Anode For Sodium-ion Batteries Research Articles

Turning plastics/microplastics into valuable resources? Current and potential research for future applications

Plastics are a wide range of synthetic or semi-synthetic materials, mainly consisting of polymers. The use of plastics has increased to over 300 million metric tonnes in recent years, and by 2050, it is expected to grow to 800 million. Presently, a mere 10% of plastic waste is recycled, with approximately 75% ended up in landfills. Inappropriate disposal of plastic waste into the environment poses a threat to human lives and marine species. Therefore, this review article highlights potential routes for converting plastic/microplastic waste into valuable resources to promote a greener and more sustainable environment. The literature review revealed that plastics/microplastics (P/MP) could be recycled or upcycled into various products or materials via several innovative processes. For example, P/MP are recycled and utilized as anodes in lithium-ion (Li-ion) and sodium-ion (Na-ion) batteries. The anode in Na-ion batteries comprising PP carbon powder exhibits a high reversible capacity of ∼340 mAh/g at 0.01 A/g current state. In contrast, integrating Fe3O4 and PE into a Li-ion battery yielded an excellent capacity of 1123 mAh/g at 0.5 A/g current state. Additionally, recycled Nylon displayed high physical and mechanical properties necessary for excellent application as 3D printing material. Induction heating is considered a revolutionary pyrolysis technique with improved yield, efficiency, and lower energy utilization. Overall, P/MPs are highlighted as abundant resources for the sustainable production of valuable products and materials such as batteries, nanomaterials, graphene, and membranes for future applications.

Unlocking the Potential of Iron Sulfides for Sodium-Ion Batteries by Ultrafine Pulverization.

Iron sulfides have attracted tremendous research interest for the anode of sodium-ion batteries due to their high capacity and abundant resource. However, the intrinsic pulverization and aggregation of iron sulfide electrodes induced by the conversion reaction during cycling are considered destructive and undesirable, which often impedes their capacity, rate capability, and long-term cycling stability. Herein, an interesting pulverization phenomenon of ultrathin carbon-coated Fe1- xS nanoplates (Fe1- xS@C) is observed during the first discharge process of sodium-ion batteries, which leads to the formation of Fe1- xS nanoparticles with quantum size (≈5nm) tightly embedded in the carbon matrix. Surprisingly, no discernible aggregation phenomenon can be detected in subsequent cycles. In/ex situ experiments and theoretical calculations demonstrate that ultrafine pulverization can confer several advantages, including sustaining reversible conversion reactions, reducing the adsorption energies, and diffusion energy barriers of sodium atoms, and preventing the aggregation of Fe1- xS particles by strengthening the adsorption between pulverized Fe1- xS nanoparticles and carbon. As a result, benefiting from the unique ultrafine pulverization, the Fe1- xS@C anode simultaneously exhibits high reversible capacity (610mAhg-1 at 0.5Ag-1), superior rate capability (427.9mAhg-1 at 20Ag-1), and ultralong cycling stability (377.9mAhg-1 after 2500cycles at 20Ag-1).

Nitrogen doped, carbon coated (Zn0.71Mn0.29)Se/MnSe heterostructure as an anode for a fast-charging sodium ion battery

Nitrogen-doped, carbon-coated (Zn0.71Mn0.29)Se/MnSe porous nanospheres (Zn–Mn–Se@NC) were designed via a co-precipitation method and a vapor-phase selenization strategy, which maintained a capacity of 290 mAh/g for 5 A/g after 1000 cycles and 190 mAh/g at 10 A/g. The satisfied cycling performance was due to the porous nanosphere that relieve volume effect of electrode. Furthermore, the heterogeneous interface formed by (Zn0.71Mn0.29)Se and MnSe enhances thermodynamic stability and electrochemical reaction kinetics considerably, improving the electron/Na+ transfer rate. Furthermore, Zn–Mn–Se@NC, a bimetallic selenide, exhibits superior conductivity that improves the rate capacity of the Zn–Mn–Se@NC electrode. As an anode, the long-cycle and high-rate sodium-ion batteries using the Zn–Mn–Se@NC porous nanospheres have potential applications in electronic devices.

MoS2 Hollow Multishelled Nanospheres Doped Fe Single Atoms Capable of Fast Phase Transformation for Fast-charging Na-ion Batteries.

Low Na+ and electron diffusion kinetics severely restrain the rate capability of MoS2 as anode for sodium-ion batteries (SIBs). Slow phase transitions between 2H and 1T, and from NaxMoS2 to Mo and Na2S as well as the volume change during cycling, induce a poor cycling stability. Herein, an original Fe single atom doped MoS2 hollow multishelled structure (HoMS) is designed for the first time to address the above challenges. The Fe single atom in MoS2 promotes the electron transfer, companying with shortened charge diffusion path from unique HoMS, thereby achieving excellent rate capability. The strong adsorption with Na+ and self-catalysis of Fe single atom facilitates the reversible conversion between 2H and 1T, and from NaxMoS2 to Mo and Na2S. Moreover, the buffering effect of HoMS on volume change during cycling improves the cyclic stability. Consequently, the Fe single atom doped MoS2 quadruple-shelled sphere exhibits a high specific capacity of 213.3 mAh g-1 at an ultrahigh current density of 30 A g-1, which is superior to previously-reported results. Even at 5 A g-1, 259.4 mAh g-1 (83.68 %) was reserved after 500 cycles. Such elaborate catalytic site decorated HoMS is also promising to realize other "fast-charging" high-energy-density rechargeable batteries.

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

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

Enhanced Fast‐Charging and Longevity in Sodium‐Ion Batteries through Nitrogen‐Doped Carbon Frameworks Encasing Flower‐Like Bismuth Microspheres

AbstractMicro‐sized bismuth (Bi) is recognized for its high volumetric capacity and suitable working potential, making it a promising anode candidate for sodium‐ion batteries (SIBs). However, its substantial volume changes and slow reaction kinetics during cycling detrimentally affects the SIB performance. Theoretical prediction uncovers a previously unexplored favorable attribute that bonding between nitrogen within a carbon coating and Bi atoms facilitates Na+ ingress into the Bi bulk, significantly enhancing Bi‐Na alloying reactions, mitigating volume expansion, and preventing Na‐dendrite formation. Experimentally, the study innovatively engineers a flower‐like micro‐sized Bi encapsulated within an elastic, nitrogen‐doped carbon framework (FBi@NC) working as an efficient anode for SIBs. This design enables FBi@NC anode achieving a high tap density of 2.86 g cm−3 and delivering a remarkable volumetric capacity of 1100 mAh cm−3 at 1 mA cm−2. It also exhibits exceptional rate capability (368.2 mA h g−1 at 30 A g−1) and super durable cyclability (10 000 cycles with 318.8 mA h g−1 at 5 A g−1, retaining 82% capacity). Full cells with Na3V2(PO4)3 cathodes demonstrate superior rate and cycling performances. Crucially, this study elucidates the underlying Na+‐storage mechanisms and the contributory factors to performance enhancement, providing vital insights for the development of high‐energy and stable SIBs.

Pressure-Induced Defects and Reduced Size Endow TiO2 with High Capacity over 20 000 Cycles and Excellent Fast-Charging Performance in Sodium Ion Batteries.

Anatase TiO2 as sodium-ion-battery anode has attracted increased attention because of its low volume change and good safety. However, low capacity and poor rate performance caused by low electrical conductivity and slow ion diffusion greatly impede its practical applications. Here, a bi-solvent enhanced pressure strategy that induces defects (oxygen vacancies) into TiO2 via N doping and reduces its size by using mutual-solvent ethanol and dopant dimethylformamide as pressure-increased reagent of tetrabutyl orthotitanate tetramer is proposed to fabricate N-doped TiO2/C nanocomposites. The induced defects can increase ion storage sites, improve electrical conductivity, and decrease bandgap and ion diffuse energy barrier of TiO2. The size reduction increases contact interfaces between TiO2 and C and shortens ion diffuse distance, thus increasing extra ion storage sites and boosting ion diffusion rate of TiO2. The N-doped TiO2 possesses highly stable crystal structure with a slightly increase of 0.86% in crystal lattice spacing and 3.2% in particle size after fully sodiation. Consequently, as a sodium-ion battery anode, the nanocomposite delivers high capacity and superior rate capability along with ultralong cycling life. This work proposes a novel pressure-induced synthesis strategy that provides unique guidance for designing TiO2-based anode materials with high capacity and excellent fast-charging capability.

Heterogeneous engineering and carbon confinement strategy to synergistically boost the sodium storage performance of transition metal selenides

Transition metal selenides (TMSs) stand out as a promising anode material for sodium-ion batteries (SIBs) owing to their natural resources and exceptional sodium storage capacity. Despite these advantages, their practical application faces challenges, such as poor electronic conductivity, sluggish reaction kinetics and severe agglomeration during electrochemical reactions, hindering their effective utilization. Herein, the dual-carbon-confined CoSe2/FeSe2@NC@C nanocubes with heterogeneous structure are synthesized using ZIF-67 as the template by ion exchange, resorcin-formaldehyde (RF) coating, and subsequent in situ carbonization and selenidation. The N-doped porous carbon promotes rapid electrolyte penetration and minimizes the agglomeration of active materials during charging and discharging, while the RF-derived carbon framework reduces the cycling stress and keeps the integrity of the material structure. More importantly, the built-in electric field at the heterogeneous boundary layer drives electron redistribution, optimizing the electronic structure and enhancing the reaction kinetics of the anode material. Based on this, the nanocubes of CoSe2/FeSe2@NC@C exhibits superb sodium storage performance, delivering a high discharge capacity of 512.6 mA h g−1 at 0.5 A g−1 after 150 cycles and giving a discharge capacity of 298.2 mA h g−1 at 10 A g−1 with a CE close to 100.0 % even after 1000 cycles. This study proposes a viable method to synthesize advanced anodes for SIBs by a synergy effect of heterogeneous interfacial engineering and a carbon confinement strategy.

A composite material consisting of tin nanospheres anchored on and embedded in carbon nanofibers for outstanding sodium-ion storage

Benefiting from the abundant availability of sodium resources and the relative lower cost, sodium-ion batteries (SIBs) are increasingly garnering attention. However, there is a pivotal challenge in contemporary battery research, revolves around the advancement of electrode materials that are both high-performing and abundant in nature. Sn-based materials stand out as promising anodes in SIBs owing to the high theoretical capacity (847 mA h g−1) of metallic tin. Herein, a composite of Sn nanospheres anchored on and embedded in the carbon nanofibers (Sn@CNFs) has been synthesized by electrospinning and the following annealing process. After that, the Sn@CNFs was directly used as free-standing anodes for sodium-ion batteries. Remarkably, with assistance of K+ in the electrolyte, the Sn@CNFs anode sustains a capacity of 470.3 mA h g−1 over 450 cycles with a superb Coulombic efficiency (CE) of 99.71 %. Additionally, with a high cycle retention of 99.0 %, the Sn@CNFs||NVP full-cell delivers high charge and discharge capacity of 100.7 and 99.8 mA h g−1 at 0.1C after 50 cycles.

Titania/graphene nanocomposites from scalable gas-phase synthesis for high-capacity and high-stability sodium-ion battery anodes

In sodium-ion batteries (SIBs), TiO2 or sodium titanates are discussed as cost-effective anode material. The use of ultrafine TiO2 particles overcomes the effect of intrinsically low electronic and ionic conductivity that otherwise limits the electrochemical performance and thus its Na-ion storage capacity. Especially, TiO2 nanoparticles integrated in a highly conductive, large surface-area, and stable graphene matrix can achieve an exceptional electrochemical rate performance, durability, and increase in capacity. We report the direct and scalable gas-phase synthesis of TiO2 and graphene and their subsequent self-assembly to produce TiO2/graphene nanocomposites (TiO2/Gr). Transmission electron microscopy shows that the TiO2 nanoparticles are uniformly distributed on the surface of the graphene nanosheets. TiO2/Gr nanocomposites with graphene loadings of 20 and 30 wt% were tested as anode in SIBs. With the outstanding electronic conductivity enhancement and a synergistic Na-ion storage effect at the interface of TiO2 nanoparticles and graphene, nanocomposites with 30 wt% graphene exhibited particularly good electrochemical performance with a reversible capacity of 281 mAh g−1 at 0.1 C, compared to pristine TiO2 nanoparticles (155 mAh g−1). Moreover, the composite showed excellent high-rate performance of 158 mAh g−1 at 20 C and a reversible capacity of 154 mAh g−1 after 500 cycles at 10 C. Cyclic voltammetry showed that the Na-ion storage is dominated by surface and TiO2/Gr interface processes rather than slow, diffusion-controlled intercalation, explaining its outstanding rate performance. The synthesis route of these high-performing nanocomposites provides a highly promising strategy for the scalable production of advanced nanomaterials for SIBs.

Rod-like Ni-CoS2@NC@C: Structural design, heteroatom doping and carbon confinement engineering to synergistically boost sodium storage performance

Currently, conversion-type transition metal sulfides have been extensively favored as the anodes for sodium-ion batteries due to their excellent redox reversibility and high theoretical capacity; however, they generally suffer from large volume expansion and structural instability during repeatedly Na+ de/intercalation. Herein, spatially dual-confined Ni-doped CoS2@NC@C microrods (Ni-CoS2@NC@C) are developed via structural design, heteroatom doping and carbon confinement to boost sodium storage performance of the material. The morphology of one-dimensional-structured microrods effectively enlarges the electrode/electrolyte contact area, while the confinement of dual-carbon layers greatly alleviates the volume change-induced stress, pulverization, agglomeration of the material during charging and discharging. Moreover, the introduction of Ni improves the electrical conductivity of the material by modulating the electronic structure and enlarges the interlayer distance to accelerate Na+ diffusion. Accordingly, the as-prepared Ni-CoS2@NC@C exhibits superb electrochemical properties, delivering the satisfactory cycling performance of 526.6 mA h g−1 after 250 cycles at 1 A g−1, excellent rate performance of 410.9 mA h g−1 at 5 A g−1 and superior long cycling life of 502.5 mA h g−1 after 1,500 cycles at 5 A g−1. This study provides an innovative idea to improve sodium storage performance of conversion-type transition metal sulfides through the comprehensive strategy of structural design, heteroatom doping and carbon confinement.

Mechanochemical regulation of microcrystalline in coal-derived disordered carbon for improved sodium storage: Metamorphic grade

Coals are common precursors of the disordered carbon anodes for sodium ion batteries. In order to hinder the long-range ordered development of coal precursors during thermal conversion, the acid reagents and calcination under air atmosphere have been adopted in the pre-oxidation procedure, not in accordance with the demand of green energy storage. Herein, the mechanochemical pretreatment was employed to break the aromatic structures and generate the edge defects and oxygen functional groups on the coal surface, which would suppress the long-range ordered tendency and promote the introduction of nitrogen heteroatoms during following calcination. With the increasing metamorphic grades, the molecular rigidity of coal precursors increases owing to more highly polycondensed aromatic structures and less interior buffer space. The aromatic structures in the highest-ranked anthracite are broken most heavily during the mechanochemical process. Thus the nitrogen-doped anthracite-based carbon materials have the most disordered carbon structures and deliver a high reversible capacity of 323 mA h g−1 under 0.03 A/g after 90 cycles. This work provides a facile and green solution to fabricate the highly disordered carbon anodes with low cost and high performance from the industrial raw materials.

Electron Configuration Modulation Induced Stabilized 1T-MoS2 for Enhanced Sodium Ion Storage.

1T-MoS2 has become an ideal anode for sodium-ion batteries (SIBs). However, the metastable feature of 1T-MoS2 makes it difficult to directly synthesize under normal conditions. In addition, it easily transforms into 2H phase via restacking, resulting in inferior electrochemical performance. Herein, the electron configuration of Mo 4d orbitals is modulated and the stable 1T-MoS2 is constructed by nickel (Ni) introduction (1T-Ni-MoS2). The original electron configuration of Mo 4d orbitals is changed via the electron injection by Ni, which triggers the phase transition from 2H to 1T phase, thus improving the electrical conductivity and accelerating the redox kinetics of the material. Consequently, 1T-Ni-MoS2 exhibits superior rate capability (266.8 mAh g-1 at 10 A g-1) and excellent cycle life (358.7 mAh g-1 at 1 A g-1 after 350 cycles). In addition, the assembled Na3V2(PO4)3/C||1T-Ni-MoS2 full cells deliver excellent electrochemical properties and show great prospects in energy storage devices.

Fluidized Bed Chemical Vapor Deposition on Hard Carbon Powders to Produce Composite Energy Materials.

Herein, we report a general route for the uniform coating of hard carbon (HC) powders via fluidized bed chemical vapor deposition. Carbon-based fine powders are excellent substrate materials for many catalytic and electrochemical applications but intrinsically difficult to fluidize and prone to elutriation. The reactor was designed to achieve as much retention of powders as possible, supported by a computational fluid dynamics study to assess the hydrodynamic behavior for varying gaseous flow rates. Solutions of the tin seleno- and thio-ether complexes [SnCl4{nBuSe(CH2)3SenBu}] and [SnCl4{nBuS(CH2)3SnBu}] were used as single source precursors and injected at high temperature into a fluidized bed of HC powders under nitrogen flow. The method allowed for the synthesis of HC-SnSx-SnSe2 composites at the gram scale with potential applications in electrocatalysis and sodium-ion battery anodes.

Hard carbon with embedded graphitic nanofibers for fast-charge sodium-ion batteries

The development of fast-charging sodium-ion batteries need the anode to have a high rate capacity with a long and reversible charging plateau at low voltage (<0.1 V). Hard carbons are extensively investigated as the anodes for sodium-ion batteries, but slow charge-transfer kinetics and low reversible capacity at low potential region are still major obstacles for their practical applications. Herein, we develop a facile strategy via in-situ carbonization of the cross-linking network of bacterial cellulose and resin to synthesize hard carbons with intrinsically embedded graphitic nanofibers. The nanostructured hard carbons anodes have a reversible capacity of 345 mAh g−1 and an ultra-large low-voltage plateau capacity of 165.5 mAh g−1 (72.7% of the reversible capacity) at 2 A g−1. Kinetics and mechanism studies reveal that the embedded graphitic nanofibers greatly boost the charge transfer and ionic diffusion, i.e. the Na+ diffusion coefficient at the plateau region can be readily improved from ≈10−10.2 to ≈10−9.0 cm2 s−1. Evidence from in/ex-situ transmission electron microscopy (TEM) demonstrates that the graphic nanofibers, with an expanded interlayer spacing, provide sufficient diffusion channels for Na+ ions’ migration and storage. Full-cell sodium-ion batteries using the nanostructured hard carbon as anodes achieve superior fast-charge capability, showing great potential applications of the nanostructured hard carbon in the low-cost and environmentally friendly energy storage devices.

Strongly coupled C@MoSe2@OMWCNT heterostructure as an anode for sodium-ion batteries

MoSe2, with its extraordinary theoretical capacity, has emerged as a profoundly auspicious anode material for Sodium-ion Batteries (SIBs). However, the actual realization of SIBs encounters hurdles arising from insufficient electron and ion transportation capabilities, along with the irreversible transformation of Mo/Na2Se into MoSe2, eventually substituted by Mo/Se. In this investigation, By employing Mo-based complexes, we have achieved a triumphant synthesis of C@MoSe2@OMWCNT (oxidized multiwall carbon nanotubes) materials, wherein OMWCNTs serve as the fundamental substrate. Theoretical analysis has revealed that the utilization of OMWCNTs not only enhances the structural stability of the anode materials but also improves the electrical conductivity and Na+ ion mobility (the Na+ diffusion barrier: (MoSe2) 0.91 eV vs (C@MoSe2@OMWCNT) 0.41 eV) of the C@MoSe2@OMWCNT. These properties make C@MoSe2@OMWCNT a promising candidate for the development of high-performance SIBs. Furthermore, the Ex-situ Transmission Electron Microscopy (TEM) examination, unveils the emergence of Se and MoSe2 within the C@MoSe2@OMWCNT. The findings indicate that the outer carbon coating layer efficiently prevents contact between Se and the electrolyte, thereby impeding the formation of polyselenides. When C@MoSe2@OMWCNT is employed as the anode for the SIB, it exhibits exceptional cycle stability, with a capacity of 303 mA h g−1 and 189 mA h g−1 after 500 and 3000 cycles, respectively, under a current density of 5 A g−1. Overall, this investigation provides valuable insights into the design and synthesis of advanced anode materials for SIBs, which could have significant implications for the development of next-generation energy storage devices.

Novel titanium vanadate with superior Na+ transport kinetics for rapid charging and low-temperature sodium ion batteries

Sodium-ion batteries (SIBs) hold great promise for large-scale energy storage in the post-lithium-ion battery era due to their high rate performance and long lifespan, although their sluggish Na+ transformation kinetics still require improvement. Encouraged by the excellent electrochemical performance of titanium-based anode materials, here, we present a novel titanium vanadate@carbon (TVO@C) material as anode for SIBs. Our TVO@C material is synthesized via a facile coprecipitation method, with the following annealing process in an acetylene atomosphere. The opened ion channel and the oxygen vacancies within TVO@C facilitate the diffusion of Na+ ions, reducing their diffusion barrier. Thus, an ultrahigh rate of 100 A g−1 and long life of 10,000 cycles have been achieved. Furthermore, the TVO@C electrode exhibits stable performance, not only at room temperature, but also at temperatures as low as −20 °C. The TVO@C||Na3V2(PO4)3@C full cells have also achieved stable discharge/charge for 500 cycles. It is believed that this strategy provides new insight into the development of advanced electrodes and provides a new opportunity for constructing novel high rate electrodes.

Construction of robust solid-electrolyte interphase via electrode additive for high-performance Sn-based anodes of sodium-ion batteries

Alloy-based Sn anode for sodium-ion batteries has attracted tremendous attention due to its low working voltage, high specific capacity, and good availability. Its application is hindered, however, by inferior cycling stability due to its huge volume changes and unstable solid-electrolyte interphase (SEI) film. Herein, tetraphenylphosphonium bis(trifluoromethanesulfonyl)imide (TPPTFSI) is introduced into the electrode and spontaneously adsorbed on the surfaces of commercial Sn microparticles (μ-Sn) to improve the electrochemical performance of the Sn anode. In the first cycle, the TPP+ component of TPPTFSI decomposes to form an organic component of the SEI film, thereby enhancing its flexibility. Meanwhile, the TFSI− component is converted into an inorganic constituent of the SEI, improving its robustness and ionic conductivity. Therefore, the cycling performance of the μ-Sn is enhanced significantly. The modified electrode, TPPTFSI-Sn, delivers a capacity of 619.7 mAh g−1 after 2000 cycles at 2.0 A g−1, while the control sample can only survive for 30 cycles. Importantly, the full cell also exhibits excellent performance, including rate performance and cycling stability. Its simple operation and remarkable electrochemical performance improvement indicate the promising prospects of this strategy for advanced electrodes in SIBs.

Flame‐assisted ultrafast synthesis of functionalized carbon nanosheets for high‐performance sodium storage

AbstractThe unique structural features of hard carbon (HC) make it a promising anode candidate for sodium‐ion batteries (SIB). However, traditional methods of preparing HC require special equipment, long reaction times, and large energy consumption, resulting in low throughputs and efficiency. In our contribution, a novel synthesis method is proposed, involving the formation of HC nanosheets (NS‐CNs) within minutes by creating an anoxic environment through flame combustion and further introducing sulfur and nitrogen sources to achieve heteroatom doping. The effect of heterogeneous element doping on the microstructure of HC is quantitatively analyzed by high‐resolution transmission electron microscopy and image processing technology. Combined with density functional theory calculation, it is verified that the functionalized HC exhibits stronger Na+ adsorption ability, electron gain ability, and Na+ migration ability. As a result, NS‐CNs as SIB anodes provide an ultrahigh reversible capacity of 542.7 mAh g−1 at 0.1 A g−1, and excellent rate performance with a reversible capacity of 236.4 mAh g−1 at 2 A g−1 after 1200 cycles. Furthermore, full cell assembled with NS‐CNs as the can present 230 mAh g−1 at 0.5 A g−1 after 150 cycles. Finally, in/ex situ techniques confirm that the excellent sodium storage properties of NS‐CNs are due to the construction of abundant active sites based on the novel synthesis method for realizing the reversible adsorption of Na+. This work provides a novel strategy to develop novel carbons and gives deep insights for the further investigation of facile preparation methods to develop high‐performance carbon anodes for alkali‐ion batteries.

BF4- Tailoring Solvation Chemistry of Ether-Based Electrolytes to Construct Stable Electrode/Electrolyte Interfaces for Sodium-Ion Full Batteries.

The ether-based electrolytes show excellent performance on anodes in sodium-ion batteries (SIBs), but they still show poor compatibility with the cathodes. Here, ether electrolytes with NaBF4 as the main salt or additive were applied in NFM//HC full cells and showed enhanced performance than the electrolyte with NaPF6. Then, BF4- was found to have a stronger interaction with Na+, which could reduce the solvation of Na+ with the solvent, thus inducing the formation of the cathode electrolyte interface (CEI) and solid electrolyte interface (SEI) layers rich in inorganic species. Moreover, the morphology, structure, composition, and solubility of CEI and SEI were explored, concluding that NaBF4 could induce more stable CEI and SEI layers rich in B-containing species and inorganics. This work proposes using NaBF4 as the main salt or additive to improve the performance of ether electrolytes in NFM//HC full cells, which provides a strategy to improve the compatibility of ether-based electrolytes and cathodes.