Ultrafast Sodium Storage Research Articles

Cell-Shearing Chemistry Directed Closed-Pore Regeneration in Biomass-Derived Hard Carbons for Ultrafast Sodium Storage.

The closed-pore structure of hard carbons holds the key to high plateau capacity and rapid diffusion kinetics when applied as sodium-ion battery (SIB) anodes. However, understanding and establishing the structure-electrochemistry relationship still remains a significant challenge. This work, for the first time, introduces an innovative deep eutectic solvent (DES) cell-shearing strategy to precisely tailor the cell structure of natural bamboo and consequently the closed-pore in its derived hard carbons. The DES shearing force effectively modifies the pore architecture by simultaneously shearing and dissolving amorphous components to form closed pore cores with adjustable sizes, as well as disintegrating crystalline cellulose through generation of competing hydrogen bonds to elaborately tune the pore wall thickness and ordering. The optimized closed-pore structure featuring appropriate pore size (∼2 nm) and ultra-thin (1-3 layers) disordered pore walls, exhibits abundant active sites and delivers rapid ion diffusion kinetics and high reaction reversibility. Consequently, a high reversible capacity of 422 mAh g-1 at 30 mA g-1 along with an exceptional rate capability (318.6 mAh g-1 at 6 A g-1) are achieved, outperforming almost all previous reported hard carbons. The new concept of cell-shearing chemistry for closed-pore regeneration significantly advances the applications of biomass materials for energy storage.

Controllable preparation of bismuth nanosheets as anode for ultrafast sodium storage

Controllable preparation of bismuth nanosheets as anode for ultrafast sodium storage

Controlled Synthesis of Bismuth Atomic Clusters on Porous TiO2 Nanobiscuit with Ultrafast Sodium Storage

Controlled Synthesis of Bismuth Atomic Clusters on Porous TiO₂ Nanobiscuit with Ultrafast Sodium Storage

Construction of MoS2/NiS2 heterostructure with fast interfacial reaction kinetics for ultrafast sodium storage

Constructing heterostructure is a valid method to reinforcing sodium storage performance of transition metal chalcogenides materials. Herein, a simple, safe and controllable one step hydrothermal method is proposed to synthesize MoS2/NiS2 heterostructure. Due to the difference in band gaps and work functions of MoS2 and NiS2, the charges are redistributed at the MoS2/NiS2 heterointerfaces, thereby accelerating the migration of electrons and Na+. The heterointerfaces provide extra active sites for storing Na+, thus increasing the sodium storage capacity of the heterostructure. Furthermore, the distinct redox potentials of NiS2 and MoS2 promote the structural stability of MoS2/NiS2 heterostructure during the electrochemical reaction processes. Consequently, the obtained MoS2/NiS2 heterostructure exhibits superior rate properties (339.4 mAh g−1 at 10 A g−1) and ultra-stable cycling stability (480.5 mAh g−1 after 350 cycles at 1 A g−1). This paper presents a valid strategy for creating heterostructure anodes with excellent sodium storage properties.

Edge Graphitized Oxygen-Rich Carbon Based on Stainless Steel-Assisted High-energy Ball Milling for High-Capacity and Ultrafast Sodium Storage.

Oxygen doping is an effective strategy for constructing high-performance carbon anodes in Na ion batteries; however, current oxygen-doped carbons always exhibit low doping levels and high-defect surfaces, resulting in limited capacity improvement and low initial Coulombic efficiency (ICE). Herein, a stainless steel-assisted high-energy ball milling is exploited to achieve high-level oxygen doping (19.33%) in the carbon framework. The doped oxygen atoms exist dominantly in the form of carbon-oxygen double bonds, supplying sufficient Na storage sites through an addition reaction. More importantly, it is unexpected that the random carbon layers on the surface are reconstructed into a quasi-ordered arrangement by robust mechanical force, which is low-defect and favorable for suppressing the formation of thick solid electrolyte interfaces. As such, the obtained carbon presents a large reversible capacity of 363mAhg-1 with a high ICE up to 83.1%. In addition, owing to the surface-dominated capacity contribution, an ultrafast Na storage is achieved that the capacity remains 139mAhg-1 under a large current density of 100Ag-1 . Such good Na storage performance, especially outstanding rate capability, has rarely been achieved before.

Realizing Ultrafast and Robust Sodium-Ion Storage of Iron Sulfide Enabled by Heteroatomic Doping and Regulable Interface Engineering.

Fe-based sulfides are a promising type of anode material for sodium-ion batteries (SIBs) due to their high theoretical capacities and affordability. However, these materials often suffer from issues such as capacity deterioration and poor conductivity during practical application. To address these challenges, an N-doped Fe7S8 anode with an N, S co-doped porous carbon framework (PPF-800) was synthesized using a template-assisted method. When serving as an anode for SIBs, it delivers a robust and ultrafast sodium storage performance, with a discharge capacity of 489 mAh g-1 after 500 cycles at 5 A g-1 and 371 mAh g-1 after 1000 cycles at 30 A g-1 in the ether-based electrolyte. This impressive performance is attributed to the combined influence of heteroatomic doping and adjustable interface engineering. The N, S co-doped carbon framework embedded with Fe7S8 nanoparticles effectively addresses the issues of volumetric expansion, reduces the impact of sodium polysulfides, improves intrinsic conductivity, and stimulates the dominant pseudocapacitive contribution (90.3% at 2 mV s-1). Moreover, the formation of a stable solid electrolyte interface (SEI) film by the effect of uniform pore structure in ether-based electrolyte produces a lower transfer resistance during the charge-discharge process, thereby boosting the rate performance of the electrode material. This work expands a facile strategy to optimize the electrochemical performance of other metal sulfides.

Strain engineering of Bi2Se3 anode for ultrafast sodium storage

High-performance electrodes based on the conversion or alloying mechanisms have attracted much attention owing to their high theoretical capacity, but the development of fast charging conversion or alloying type electrodes by simple methods remains a great challenge. Herein, a new type of strained bismuth selenide material (s-Bi2Se3) was obtained through post heat treatment process. Due to its unique structural advantages including large interlayer spacing and narrow band gap, ion diffusion and electron transfer accelerated significantly. Meanwhile, the lattice strain in materials is thermodynamically favorable for the redox reaction to proceed. The as prepared s-Bi2Se3 exhibits ultrafast electrochemical reaction kinetics when it is used as an anode for sodium-ion batteries (SIBs) and retained a high reversible specific capacity of 332.7 mAh/g even at the ultrahigh current density of 30 A/g after 1000 cycles. Especially, the Na-ion full cell was assembled with a cathode of Na3V2(PO4)3@C, showing excellent electrochemical performance (176.2 Wh/kg at 0.2 A/g and 99.7 Wh/kg at 1662.4 W/kg). In addition, the high-performance mechanism was explored through electrochemical tests and characterizations, which provided an important theoretical basis for the application of SIBs.

Oxygen Vacancies‐Rich TiO2/C Nanofibers with Boron, Nitrogen Dual‐Doping for Ultrafast Sodium Storage

AbstractTiO2 is an intercalation pseudocapacitive material with low potential and minor structural changes during the sodium storage process. However, the intrinsic electronic conductivity and ionic diffusion kinetics are not unsatisfactory for ultrafast sodium storage. Defect engineering plays a pivotal part in improving the sodium storage kinetics of TiO2 anode materials. Now the common defect regulation methods are complicated. Herein, a simple NaBH4 reduction method is proposed to produce rich oxygen vacancies and boron doping in nitrogen‐doped TiO2/C mesoporous nanofibers, and the finally obtained oxygen vacancies (OVs)‐rich TiO2/C nanofibers (TC‐OVs) also build internal vertical channels. This particular structure of TC‐OVs favors fast transport for electrons and ions, resulting in ultrafast rate capability (156 mAh g−1, 2 A g−1) and long lifespan (139 mAh g−1, 1000 cycles, 1.0 A g−1). The inspiring sodium storage performance of TC‐OVs benefits from the high pseudocapacitance contribution (94%, 5.0 mV s−1). This work provides a method to adjust defects and structures of TiO2 electrode materials for ultrafast chemical energy storage.

Insights into Electrochemical Processes of Hollow Octahedral Co3Se4@rGO for High-Rate Sodium Ion Storage.

Sodium ion batteries (SIBs), as an alternative and promising energy storage system, have attracted considerable attention due to the abundant reserves and low cost of sodium. However, it remains a great challenge to achieve high capacity and rate capability required for practical applications. Herein, hollow octahedral Co3Se4 particles encapsulated in reduced graphene oxide (Co3Se4@rGO) were designed and synthesized and exhibited excellent electrochemical performances as anodes of SIBs, especially rate capability. Sodiation/desodiation processes and involved mechanisms were investigated by using in situ TEM and in situ XRD. During sodiation, a crystalline Na2Se layer with numerous amorphous fine Co nanoparticles dispersed on it was observed to appear on the surface of the original Co3Se4@rGO particles, and the movable Co-Na2Se composites further migrated to the rGO network with high electron/ion dual conductivity, resulting in ultrafast sodium storage kinetics and remarkable rate performance of the Co3Se4@rGO anode evidenced by delivering a discharge capacity of 229.3 mAh g-1 at a large current density of 50 A g-1. Our findings reveal the fundamental mechanism behind the enhanced performance of the Co3Se4@rGO anode and offer valuable insights into the rational design of electrode materials for high-performance SIBs.

Boosting ultrafast and durable sodium storage of hard carbon electrode with graphite nanoribbons

Hard carbons are emerged as one of the most promising candidates for sodium storage, but suffer from poor rate performance and inferior cycling stability. Herein, we design novel hierarchically hollow hard carbon spheres by combining hydrothermal growth and catalytic graphitization. The carbon spheres have a unique tremella-like morphology assembled from ultrathin heterostructured nanosheets with interwoven graphitic ribbons/amorphous carbon textures. When employed as anode in sodium-ion batteries, the 3D hierarchical structure is able to minimize the reaction length and accelerate the ion transfer; meanwhile, the graphite nanoribbons can offer electron immigration pathways and serve as supporting framework to protect the electrode off crack. As such, the carbon electrode delivers a high capacity of 278 mAh g−1 at 0.1 A g−1, and presents no dramatic capacity loss during a long-term charge/discharge test for 1000 cycles. More importantly, the hard carbon electrode has unexpectedly ultrafast sodium storage capability. Even under a very high current density of 10 A g−1, it retains a large capacity of 146 mAh g−1, giving a retention rate of 68% against the capacity at 0.05 A g−1, which is rarely achieved for state-of-the-art hard carbon anodes.

Engineering hierarchical structure and surface of Na4MnV(PO4)3 for ultrafast sodium storage by a scalable ball milling approach

Polyanion-type Na4MnV(PO4)3 (NMVP) is attracting increasing attention as a cathode material for Na-ion batteries (NIBs) due to its high redox potential and crystal structure stability, while it is still suffering from poor intrinsic conductivity. Herein, to address such issue, a unique hierarchical bayberry-like NMVP@NC material, in which the ultra-small primary nanoparticles are embedded in N-doped carbon conductive network, is fabricated by a scalable ball milling approach. The optimum NMVP@NC electrode exhibits a high reversible capacity of 103.5 mAh g−1 at 0.5 C and maintains a desirable capacity of 82.4 mAh g−1 even at an ultrahigh rate of 100 C. After 1000 cycles at 5 C, a capacity retention ratio of 94.4% is achieved. The underlying electrochemical Na storage mechanism verified by the kinetic analysis and operando X-ray diffraction characterization reveals that the superior electrochemical performance should be attributed to the hierarchical structure with a facile ion/electron diffusion pathway and excellent interfacial compatibility. Moreover, a solid-solution and biphasic reaction mechanism for Na storage is confirmed in NMVP. Further demonstration of commercial soft carbon//NMVP@NC full cell manifests the good potential of as-prepared material for practical applications. Therefore, the NMVP@NC with rational architecture design is a considerable competitive cathode for the commercialization of NIB.

Enabling Fast Na+ Transfer Kinetics in the Whole-Voltage-Region of Hard-Carbon Anodes for Ultrahigh-Rate Sodium Storage.

Efficient electrode materials, that combine high power and high energy, are the crucial requisites of sodium-ion batteries (SIBs), which have unwrapped new possibilities in the areas of grid-scale energy storage. Hard carbons (HCs) are considered as the leading candidate anode materials for SIBs, however, the primary challenge of slow charge-transfer kinetics at the low potential region (<0.1V) remains unresolved till date, and the underlying structure-performance correlation is under debate. Herein, ultrafast sodium storage in the whole-voltage-region (0.01-2V), with the Na+ diffusion coefficient enhanced by 2 orders of magnitude (≈10-7 cm2 s-1 ) through rationally deploying the physical parameters of HCs using a ZnO-assisted bulk etching strategy is reported. It is unveiled that the Na+ adsorption energy (Ea ) and diffusion barrier (Eb ) are in a positive and negative linear relationship with the carbon p-band center, respectively, and balance of Ea and Eb is critical in enhancing the charge-storage kinetics. The charge-storage mechanism in HCs is evidenced through comprehensive in(ex) situ techniques. The as prepared HCs microspheres deliver a record high rate performance of 107 mAh g-1 @ 50 A g-1 and unprecedented electrochemical performance at extremely low temperature (426 mAh g-1 @ -40 °C).

Engineering Hierarchical Structure and Surface of Na4mnv(Po4)3 for Ultrafast Sodium Storage by a Scalable Ball Milling Approach

Engineering Hierarchical Structure and Surface of Na4mnv(Po4)3 for Ultrafast Sodium Storage by a Scalable Ball Milling Approach

A Self‐Healing Volume Variation Three‐Dimensional Continuous Bulk Porous Bismuth for Ultrafast Sodium Storage

AbstractBismuth (Bi) has attracted considerable attention as promising anode material for sodium‐ion batteries (NIBs) owing to its suitable reaction potential and high volumetric capacity density (3750 mA h cm−3). However, the large volumetric expansion during cycling causes severe structural degradation and fast capacity decay. Herein, by rational design, a self‐healing nanostructure 3D continuous bulk porous bismuth (3DPBi) is prepared via facile liquid phase reduction reaction. The 3D interconnected Bi nanoligaments provide unblocked electronic circuits and short ion diffusion path. Meanwhile, the bicontinuous nanoporous network can realize self‐healing the huge volume variation as confirmed by in situ and ex situ transmission electron microscopy observations. When used as the anode for NIBs, the 3DPBi delivers unprecedented rate capability (high capacity retention of 95.6% at an ultrahigh current density of 60 A g−1 with respect to 1 A g−1) and long‐cycle life (high capacity of 378 mA h g−1 remained after 3000 cycles at 10 A g−1). In addition, the full cell of Na3V2(PO4)3|3DPBi delivers stable cycling performance and high gravimetric energy density (116 Wh kg−1), demonstrating its potential in practical application.

MoSe2 nanosheets embedded in nitrogen/phosphorus co-doped carbon/graphene composite anodes for ultrafast sodium storage

Sodium-ion batteries have been considered a cost-effective alternative to lithium-ion batteries because of the cheap and abundant sodium reserves. However, the sluggish kinetics arising from the slow ion and electron transport, particularly at high rates, is the main bottleneck of fast sodium storage. Here, few-layer MoSe2 encapsulated by nitrogen/phosphorus (N/P) co-doped carbon and reduced graphene oxide (MoSe2@NPC/rGO) composites are fabricated through a simple polymerization reaction followed by selenization. The two-dimensional composite nanosheets effectively shorten the ion diffusion length while the few-layer MoSe2 exposes a large surface area to the electrolyte. The NPC/rGO sheets intercalated within the composites function as channels for fast electron transfer and surface reactions. First-principles calculations show quick Na transport rates on the surface of MoSe2, and quantitative kinetics analysis reveals a pseudocapacitance-dominated Na+ storage mechanism at high rates. Thanks to the ameliorating functional features and highly reversible conversion reactions, the MoSe2@NPC/rGO electrode delivers a reversible capacity of ~340 mA h g−1 after 500 cycles at 0.5 A g−1 with a high contribution by surface capacitance. It also possesses a high reversible capacity of ~100 mA h g−1 even at an extremely high current density of 50 A g−1, presenting potential application as anodes for high-power sodium-ion batteries.

Elucidating dual-defect mechanism in rhenium disulfide nanosheets with multi-dimensional ion transport channels for ultrafast sodium storage

Abstract The sodium-ion storage property in two-dimensional transition metal dichalcogenides (TMDs) is still seriously confined due to the lacking of efficient pathways for Na+ insertion, which enlightens the construction of multi-dimensional ion channels a necessary. Herein, we prepared interlayer defect, sulfur vacancy-contained ReS2 nanosheets on porous nitrogen-doped carbonized bacterial cellulose (dr-ReS2-x/NCBC). In such dual-defect configuration, the interlayer defects provide interconnected in-plane/interlamination channels for offering extra pathways of Na+ insertion/extraction and shortening ionic diffusion distance, while the sulfur vacancy could further enhance the electronic conductivity and induce more active sites for Na+ storage. Therefore, the dr-ReS2-x/NCBC anode displays an enhanced rate capacity (231.2 mAh g−1 at 5 A g−1) and a good cycling stability (187.3 mAh g−1 at 5 A g−1 after 500 cycles). Furtherly revealed by density functional theory calculations, the sodium-ion storage property is attributed to its negatively shifted binding energy for sodium ions (from −0.771 to −1.791/-1.244 eV), and alleviated structural change (from 5.8% to 3.4%/-1.6%) during sodiation/desodiation processes. The dr-ReS2-x/NCBC anode was also assembled coupling with Na3V2(PO4)3 cathode as a sodium-ion full cell for practical applications. This work is expected to offer an in-depth understanding between dual-defect engineering in TMDs-based anodes and as-enhanced sodium-storage performance.

Engineering Surface Oxygenated Functionalities on Commercial Carbon toward Ultrafast Sodium Storage in Ether-Based Electrolytes.

The pursuit of a high-capacity anode material has been urgently required for commercializing sodium-ion batteries with a high energy density and an improved working safety. In the absence of thermodynamically stable sodium intercalated compounds with graphite, constructing nanostructures with expanded interlayer distances is still the mainstream option for developing high-performance carbonaceous anodes. In this regard, a surface-functionalized and pore-forming strategy through a facile CO2 thermal etching route was rationally adopted to engineer negligible oxygenated functionalities on commercial carbon for boosting the sodium storage process. Benefitted from the abundant ionic/electronic pathways and more active reaction sites in the microporous structure with noticeable pseudocapacitive behaviors, the functionalized porous carbon could achieve a highly reversible capacity of 505 mA h g-1 at 50 mA g-1, an excellent rate performance of 181 mA h g-1 at 16,000 mA g-1, and an exceptional rate cycle stability of 176 mA h g-1 at 3200 mA g-1 over 1000 cycles. These outstanding electrochemical properties should be ascribed to a synergistic mechanism, fully utilizing the graphitic and amorphous structures for synchronous intercalations of sodium ions and solvated sodium ion compounds, respectively. Additionally, the controllable generation and evolution of a robust but thin solid electrolyte interphase film with the emergence of obvious capacitive reactions on the defective surface, favoring the rapid migration of sodium ions and solvated species, also contribute to a remarkable electrochemical performance of this porous carbon black.

Few-layer MoS2 embedded in N-doped carbon fibers with interconnected macropores for ultrafast sodium storage

Sodium-ion battery has been considered as one of the most promising next-generation rechargeable energy storage devices. However, it remains a great challenge to exploit suitable electrode materials for sodium storage owing to relatively large radius of Na+. In this study, a novel 1D fiber-like electrode material integrating few-layer MoS2, ultrathin carbon continuous framework, doped N atoms and well-defined 3D connected macropores is developed by electrospinning (denoted as MoS2/NCF-MP). When used as anode in sodium ion battery, its unique structural hierarchy is able to maximumly diminish the solid-state diffusion length, lower electrochemical resistance, accelerate Na+ transfer from bulk to electrode, and relieve the volume variation during sodiation/desodiation process, thus displays highly reversible capacity, long-term durability, along with ultrafast sodium storage capability. The stable reversible capacity of MoS2/NCF-MP reaches 480 mAh g−1 at 0.1 A g−1 after 100 cycles, and undergoes a long cycling life of 300 cycles at 1 A g−1, no visible capacity degradation is observed. More importantly, even under a very high current density of 30 A g−1, the MoS2/NCF-MP can deliver a commendable capacity of 217 mAh g−1, which means the charge/discharge step can be completed within a very short time of 26 s.

PbTe nanodots confined on ternary B2O3/BC2O/C nanosheets as electrode for efficient sodium storage

Sodium-ion batteries have become an arresting battery system for energy storage due to the rich sodium resources, while the current anode materials greatly restrict the rate and cycling properties of sodium-ion batteries. Herein, we report a novel ternary B2O3/BC2O/C nanosheets with mesoporous structure, where the ultrafine PbTe nanodots are uniformly embedded (PbTe/BC). These existing boracic phases remarkably improve the electrical conductivity of carbon matrix, even provide ample structural defects and more redox active sites to achieve highly capacitive and efficient sodium storage. The ternary nanosheets have a strong binding affinity to sodium and the boracic phases participate in the sodiation/desodiation reactions that promote the electrochemical activity for highly efficient sodium storage. The intrinsic cation vacancies of PbTe nanodots contribute extra active sites and channels to the ultrafast transport of sodium ions. The surface-controlled capacitive charge as a great contributor to sodium storage greatly favors ultrafast sodium storage. As a result, PbTe/BC anode exhibits the reversible sodium storage capacity of >1000 mAh g−1 at 0.1 A g−1, excellent rate capability of 230 mAh g−1 and high capacity retention of 90.1% after 500 cycles at 10 A g−1. These results demonstrated a new way to design boron/carbon anodes for future sodium-ion batteries.

SnS2 /Co3 S4 Hollow Nanocubes Anchored on S-Doped Graphene for Ultrafast and Stable Na-Ion Storage.

SnS2 has been widely studied as an anode material for sodium-ion batteries (SIBs) based on the high theoretical capacity and layered structure. Unfortunately, rapid capacity decay associated with volume variation during cycling limits practical application. Herein, SnS2 /Co3 S4 hollow nanocubes anchored on S-doped graphene are synthesized for the first time via coprecipitation and hydrothermal methods. When applied as the anode for SIBs, the sample delivers a distinguished charge specific capacity of 1141.8 mAh g-1 and there is no significant capacity decay (0.1 A g-1 for 50 cycles). When the rate is increased to 0.5 A g-1 , it presents 845.7 mAh g-1 after cycling 100 times. Furthermore, the composite also exhibits an ultrafast sodium storage capability where 392.9 mAh g-1 can be obtained at 10 A g-1 and the charging time is less than 3 min. The outstanding electrochemical properties can be ascribed to the enhancement of conductivity for the addition of S-doped graphene and the existence of p-n junctions in the SnS2 /Co3 S4 heterostructure. Moreover, the presence of mesopores between nanosheets can alleviate volume expansion during cycling as well as being beneficial for the migration of Na+ .