vibrational bands at 1000–1300 and 1700–1850 cm−1 is ascribed to the lowering of crystallinity resulting from the formation of PEO/Na+ complex through Na+ ion solvation by the polymer host. The GPE with optimized composition and highest ionic conductivity at ambient temperature is a suitable electrolyte for practical applications in sodium-ion batteries.

Constructing NiS2/NiSe2 heteroboxes with phase boundaries for Sodium-Ion batteries

Reasonable design and synthesis of anode materials with high capacity, excellent rate capability and good cycling stability is vital for the pragmatic application of sodium-ion batteries (SIBs). Transition metal chalcogenides possess immense potential on account of their distinguished redox reversibility and high theoretical specific capacity. Herein, the hollow metal sulfide/metal selenide (NiS2/NiSe2) heteroboxes with rich phase boundaries have been manufactured as anode for SIBs. The lattice distortion and charge redistribution at the phase boundary of the as-prepared NiS2/NiSe2 heteroboxes can expose more active sites, which is profitable to the adsorption of Na+ and accelerate the sodium storage kinetics process, and the unique hollow porous structure is conducive to buffering the volume expansion and can facilitate the penetration of electrolyte during the repeated Na+ de-intercalation process. By virtue of these advantages, the NiS2/NiSe2 heteroboxes delivers a good rate capability, where the average capacity at 10 A g-1 in comparison with 0.1 A g-1 is 64.3%. Otherwise, it exhibits an ultralong reversible capacity of 292 mA h g-1 after 2000 cycles at 10 A g-1 with only 0.0125% average capacity decay per cycle. The rational construction of phase boundary with unique structure in this article has guiding significance for the manufacture of progressive SIBs anode materials.

SnSe2 /FeSe2 Nanocubes Capsulated in Nitrogen-Doped Carbon Realizing Stable Sodium-Ion Storage at Ultrahigh Rate.

Metal selenides have attracted increasing attention recently as anodes for sodium-ion batteries (SIBs) because of their large capacities, high electric conductivity, as well as environmental benignity. However, the application of metal selenides is hindered by the huge volume variation, which causes electrode structure devastation and the consequent degrading cycling stability and rate capability. To overcome the aforementioned obstacles, herein, SnSe2 /FeSe2 nanocubes capsulated in nitrogen-doped carbon (SFS@NC) are fabricated via a facile co-precipitation method, followed by poly-dopamine wrapping and one-step selenization/carbonization procedure. The most remarkable feature of SFS@NC is the ultra-stability under high current density while delivering a large capacity. The synergistic effect of dual selenide components and core-shell architecture mitigates the volume effect, alleviates the agglomeration of nanoparticles, and further improves the electric conductivity. The as-prepared SFS@NC nanocubes present a high capacity of 408.1 mAh g-1 after 1200 cycles at 6 A g-1 , corresponding to an 85.3% retention, and can achieve a capacity of 345.0 mAh g-1 at an extremely high current density of 20 A g-1 . The outstanding performance of SFS@NC may provide a hint to future material structure design strategy, and promote further developments and applications of SIBs.

Covalently binding ultrafine MoS2 particles to N, S co-doped carbon renders excellent Na storage performances

MoS2 has attracted much interest for the potential application in sodium-ion batteries (SIBs) anodes because of the high theoretical capacity and electrochemical activity with Na. However, poor electrochemical performance caused by severe volume variations during the charge/discharge processes limits its practical application. Herein, we present an elaborately designed architecture comprising ultrafine MoS2 nanoparticles covalently bonded to N, S co-doped carbon (MoS2/NSC) via an in situ solid-state growth process, which displays high-capacity Na storage, fast sodiation/desodiation kinetics, and substantially mitigated volume fluctuations. As a consequence, MoS2/NSC delivers outstanding Na storage performances including a high reversible capacity of 340 mA h g−1 at 100 mA g−1 and a rate capacity of 208 mA h g−1 at 2000 mA g−1. Further assembling with a Na3V2(PO4)3/C cathode, the full-cell delivers a specific capacity of 238 mA h g−1 after 80 cycles at 50 mA g−1, demonstrating the great potential of our MoS2/NSC electrode. Density function theory calculations manifest that NSC not only presents strong binding to MoS2 but also significantly decreases the Na ion diffusion energy barrier, thus leading to robust structure stability and fast electrode kinetics. This study may open a new and efficient avenue for developing advanced MoS2 anodes for SIBs.

A "Biconcave-Alleviated" Strategy to Construct Aspergillus niger-Derived Carbon/MoS2 for Ultrastable Sodium Ion Storage.

Two-dimensional layered materials commonly face hindered electron transfer and poor structure stability, thus limiting their application in high-rate and long-term sodium ion batteries. In the current study, we adopt finite element simulation to guide the rational design of nanostructures. By calculating the von Mises stress distribution of a series of carbon materials, we find that the hollow biconcave structure could effectively alleviate the stress concentration resulting from expansion. Accordingly, we propose a biconcave-alleviated strategy based on the Aspergillus niger-derived carbon (ANDC) to construct ANDC/MoS2 with a hollow biconcave structure. The ANDC/MoS2 is endowed with an excellent long-term cyclability as an anode of sodium ion batteries, delivering a discharge capacity of 496 mAh g-1 after 1000 cycles at 1 A g-1. A capacity retention rate of 94.5% is achieved, an increase of almost seven times compared with the bare MoS2 nanosheets. Even at a high current density of 5 A g-1, a reversible discharge capacity around 400 mAh g-1 is maintained after 300 cycles. ANDC/MoS2 could also be used for efficient lithium storage. By using in situ TEM, we further reveal that the hollow biconcave structure of ANDC/MoS2 has enabled stable and fast sodiation/desodiation.

Study on the Electrochemical Features of Carbon-Coated GeS2 and GeSe2 Anodes toward Application in Sodium-Ion Battery

Study on the Electrochemical Features of Carbon-Coated GeS₂ and GeSe₂ Anodes toward Application in Sodium-Ion Battery

Synthesis of FeS-impregnated heteroatom-doped carbon nanofibers assisted by one-step vulcanization for superior sodium storage

Severe volume changes during sodiation/desodiation and the sluggish sodium reaction kinetics of FeS limit its applications in high-performance sodium-ion batteries (SIBs). To solve these problems, free-standing FeS nanocrystallites-impregnated porous N, S-doped carbon nanofibers (FeS@CNFs) is fabricated through an electrospinning technique combined with one-step vulcanization. During the vulcanization, the Fe precursor containing as-spun film is carbonized and sulfurated, and the carbon matrix is functionalized by S-containing oxygen groups meanwhile. The obtained free-standing and flexible FeS@CNFs film can be directly used as anode for SIBs without slurry-casting. The film exhibits prominent electrochemical property because low electronic conductivity and aggregation of FeS particles are resolved by introducing well-distributed FeS nanocrystallites into the conductive carbon nanofibers network. In addition, the film exhibits good structural stability with limited volume changes during cycling due to the buffer effects of CNFs. The film shows a high specific capacity of 530 mA h g−1 at 0.2 A g−1 with a high initial Coulombic efficiency of 86.2%. Additionally, with enhanced surface-dominant pseudocapacitive redox reactions, which facilitate charge transfer and ion diffusion, the FeS@CNFs delivers capacities of 367 and 278 mA h g−1 at 10 and 30 A g−1, respectively, maintaining long cycling stability with a high capacity retention rate of 87.6% after 700 cycles at 10 A g−1.

3D Carbon Networks: Design and Applications in Sodium Ion Batteries.

As the key component of a new generation for low-cost energy storage systems, sodium-ion batteries (SIBs) have attracted enormous attention and research due to its promising potentiality in large-scale electrochemical energy storage. For practical application of SIBs, carbonaceous materials have been considered to be one of the best choices for electrodes in virtue of their abundant reserves, low cost, easy availability, and environmental friendliness. 3D carbon network (3D-carbon) is of particular interests, which has displayed outstanding features, including abundant active sites, interconnected multi-level pore structures, high electronic conductivity, and excellent mechanical stability. Herein, we review the structural advantages of 3D-carbon and its preparation methods, and then discuss recent progress in 3D carbon materials and their composites for SIBs. The superior functionalities of 3D-carbon are emphasized as support templates or encapsulation shell membranes. Finally, we summarize and outline the challenges and future prospects of 3D-carbon in SIBs.

Heterogeneous Fe-Ni-P nanosheet arrays as a potential anode for sodium ion batteries

• Self-supported Fe-Ni-P nanosheet arrays are obtained as anode for PIBs. • A capacity of 201.7 mAh g −1 for Fe-Ni-P electrode at 0.5 A g −1 after 200 cycles. • The nanosheet arrays construction can s release the mechanical strain. • The volume expansion can be alleviated by the synergistic effect of Fe 2 P and Ni 2 P. Transition metal phosphates (TMPs) are considered as promising anode materials for sodium-ion batteries (SIBs) due to their high theoretical capacity (up to 1000 mAh g −1 ) and low cost. However, the poor electrochemical reaction kinetics and large volume expansion of TMPs are not conducive to practical applications in SIBs. In view of this, a kind of self-supported iron nickel phosphide (Fe-Ni-P) composite nanosheet arrays are obtained by reasonable hydrothermal reaction and phosphidation process. The nanosheet arrays construction can significantly release the mechanical strain and promote electrochemical reaction kinetics. Furthermore, the volume expansion can be largely alleviated by the synergistic effect of Fe 2 P and Ni 2 P. Benefiting from the unique design, the robust Fe-Ni-P arrays manifest remarkable Na + storage capability. The Fe-Ni-P nanosheet arrays exhibit a large discharge capacity of 300.9 mAh g −1 after 100 cycles at 0.1 A g −1 . And there is a reversible capacity of 201.7 mAh g −1 can be maintained without obvious capacity loss after 200 cycles at 0.5 A g −1 in SIBs.

A vacancy-free sodium manganese hexacyanoferrate as cathode for sodium-ion battery by high-salt-concentration preparation

Sodium manganese hexacyanoferrate (MnPBA) is attracting wide attention as an ideal low-cost cathode material for sodium-ion batteries (SIBs) because of high specific capacity, three-dimensional open framework, and low cost. However, some issues, including high [Fe(CN)6]4- vacancy concentration, a large amount of structural water in lattice, and nano-scale particles, hinder the practical application. Here, the effects of coprecipitation process under high-salt-concentration solution were systematically investigated to prepare a vacancy-free MnPBA with micro-spherical particle morphology. The sample (PBAT-80), prepared at ageing temperature of 80 °C for ageing time of 20 h, achieved high yield of 100 g L−1 (w/v = weight of production / liter of solution) and theoretical reversible capacity of 170 mAh g−1. Moreover, the relationship between crystallinity and thermal stability of MnPBAs was further investigated and the different storage mechanisms of distinct water molecules were identified. These results will be attractive for commercial applications of SIBs in large-scale energy storage systems.

Solid Solution Metal Chalcogenides for Sodium-Ion Batteries: The Recent Advances as Anodes.

The sodium-ion battery (SIB) has attracted ever growing attention as a promising alternative of the lithium-ion battery (LIB). Constructing appropriate anode materials is critical for speeding up the application of SIB. This review aims at guiding anode design from the material's perspective, and specifically focusing on solid solution metal chalcogenide anode. The sodium ion storage mechanisms of a solid solution metal chalcogenide anode is overviewed on basis of the elements it is composed of, and discusses how the solid solution character alters the electrochemical performances through diffusion and surface-controlled processes. In addition, by classifying solid solution metal chalcogenide as cation and anion, their recent applications are updated, and understanding the roles of guest elements in improving the electrochemical behaviors of a solid solution metal chalcogenide is carried out. After that, discussion of possible strategies to further optimize these anode materials in the future, flowing from crystal structure design to morphology control and finally to the intimacy improvement between conductive matrix and solid solution metal chalcogenide are also provided.

Interface and structure engineering of bimetallic selenides toward high-performance sodium-ion half/full batteries

Transition metal selenides are widely explored as promising anodes for sodium-ion batteries (SIBs) because of their high theoretical capacity. However, rapid capacity decay caused by the structural collapse during cycling greatly hampers their applications in SIBs. Herein, we report a synergistic engineering of interface and structure to synthesize CoSe2–MoSe2 yolk-shell spheres. Such exquisite boundary architecture is beneficial to improving the electrochemical kinetics. Meanwhile, the yolk-shell structure further modulates the mechanical stress for stable performance. As expected, the CoSe2–MoSe2 yolk-shell spheres deliver a high capacity of 466 mAh g−1 after 1000 cycles at the ultrahigh rate of 10 A g−1. The sodium storage mechanism of the CoSe2–MoSe2 yolk-shell spheres is investigated by kinetic tests and first-principles calculations. Coupled with a Na3V2(PO4)2O2F cathode, the as-constructed full batteries show a remarkable energy density of 133 Wh kg−1, promoting the development of high-energy density energy storage devices.

Exploration of amorphous hollow FeOOH@C nanosphere on energy storage for sodium ion batteries

Sodium ion batteries (SIBs) have enjoyed a high profile in recent years and gradually been commercialized to supplement the lithium-ion batteries system. However, the large volume expansion of anode materials within discharging and low electrical conductivity hinder the application of SIBs. In this work, a FeOOH@C composite was synthesized with the use of hydrothermal method and pyrolyzing of polydopamine. The amorphous FeOOH exhibits a hollow spherical structure to offer free space for buffering the volumetric variation. Furthermore, the outer carbon served as a protective shell could maintain the sphere integrity and enhance the electrical conductivity. Hence, benefiting from the achieved synergy of the hollow architecture, amorphous structure and carbon shell, the composite presented a long cycle life (316 mA h g−1 after 500 cycles at a current density of 100 mA g−1 and 234.5 mA h g−1 after 400 cycles at 2 A g−1) and high-rate performance (180 mA h g−1 at 5 A g−1), revealing a potential to be a promising candidate for electrode material of SIBs.

Solid-State Synthesis of Layered MoS2 Nanosheets with Graphene for Sodium-Ion Batteries

Sodium-ion batteries have potential as energy-storage devices owing to an abundant source with low cost. However, most electrode materials still suffer from poor conductivity, sluggish kinetics, and huge volume variation. It is still challenging to explore apt electrode materials for sodium-ion battery applications to avoid the pulverization of electrodes induced by reversible intercalation of large sodium ions. Herein, we report a single-step facile, scalable, low-cost, and high-yield approach to prepare a hybrid material; i.e., MoS2 with graphene (MoS2-G). Due to the space-confined effect, thin-layered MoS2 nanosheets with a loose stacking feature are anchored with the graphene sheets. The semienclosed hybrid architecture of the electrode enhances the integrity and stability during the intercalation of Na+ ions. Particularly, during galvanostatic study the assembled Na-ion cell delivered a specific capacity of 420 mAhg−1 at 50 mAg−1, and 172 mAhg−1 at current density 200 mAg−1 after 200 cycles. The MoS2-G hybrid excels in performance due to residual oxygen groups in graphene, which improves the electronic conductivity and decreases the Na+ diffusion barrier during electrochemical reaction, in comparison with a pristine one.

Ultrastable Sn-Based Anode Enabled By a Self-Nanocrystallization Strategy for Sodium-Ion Batteries

Sodium ion batteries (SIBs) are considered as an alternative of lithium-ion batteries (LIBs) in large scale energy storage due to the rich resource and low cost of sodium. However, compared with lithium ion (Li+), sodium ion (Na+) has a larger ionic radius and sluggish diffusion kinetics, hindering the further practical applications of SIBs. Hence, considerable efforts have been devoted to develop high-performance anode materials with low cost, high capacity, and long cycle life. Conversion/alloying type anodes have shown great promise for sodium ion batteries (SIBs) owing to their high theoretical capacity. However, the poor structural stability derived from the large volume expansion and short lifetime hinder their further practical applications. Herein, we report a novel anode with SnP2O7 particles homogeneously dispersed in the robust nitrogen-doped carbon matrix by a facile and scalable method. For the first time, we make use of self-nanocrystallization to generate ultrafine SnP2O7 particles, which shorten the diffusion pathway of sodium ions and electrons to promote the reaction kinetics. Ex situ transmission electron microscope (TEM) reveals that the average particle size of SnP2O7 decreases from 66 nm to 20 nm upon cycling. Furthermore, the N-doped carbon matrix forms strong interaction with the self-nanocrystallization ultrafine SnP2O7 particles, leading to a stable nanostructure without any particle aggregation under a long cycle operation. The N-doped carbon matrix and the self-nanocrystallization SnP2O7 particles together bring the SnP2O7@C anode excellent capacitive-energy-storage behavior of 82.4% at a scan rate of 0.6 mV s-1 as revealed by kinetic analysis. Benefiting from these synergistic merits, the SnP2O7@C anode shows a high reversible capacity of 403 mAh g-1 at 200 mA g-1 and outstanding cycling stability of 4000 cycles at 1000 mA g-1 (0.007 % capacity decay per cycle). This work provides new insights on the effective fabrication of high-performance conversion/alloying anode materials for SIBs. Figure 1

FeMoO4 nanorods anchored on graphene sheets as a potential anode for high performance sodium ion batteries

Metal molybdate nanostructures hold great promise as better performing electrode material for sodium ion batteries. In this work, graphene encapsulated FeMoO4 nanorods have been prepared using a simple, facile, scalable and low-cost technique. The uniform distribution of homogeneous and well-defined FeMoO4 nanorods over graphene sheets is apparently evidenced by HR-TEM. The exclusively designed architecture effectively mitigates the severe volume changes associated with the conversion mechanism driven prolonged cycling along with the improved electronic conductivity of the electrode. As a result, FeMoO4/graphene composite anode exploited for the first time as an anode for SIBs exhibits excellent electrochemical performance in terms of high specific capacity (294 mAh g−1 at 50 mA g−1 after 100 cycles), good cycling stability (83% after 100 cycles) and an acceptable rate capability (110 mAh g−1 at 1000 mA g−1). More importantly, FeMoO4/Graphene composite anode demonstrates stable cycling behavior with almost 100% capacity retention even after 1000 cycles at 0.5 A g−1, which implies that the FeMoO4/G composite anode qualifies itself as a high performing anode material for sodium ion battery applications.

Construction of flexible V3S4@CNF films as long-term stable anodes for sodium-ion batteries

The vanadium sulfides draw comprehensive attention as alternative anode materials for sodium ion batteries (SIBs) owing to their layered structural features and high theoretical capacities, but the unsatisfactory cycle life and rate performance caused by the huge volume change hinder their commercial application. Herein, we fabricate a flexible film with layered V3S4 embedded in carbon nanofiber (V3S4@CNF) via a facile and scalable industrialized electrospinning method followed by the thermal sulfuration. When evaluated as anodes for SIBs, V3S4@CNF delivers brilliant sodium storage performance (400 mAh g−1 at 0.1 A g−1; 185 mAh g−1 at 10 A g−1; capacity retention of 98% after 3500 cycles). Moreover, the assembled full cell performs remarkable capacity of 265 mAh g−1 and superior energy density of 400 Wh kg−1 at 0.1 A g−1. The carbon nanofibers-constructed film supported the integrity of the structure and constructed the cross-linked conductive skeleton to boost the electron transfer and reaction kinetic, and the layered V3S4 in the carbon nanofibers gave the mostly capacity, endowing the excellent sodium storage performance. This work not only provides a casual engineering to devise flexible freestanding electrode, but also designs a high energy density anode with great potential for practical application in SIBs.

Multi-Redox (V5+/V4+/V3+/V2+) Driven Asymmetric Sodium (De)intercalation Reactions in NASICON-Na3VIn(PO4)3 Cathode

NASICON-Na3V2−xMx(PO4)3 (M = Al3+, Cr3+, Fe3+ & Ga3+) cathodes are attractive for sodium-ion battery application due to their high voltage multi-redox (V5+/V4+/V3+) couples and faster sodium-ion diffusivity. However, they suffer from rapid capacity decay due to irreversible structural changes occurring at high voltages. Herein, we present the structural and electrochemical sodium (de)intercalation properties of NASICON-Na3VIn(PO4)3 (NVIP) cathode. Although, this In3+-substituted cathode also undergoes similar high voltage structural degradation, but its structure is rejuvenated through the following low voltage deep-sodiation process, resulting in reversible capacities of ∼145 mA h g−1 (i.e., equivalent to ∼2.82 moles of Na per vanadium). Our combined electrochemical, in-operando X-ray diffraction and exsitu X-ray absorption spectroscopy analyses reveal asymmetric sodium (de)intercalation pathways of the NVIP cathode in the window of 4.2–1.2 V vs Na+/Na0 that is driven by multi-redox (V5+/V4+/V3+/V2+) couples.

Toward a High-Energy-Density Cathode with Enhanced Temperature Adaptability for Sodium-Ion Batteries: A Case Study of Na3MnZr(PO4)3 Microspheres with Embedded Dual-Carbon Networks.

Polyanionic cathode materials that have high energy density and good temperature adaptability are in high demand for practical applications in sodium-ion batteries (SIBs). In this study, a scalable spray-drying strategy has been proposed to construct interconnected conductive networks composed of amorphous carbon and reduced graphene oxide in Na3MnZr(PO4)3 microspheres (NMZP@C-rGO). The dual-carbon conductive networks provide fast electron migration pathways in the microspheres. Moreover, they significantly increase the porosity and specific surface area of the microspheres, which are conducive to accommodating the volume change and improving the electrode/electrolyte contact interface and the contribution of the pseudocapacitance effect to achieve fast sodium storage. As a result, NMZP@C-rGO exhibits excellent rate performance (50.9 mAh g-1 at 50C and 30 °C, 35.4 mAh g-1 at 50C and -15 °C) and long-term cycling stability (capacity retentions of 97.4 and 79.6% after 1500 cycles at 30 and -15 °C, respectively) in a wide temperature range.

CoP Nanoparticles Intertwined with Graphene Nanosheets as a Superior Anode for Half/Full Sodium‐Ion Batteries

AbstractConversion‐type CoP is a promising anode candidate for sodium‐ion batteries (SIBs) thanks to their abundant resources and high theoretical capacity. However, the low reversible capacity and inferior cycle life are two major obstacles that limit its practical application in SIBs. Herein, cobalt‐based metal‐organic framework derived CoP nanoparticles coupled with reduced graphene oxide (RGO) composite (CoP/RGO) has been successfully prepared. The optimized CoP/RGO presents a high reversible capacity (258.6 mAh g−1 at 0.1 A g−1), superior rate capability (173 mAh g−1 at 2 A g−1) and extraordinary durability (155 mAh g−1 at 0.5 A g−1 after 500 cycles with the per cycle capacity decay rate of only 0.065 %). In addition, electrochemical analyses reveal fast reaction kinetics and high surface capacitive contribution in CoP/RGO composite, which can be responsible for the excellent performance. Furthermore, the CoP/RGO//Na3V2(PO4)3 sodium‐ion full cells are assembled successfully and display an initial charge capacity of 231.1 mAh g−1 at 0.1 A g−1. Considering the low cost and great electrochemical performances, this work may provide some new opportunities for the synthesis of activity anode materials for SIBs.