Fast Sodium Storage Research Articles

Highly nitrogen-doped carbon nanosheets derived from Cu-melamine coordination framework for fast lithium and sodium storage

Superior electrochemical activity with adequate electronic properties by the incorporation of nitrogen doping in carbon anode materials presents a promising prospect for the advancement of rechargeable batteries. However, the structure of two-dimensional (2D) nitrogen-rich carbon still limits the practical achievement of this concept. In order to overcome this issue, a “bottom-to-up” strategy is being presented which involved the development of highly nitrogen-doped carbon nanosheets (NDCSs) using a Cu-melamine coordination framework as a precursor. For the reinforcement of carbon framework during carbonization by utilizing the surface curing agent of hexamethylenetetramine, Cu2+ melamine coordinated with melamine molecule in order to build a 2D structure. Precise control of carbonizing temperature delivers command over lamellar thickness, crystallinity, nitrogen configuration and content (8.05–29.49 at.%). Consequently, the optimized sample brings considerable capacities of 871.1 and 258.8 mAh g−1 at 0.05 A g−1 for Li+ and Na+ storage, respectively, as well as high-rate performance (299.6 and 66.7 mAh g−1 at 10 A g−1) is achieved. This work will open a new pathway for the successful manufacturing of nitrogen-rich carbon nanosheets for energy storage applications.

Facile synthesis of hierarchical (NiCo)Se/(NiCo)Se2@C nanostructure via the synergistic effect of carbonization and selenization

Transition-metal selenides (TMSs) possess excellent redox reversibility and Se-rich TMSs have high theoretical specific capacity for sodium storage. Although carbon coating is a useful strategy to construct robust protective layer with additional high electronic conductivity, the formation of Se-poor TMSs inevitable results in low capacity. Herein, by simply adopting the synergistic strategy of carbonization and selenization, a novel kind of hierarchical (NiCo)Se/(NiCo)Se2@C nanostructure can be fabricated. The formation and redistribution of multiple phases can create porous structure and facilitate to expose maximum active sites, finally endowing (NiCo)Se/(NiCo)Se2@C multifunctional properties such as stable, large, fast and reversible sodium storage. The sodium-ion battery using this kind of electrode material exhibits a high initial specific capacity of 658.7 mA h g−1 at 1 A g−1, excellent rate capability of 324.9 mA h g−1 at 30 A g−1, superior cycle stability with a low capacity decay rate of 0.0046% per cycle for 1100 cycles at 20 A g−1. This work provides a facile strategy for designing unique hierarchical nanostructure for sodium-ion batteries.

Dual‐Interfering Chemistry for Soft‐Hard Carbon Translation toward Fast and Durable Sodium Storage

AbstractDirect pyrolysis of low‐cost and resource‐abundant pitch generally produces highly graphitized soft carbon, showing low reversible capacity and a negligible charge‐discharge plateau owing to its unsuitable microstructure for sodium storage. Herein, for the first time, an innovative dual‐interfering chemistry strategy is proposed to solve the soft‐hard carbon translation challenge. Multifunctional zinc gluconate generates dual‐mechanism interference upon decomposition and successfully regulates pitch pyrolysis: 1) the gas decomposition products (carbon oxides) may consume excess hydrogen to realize fusion‐to‐solid‐state pyrolysis of pitch, hindering microcrystalline ordering; 2) the solid compounds (i.e., organic zinc salt and ZnO nanoparticles) not only weakens strong π–π interactions between the aromatic chains of pitch but also introduces abundant closed pores into the carbon matrix. The optimized pitch‐derived hard carbon (PZHC 450–1200) shows an absorption‐insertion‐pore filling sodium storage mechanism after microstructure conversion from graphitic structure to a pore‐rich and turbostratic structure. As a result, the PZHC 450–1200 exhibits a high reversible capacity of 320 mAh g−1 at 30 mA g−1 with a more than twofold‐enhanced low‐voltage plateau capacity ratio, and outstanding rate capability that outperforms almost all previously reported pitch‐derived carbons. The concept of dual‐interfering chemistry contributes to achieving low‐cost and high‐performance hard carbon for fast and durable sodium storage.

Coupling of NiSe2 with MoSe2 confined in nitrogen-doped carbon spheres as anodes for fast and durable sodium storage

On account of the relatively high theoretical capacity and lamellar structure, MoSe2 is considered as an advanced anode material applied for sodium-ion batteries (SIBs). Unfortunately, the notorious issues of MoSe2 including low electrical conductivity, tendency to restack and aggregate and high mechanical stress during cycling usually lead to the rapid deterioration of sodium storage properties. Herein, we propose the rational design and fabrication of NiSe2 nanoparticles decorated flower-like MoSe2 nanosheets simultaneously confined in N-doped carbon spheres (denoted as MoSe2-NC/NiSe2) via successive solvothermal and selenization steps. The heterostructure as generated between NiSe2 and MoSe2 can effectively provide more rich redox chemistry and synergistic merits. Meanwhile, the derived N-doped carbon matrix can protect the MoSe2 nanosheets from agglomeration, facilitate the electron transport in the composite, and accommodate the volume variation with the help of unique porous structure. Accordingly, the hybrid composite of MoSe2-NC/NiSe2 presents a high capacity of 315 mAh g−1 at 1 A g−1 and high-rate feature with 146 mAh g−1 even over 2000 cycles at 5 A g−1, demonstrating the excellent sodium storage performance including fast charging/discharging and outstanding cycling durability when applied in SIBs.

Hierarchical wormlike engineering: Self-assembled SnS2 nanoflake arrays decorated on hexagonal FeS2@C nano-spindles enables stable and fast sodium storage

The exploitation of advanced electrode materials with an unique hierarchical architecture and physicochemical feature undertakes an extremely prominent role in achieving rapid ion-transport and remarkable performance to further promote the development of highly efficient sodium-ion batteries (SIBs). Herein, a multi-step synthesis tactic involving in-situ polymerization of dopamine, high-temperature sulfuration and subsequent solvothermal was put forward for the construction of exquisitely hierarchical wormlike architecture by growing SnS2 nanoflake arrays on hexagonal FeS2@C nano-spindles (FeS2@C@SnS2) utilizing tailor-made Fe-based metal–organic framework nanorod as an initial template. The experimental results combined with theoretical analysis thoroughly disclose that the successful construction of the hierarchical wormlike FeS2@C@SnS2 architecture can markedly afford sufficient active reaction sites and favorable Na+ adsorption, as well as accelerate ion-diffusion kinetics and enhance surface-capacitive contribution, thereby synergistically making its higher initial coulombic efficiency, more outstanding cycling capability and rate performance than FeS2@C and SnS2 samples. Specifically, the FeS2@C@SnS2 composite delivers an attractive reversible capacity up to 585.7 mAh g−1 over 1000 cycles at 1.0 A g−1, outstanding high-rate, and durable sodium storage features (only 0.07 % capacity fading each cycle over 2800 cycles at 20.0 A g−1). Moreover, ex-situ experimental characterizations systematically unravel the FeS2@C@SnS2 experiences phase transformations of preliminarily proceeding with the Na+ insertion, followed by the conversion and further alloying-dealloying reaction mechanism. Prompted by the above advantages, the FeS2@C@SnS2||Na3V2(PO4)3@C full cell presents its potential application feasibility toward SIBs, achieving good cycling performance and seductive specific capacity.

Bifunctional structure modulation of Sb-based sulfide for boosting fast and high-capacity sodium storage

A novel bimetallic sulfide CrSbS3 with both high sodium storage capacity and good rate performance is synthesized by introducing Cr atoms into the Sb2S3 structure.

Surface-driven fast sodium storage enabled by Se-doped honeycomb-like macroporous carbon.

Selenium (Se) is an ideal doping agent to modulate the structure of carbon materials to improve their sodium storage performance but has been rarely investigated. In the present study, a novel Se-doped honeycomb-like macroporous carbon (Se-HMC) is prepared by a surface crosslinking method using diphenyl diselenide as the carbon source and SiO2 nanospheres as the template. Se-HMC has a high Se weight percentage above 10%, with a large surface area of 557 m2 g-1. Owing to the well-developed porous structure in combination with Se-assisted capacitive redox reactions, Se-HMC exhibits surface-dominated Na storage behaviors, thus presenting large capacity and fast Na storage capability. To be specific, Se-HMC delivers a high reversible capacity of 335 mA h g-1 at 0.1 A g-1, and after an 800-cycle repeated charge/discharge test at 1 A g-1, the capacity is stable with no dramatic loss. Remarkably, the capacity remains 251 mA h g-1 under a very large current density of 5 A g-1 (≈20 C), demonstrating an ultrafast Na storage process. As far as we know, such a good rate performance has been rarely achieved for carbon anodes before.

Insights into sodium-ion batteries through plateau and slope regions in cyclic voltammetry by tailoring bacterial cellulose precursors

Hard carbon with high capacity with fast sodium storage is the most promising anode material for sodium-ion batteries. Many works have been made on improving the plateau and slope capacity of hard carbon in order to obtain high energy-power density sodium-ion batteries. This work explores sodium ions storage behaviors in porous carbon materials from the perspective of plateau and slope regions in cyclic voltammetry through tailoring the bacterial cellulose precursor with sulfuric acid and two-step carbonization. The influences of structure parameters including carbon layer distance, oxygen content, graphitization degree, and length and thickness of graphite crystallite help understand the strategies for improving the plateau and slope capacity. The results indicate the pre-carbonization of bacterial cellulose precursors via H2SO4 treatment introduces oxygen groups in both of bacterial cellulose matrix and bacterial cellulose derived carbon, which is beneficial for improving the slope and plateau capacity. The obtained bacterial cellulose-based carbon material with rational closed pores and micro-mesoporous structure shows a good discharging capacity of 420.6 mA h g−1 at 0.03 A g−1, and the enhanced plateau-slope capacity is 255.2 -167.1 mA h g−1 at 0.03 A g−1, respectively.

Delicate Co-Control of Shell Structure and Sulfur Vacancies in Interlayer-Expanded Tungsten Disulfide Hollow Sphere for Fast and Stable Sodium Storage.

Hollow multishelled structure (HoMS) is a promising multi-functional platform for energy storage, owing to its unique temporal-spatial ordering property and buffering function. Accurate co-control of its multiscale structures may bring fascinating properties and new opportunities, which is highly desired yet rarely achieved due to the challenging synthesis. Herein, a sequential sulfidation and etching approach is developed to achieve the delicate co-control over both molecular- and nano-/micro-scale structure of WS2- x HoMS. Typically, sextuple-shelled WS2- x HoMS with abundant sulfur vacancies and expanded-interlayer spacing is obtained from triple-shelled WO3 HoMS. By further coating with nitrogen-doped carbon, WS2- x HoMS maintains a reversible capacity of 241.7 mAh g-1 at 5 A g-1 after 1000 cycles for sodium storage, which is superior to the previously reported results. Mechanism analyses reveal that HoMS provides good electrode-electrolyte contact and plentiful sodium storage sites as well as an effective buffer of the stress/strain during cycling; sulfur vacancy and expanded interlayer of WS2- x enhance ion diffusion kinetics; carbon coating improves the electron conductivity and benefits the structural stability. This finding offers prospects for realizing practical fast-charging, high-energy, and long-cycling sodium storage.

Interfacial regulation of freestanding TiO2/C composite nanofibers for fast sodium storage

Various local contact modes were introduced by different dimensional conductive nanocarbons to regulate the TiO2/C interfaces inside the free-standing nanofibers. The two dimensional graphene decorated TiO2/C nanofibers (G-TiO2/C) achieved excellent and stable sodium storage performances, due to the construction of electronic conductive networks and plentiful TiOC channels.

Toward Extremely Fast Charging through Boosting Intercalative Redox Pseudocapacitance: A SbCrSe3 Anode for Large and Fast Sodium Storage

AbstractAlloying‐type metals with high theoretical capacity are promising anode materials for sodium ion batteries, but suffer from large volume expansion and sluggish reaction kinetics. Dispersing alloying‐type metal into a buffer matrix with interfacial anionic covalent bonding is an effective method to solve the above issues. Here, this bifunctional structural unit is designed by incorporating high‐capacity Sb metal into a rigid CrSe framework for fast‐charging applications. The high‐capacity and high‐rate sodium storage can be synergistically realized in the bifunctional SbCrSe system, where the rigid CrSe framework endows the SbCrSe3 anodes with superior structural stability and improved intercalative redox pseudocapacitance. Moreover, the volume expansion of Sb during discharge can be buffered by the CrSe chain‐like matrix. The novel SbCrSe3 anode delivers a high charge capacity of 472 mAh g−1 at a current density of 0.4 C and retains ≈100% capacity at 60 C over 10 000 cycles. Further in situ and ex situ characterization reveal the multistep reaction mechanism, and the breakage and formation of reversible SbSe bonds during (dis)charge. The proposed bifunctional structural unit that combines alloying type anodes and intercalative anodes is expected to pave a new road for the development of high capacity and high rate anode materials.

Dual anionic doping strategy towards synergistic optimization of Co9S8 for fast and durable sodium storage

Cobalt sulfides with high capacities and excellent redox activities have attracted comprehensive attention as promising anode materials for sodium-ion batteries (SIBs). However, the poor conductivity and large volume change during sodium storage render them an unprecedented challenge to rate capability and cycling stability. Herein, a dual anionic (N and Se) doping strategy is first proposed in the preparation of Co9S8 (N,Se-Co9S8) with structural and electronic optimization as anode material for SIB. It has been revealed that N doping can increase the electron density of Co9S8 at the Fermi level while Se doping could expand the lattice spacing and lower Co-S binding energy; the synergistic combination of N and Se enables Co9S8 to possess high conductivity, good Na+affinity, and effective Na+diffusion, leading to fast reaction kinetics and energetically stable performance upon charging/discharging. In consequence, the N,Se-Co9S8 delivers an exceptionally high capacity of 550 mAh g−1 at a current density of 0.1 A g−1, conspicuous rate performance of 411 mAh g−1 at 5 A g−1, and good cycling stability with a retained capacity of 406 mAh g−1 over 3000 cycles at 5 A g−1, among the best results of reported SIB anodes. The dual anionic doping strategy provides an efficient way to synergistically manipulate electrode materials for high-performance sodium ion storage.

Superimposed effect of hollow carbon polyhedron and interconnected graphene network to achieve CoTe2 anode for fast and ultralong sodium storage

Owing to the high trap density, large ionic radius, and unique crystal structure, CoTe2 shows great potential as anodes for sodium storage. However, the intrinsic poor electronic conductivity and large volume variation of CoTe2 during the charge-discharge process result in inferior electrochemical performance. Herein, three-dimensional hollow porous carbon dodecahedron composed of CoTe2 microparticles on reduced graphene oxide (rGO) nanosheets (denoted as CoTe2@3DG) is prepared by coordination regulation between rGO and Co-MOF (ZIF-67) and subsequent tellurization reaction. The CoTe2@3DG hybrids combine the synergistic advantages of the double-carbon skeleton and provide efficient volume expansion space of CoTe2 nanoparticles throughout cycling to realize excellent electrochemical capability. The electrochemical analysis and in-situ X-ray diffraction measurement reveal the fast electrons/sodium-ions transfer kinetics and phase evolution mechanism for sodium storage. Thus, the CoTe2@3DG hybrids display an excellent cycling stability (∼103 mAh g−1 is maintained after 4500 cycles at 1.0 A g−1) as well as excellent rate capability (135 mAh g−1 at 5.0 A g−1). This work proposes a simple and facile double-carbon-encapsulation technique for improving sodium storage performance in anode materials with conversion mechanisms.

MoS2 nanosheets fixed on network carbon derived from apple pomace for fast Na storage kinetics

Molybdenum disulfide (MoS 2 ), as a typical two-dimensional material with high theorical capacity (670 mAh g −1 ), is widely used for electrode material in energy storage systems. However, the inferior electronic conductivity, low stability, and sluggish kinetics make it prone to stack during cycling, resulting in a poor lifespan and rate performance. In this work, a 3D network porous structure MoS 2 /OAPC composite was fabricated by carbonizing biowaste apple pomace (AP) collected from concentrated juice factory, then oxidizing apple pomace carbon (APC), and finally sulfurizing (NH 4 ) 6 Mo 7 O 24 ∙4H 2 O/OAPC preform. The oxidization process ensures rich surface oxygen-containing functional groups on OAPC, which will provide necessary nucleation sites for the growth of MoS 2 , enhance the interfacial bonding strength and effectively avoid the agglomeration of MoS 2 sheets resulting in a stable structure and high conductivity. In addition, the 3D porous connectivity structure provides necessary guarantee for the fast kinetics of sodium transport. Therefore, the MoS 2 /OAPC anode exhibits a high capacity of 601.8 mAh g −1 after 50 cycles at a current density of 0.2 A g −1 . When the current density is as high as 2 A g −1 , a promising rate capacity of 297.2 mAh g −1 can still be maintained. • Porous network MoS 2 /OAPC was synthesized by oxidation and sulfurization of method. • Unique C-O-Mo provides stable bonding between MoS 2 and OAPC during cycling. • The OAPC network skeleton ensures a stable structure and accelerates charge transfer. • The MoS 2 /OAPC electrode exhibited fast sodium storage kinetics.

Pseudocapacitive Vanadium Nitride Quantum Dots Modified One-Dimensional Carbon Cages Enable Highly Kinetics-Compatible Sodium Ion Capacitors.

The kinetics incompatibility between battery-type anode and capacitive-type cathode for sodium ion hybrid capacitors (SIHCs) seriously hinders their overall performance output. Herein, we construct a SIHCs device by coupling with quantum grade vanadium nitride (VN) nanodots anchored in one-dimensional N/F co-doped carbon nanofiber cages hybrids (VNQDs@PCNFs-N/F) as the freestanding anode and the corresponding activated N/F co-doped carbon nanofiber cages (APCNFs-N/F) as cathode. The strong coupling of VN quantum dots with N/F co-doped 1D conductive carbon cages effectively facilitates the ion/electron transport and intercalation-conversion-deintercalation reactions, ensuring fast sodium storage to surmount aforesaid kinetics incompatibility. Additionally, density functional theory calculations cogently manifest that the abundant active sites in the VNQDs@PCNFs-N/F configuration boost the Na+ adsorption/reaction activity well which will promote both "intrinsic" and "extrinsic" pseudocapacitance and further improve anode kinetics. Consequently, the assembled SIHCs device can achieve high energy densities of 157.1 and 95.0 Wh kg-1 at power densities of 198.8 and 9100.5 W kg-1, respectively, with an ultralong cycling life over 8000 cycles. This work further verified the feasibility of kinetics-compatible electrode design strategy toward metal ion hybrid capacitors.

Construction of defective MoxW1-xS2/Cu7.2S4 polyhedral heterostructures for fast sodium storage

Molybdenum disulfide (MoS2) has great potential applications for Na+-storage mainly for its high capacity and layered graphene-like structure. However, large volume changes and poor electrochemical kinetics restrict the electrochemical performances of metal chalcogenides. Thus, defective MoxW1-xS2/Cu7.2S4 (MWS/CS) polyhedrons (DPs) composed of heterostructured MWS/CS nanosheets have been synthesized by a liquid chemical technique. The heterointerface formed between MWS and CS is mainly ascribed to its high and stable performance by stabilizing the electrochemical reaction products, promoting the electrons and Na+ ions migration and buffering the volume expansion. Eventually, MWS/CS DPs displays a high reversible capacity (566 mAh/g at 0.2 A/g) with upper initial coulombic efficiency of 96.4 %, good rate capability (459.9, 419.2 and 417.2 mAh/g at 1.0, 5.0, 10.0 A/g, separately) and excellent cycling stability (553.1 mAh/g at 5.0 A/g after 1000 cycles).

Surface-dominated ultra-stable sodium and potassium storage enabled by N/P/O tri-doped porous carbon

Sodium-ion batteries and potassium-ion batteries are attracting considerable attention for basic research and practical applications. However, the anode side is the dominative bottleneck which restricts the stability and fast charge/discharge capability of SIBs and PIBs. Heteroatom doping is considered to be an effective method to further improve the electrochemical performance of carbon materials. Herein, the N/P/O tri-doped porous carbon is obtained through an extremely simple soft chemistry route along with in-situ pyrolysis. The obtained NPO-C-800 delivers the highly reversible capacity of 301.2 and 213.5 mA h g−1 after 100 and 2000 cycles at 0.1 and 1.0 A/g in sodium-ion batteries. It is worth mentioning that the high specific capacity could still be retained with negligible capacity decay after 12,000 cycles at 10 A/g, which should be ascribed to the surface-dominated storage mechanism. Additionally, NPO-C-800 presents a highly reversible specific capacity of 269.4 mA h g−1 at 0.1 A/g after 100 cycles and excellent cycling stability at 1.0 A/g in potassium-ion batteries. The fast and stable surface-dominated pseudocapacitive sodium and potassium storage enabled by heteroatom doping represents a promising strategy to boost the performance of carbon anodes towards high‐power rechargeable batteries.

Microporous Carbon Nanospheres with Fast Sodium Storage Capability Enabled by Dominant Capacitive Behavior.

Hard carbon is considered one of the most promising anode candidates for sodium ion batteries but suffers from a moderate rate performance. Here, we design microporous carbon nanospheres using a novel hybrid monomer that simultaneously involves an organic moiety and an inorganic moiety as the starting unit. The inorganic moiety forms a continuous network, which serves as a 3D scaffold and a nanometer-scale template, then supports the off-collapse of the carbon skeleton and creates a well-developed microporous structure. In addition, the graphite microcrystal structure can be tailored by adjusting the heating treatment temperatures. The electrochemical study demonstrates that the microporous carbon nanospheres show dominant capacitive sodium storage behavior, thus presenting an outstanding rate performance. Even if a very high current density of 10 A g-1 is applied, the hard carbon anode can deliver a large capacity of 127 mAh g-1 with a considerable plateau capacity of 53 mAh g-1, which has rarely been obtained in previous publications. Besides, the carbon anode has a good cycling stability, and the capacity reached 210 mAh g-1 after 1000 cycles with a current density of 1 A g-1, showing no dramatic capacity loss.

Two‐in‐one shell configuration for bimetal selenides toward fast sodium storage within broadened voltage windows

AbstractThe shell structure design has been recognized as a highly efficient strategy to buffer the severe volume expansion and consecutive pulverization of conversion‐type anodes. Nevertheless, construction of a functional shell with a stabilized structure that meets the demands of both high electronic conductivity and feasible pathways for Na+ ions has been a challenge so far. Herein, we design a two‐in‐one shell configuration for bimetal selenides to achieve fast sodium storage within broadened voltage windows. The hybridized shell, which benefits from the combination of titanium dioxide quantum dots and amorphous carbon, can not only effectively buffer the strain and maintain structural integrity but also allow facile and reversible transport of electrons and Na+ uptake for electrode materials during sodiation/desodiation processes, resulting in increased reaction kinetics and diffusion of sodium ions, conferring many benefits to the functionality of conversion‐type electrode materials. As a representative material, Ni‐CoSe2 with such structural engineering shows a reversible capacity of 515 mAh g−1 at 0.1 A g−1 and a stable capacity of 416 mAh g−1 even at 6.4 A g−1; more than 80% of the capacity at 0.1 A g−1 could be preserved, so that this strategy holds great promise for designing fast‐charging conversion‐type anodes in the future.

Ordered Macroporous MoS2‐Carbon Composite with Fast and Robust Sodium Storage Properties to Solve the Issue of Kinetics Mismatch of Sodium‐Ion Capacitors

Metal‐ion capacitors (including Li+, Na+, and K+) effectively combine a battery negative electrode capable of reversibly intercalating metal cations, together with an electrical double‐layer positive electrode. However, such novel cell design has a birth defect, namely kinetics mismatch between sluggish negative electrode and fast positive electrode, thus limiting the energy‐power performance. Herein, we design a MoS2‐carbon composite anode with the ordered macroporous architecture and interlayer‐expanded feature, exhibiting the fast and reversible Na+ redox processes. This kinetically favored anode is coupled with a homemade activated carbon cathode that allows for the excellent electrochemical performance of sodium‐ion capacitor with respect to large specific capacity, high‐rate capability, and robust cycling. Through quantification of the potential swings of anode and cathode via a three‐electrode Swagelok cell, we for the first time observe the abnormal variation law of potential swings and thus directly providing the evidence that the kinetics gap has been filled up by this kinetically favored anode. Our results represent a crucial step toward understanding the key issues of kinetics mismatch for hybrid cell, thus propelling the development of design of kinetically favored anode materials for high‐performance metal‐ion capacitors.