High-performance Anode For Sodium-ion Batteries Research Articles

Interlayer-expanded MoS2 nanosheets/nitrogen-doped carbon as a high-performance anode for sodium-ion batteries

Abstract Sodium-ion batteries (SIBs) are considered promising energy storage devices owing to the abundant reserve and low-cost accessibility of Na resources. However, such batteries suffer from poor electrochemical performance due to the larger diameter of Na ions (0.106 nm). In this study, nitrogen-doped carbon-coating interlayer-expanded MoS2 porous nanosheets (MoS2@N–C) were synthesized, and their structural, morphological, and electrochemical properties were characterized. The XPS and EDS indicated the successful introduction of carbon into the MoS2 nanosheets. The interlayer spacing for (002) plane was increased from 0.62 nm to 0.78 nm corresponding to the shift toward lower angles shown in XRD. The MoS2@N–C exhibited an impressively high reversible capacity of 352 mAh/g at a current density of 100 mA/g after 200 cycles; this capacity is five times higher than that of bare MoS2. Moreover, MoS2@N–C showed excellent rate performance due to the boosted diffusion of Na ions. The observed improvement in the electrochemical performance of MoS2@N–C demonstrates that the combination of suitable composite materials and interlayer expansion are effective strategies for battery technologies based on the storage of large ions.

Spherical MoS2/Carbon Composite with Improved Electrochemical Performance for Sodium-Ion Battery Anode

Lithium-ion batteries (LIBs) with high energy density and long cycle life have been widely applied as the power sources in a variety of fields from portable electronic devices to large-scale energy storage systems (ESSs). Particularly in recent years, owing to the rapid growth of global electric vehicle and ESS markets, the cost of lithium source has risen sharply and many researchers predict a lithium shortage in the near future. In this regard, sodium-ion batteries (SIBs) have recently attracted growing attention because of low price and huge natural abundance of sodium, compared to lithium. However, the larger ionic radius of sodium ion (1.02 Å) than that of lithium (0.76 Å) results in poor electrochemical behaviors, which makes it difficult to find suitable anode materials for SIBs. [1] Among many proposed anode materials for SIBs, molybdenum disulfide (MoS2) is one of promising sodium-ion host materials because of its 2D-layered structure and high theoretical capacity of 670 mA h g-1. Despite these advantages, when used as an anode for SIBs, MoS2 exhibits several problems associated with low cycling stability and poor rate performance caused by large volume change during sodium insertion and extraction and low electrical conductivity. [2] In order to solve the aforementioned drawbacks of MoS2, herein, we present a spherical-shaped MoS2/carbon (MoS2/C) composite as a high-performance anode for SIBs. The spherical MoS2/C composites were synthesized by a facile and simple in situ wet chemical method using furfural as a surfactant as well as a carbon source. The as-prepared MoS2/C composite showed uniform distribution of MoS2 particles in the mesoporous carbonaceous matrix, which not only effectively alleviates large volume variation during repeated cycling, but also ensures high electrical conductivity. Owing to these benefits of good dispersion of active materials and the introduction of multifunctional matrix, the spherical MoS2/C composite electrodes demonstrated improved electrochemical performance such as enhanced cycle stability and superior rate capability. Furthermore, we believe that our facile and effective approach to synthesize MoS2/C composites can be extended to design and develop various transition metal-chalcogenides as promising and desirable anode candidates for SIBs.REFERENCE[1] Y. Xiao, S. H. Lee, Y. K. Sun, Adv. Energy Mater. 2017, 7, 1601329[2] Q. Pan, Q. Zhang, F. Zheng, Y. Liu, Y. Li, X. Ou, X. Xiong, C. Yang, M. Liu, ACS Nano 2018, 12, 12578. Figure 1

Chemical Grafting-derived N, P Co-doped Hollow Microporous Carbon Spheres for High-Performance Sodium-ion Battery Anodes

Microstructure design combined with high-level heteroatoms doping has been considered the leading approach for preparing the high-performance carbon anodes for sodium-ion batteries (SIBs). Herein, a hollow porous carbon sphere (NP-HPCS) that exhibits a high N, P co-doping level (6.05 at% for N, 5.19 at% for P) and a large microporous specific area (339 m2 g−1) is reported. The microporous and N, P co-doping synergistic construction of the NP-HPCS was achieved by a high-efficiency chemical grafting of hexachlorocyclotriphosphazene (HCCP) onto polydopamine (PDA) shell, accompanied by the in situ micellar transformation of pore-forming agent F127 in the grafting process. The as-prepared NP-HPCS used as an anode for SIBs delivers a superior rate capacity (~101 mAh g−1 at 20 A g−1) and an excellent long cycle performance (~120 mAh g−1 after 5000 cycles at 5 A g−1). The kinetics analysis and density functional theory (DFT) calculations were carried out to further analyze the superior sodium storage performance of NP-HPCS. Our work suggests an effective way to develop high-performance carbon anode materials for SIBs.

Zinc Phosphides as Outstanding Sodium-Ion Battery Anodes.

To design a high-performance sodium-ion battery anode, binary zinc phosphides (ZnP2 and Zn3P2) were synthesized by a facile solid-state heat treatment process, and their Na storage characteristics were evaluated. The Na reactivity of ZnP2 was better than that of Zn3P2. Therefore, a C-modified ZnP2-based composite (ZnP2-C) was fabricated to achieve better electrochemical performance. To investigate the electrochemical reaction mechanism of ZnP2-C during sodiation/desodiation, various ex situ analytical techniques were employed. During sodiation, ZnP2 in the composite was transformed into NaZn13 and Na3P phases, exhibiting a one-step conversion reaction. Conversely, Zn and P in NaZn13 and Na3P, respectively, were fully recombined to the original ZnP2 phase during desodiation. Owing to the one-step conversion/recombination of ZnP2 in the composite during cycling, the ZnP2-C showed high electrochemical performance with a highly reversible capacity of 883 mA h g-1 after 130 cycles with no capacity deterioration and a fast C-rate capability of 500 mA h g-1 at 1 C and 350 mA h g-1 at 3 C.

Green Synthesis of a Nanocrystalline Tin Disulfide-Reduced Graphene Oxide Anode from Ammonium Peroxostannate: a Highly Stable Sodium-Ion Battery Anode

We introduce a green synthesis approach for high-performance sodium-ion battery anodes that does not involve hydrothermal treatment or excessive energy use. Wet chemistry involving ammonium peroxostannate intermediate coating of reduced graphene oxide can be done at low temperature without excessive use of solvents. The process is practically waste-free and does not involve acid waste. Thermal treatment is required only for the solid material. The electrode exhibited very high stability and the charging capacity was reduced from 320 to 310 mA h g–1 after 2000 cycles at 3 A g–1. Moreover, the synthesis protocol demonstrated here is highly versatile with different, alternative pathways that provide many degrees of freedom in the process sheet design and in material composition.

N-Doped Biomass Carbon/Reduced Graphene Oxide as a High-Performance Anode for Sodium-Ion Batteries

For the further development of sodium-ion batteries (SIBs), it is very important to research and develop low-cost and high-performance anode materials. Though hard carbon has high theoretical capac...

In-situ growth of hybrid NaTi8O13/NaTiO2 nanoribbons on layered MXene Ti3C2 as a competitive anode for high-performance sodium-ion batteries

In the work, we successfully explore a two-step hydrothermal method for scalable synthesis of the hybrid sodium titanate (NaTi8O13/NaTiO2) nanoribbons well in-situ formed on the multi-layered MXene Ti3C2 (designed as NTO/Ti3C2). Benefiting from the inherent structural and componential superiorities, the resulted NTO/Ti3C2 composite exhibits long-duration cycling stability and superior rate behaviors when evaluated as a hybrid anode for advanced SIBs, which delivers a reversible and stable capacity of ∼82 mAh/g even after 1900 cycles at 2000 mA/g for SIBs.

Boosting the sodium storage performance of coal-based carbon materials through structure modification by solvent extraction

High-performance carbon anodes for sodium-ion batteries (SIBs) were synthesized with bituminous coal as precursor through solvent extraction and carbonization. The solvent extraction endows the coal-based carbon a hierarchical pore structure and enlarged interlayer distance, which can shorten the charge diffusion distance, alleviate the volume variation, and improve the ion diffusion rate. As a result, the modified coal-based electrodes exhibit impressive cycling stability (92% capacity retention after 7000th cycle at 2 A g−1) and excellent rate capability (79 mA h g−1 at 10 A g−1).

Highly microporous SbPO4/BCx hybrid anodes for sodium-ion batteries

An easy route was developed to fabricate a highly microporous SbPO4/BCx hybrid anode for high-performance sodium-ion batteries.

Dual-phase MoS2 as a high-performance sodium-ion battery anode

A dual-phase MoS2 with expanded interlayer distance is fabricated for sodium storage. The dual-phase MoS2 shows significantly improved electrical conductivity and enhanced Na+ diffusivity compared to the common 2H-MoS2.

Development of electrode architecture using Sb–rGO composite and CMC binder for high-performance sodium-ion battery anodes

Metallic antimony (Sb) is considered as a promising anode material for sodium-ion batteries (SIBs) owing to its high theoretical capacity (660 mAh/g) based on alloying/dealloying reactions with sodium ions. The main issues of Sb, however, are its large volume expansion upon cycling. In this study, we synthesized Sb-reduced graphene oxide (rGO) composite material by reduction of Sb2O3 nanoparticles. We confirmed that ~ 5 nm sized Sb nanoparticles are well distributed onto the rGO sheets, and Sb–rGO composite electrodes showed higher capacity and better cycling performance compared to bare Sb nanoplatelets. This improvement is attributed to increased electrical conductivity owing to incorporation of rGO, which also acts as a buffer against volume expansion of Sb particles during electrochemical reactions. The moderate rate performance of Sb–rGO composite materials was further improved by electrode formulation modification using a carboxymethylcellulose (CMC) binder. An electrode architecture containing Sb–rGO composite material with CMC binder achieved a high capacity (~ 400 mAh g−1) at a high rate (~ 30 C).

Hierarchical Tubular-Structured MoSe2 Nanosheets/N-Doped Carbon Nanocomposite with Enhanced Sodium Storage Properties.

Intimately coupled carbon/molybdenum-based hierarchical nanostructures are promising anodes for high-performance sodium-ion batteries owing to the combined effects of the two components and their robust structural stability. Mo-polydopamine (PDA) complexes are appealing precursors for the preparation of various Mo-based nanostructures containing N-doped carbon (NC). A facile method for the fabrication of hierarchical tubular nanocomposites with intimately coupled MoSe2 and NC nanosheets has been developed, which involves the preparation of Mo-PDA hybrid nanotubes through a chemical route followed by two heat treatments. The strong coupling between Mo anions and the catechol groups in dopamine not only restricts the crystallite size but also inhibits agglomeration during selenization, resulting in few-layered MoSe2 nanosheets embedded in hierarchical NC substrates. The as-synthesized nanotube composites are constructed by assembling primary MoSe2 /NC nanosheets. This unique structure not only increases the number of active sites but also shortens the diffusion length of ions and enhances the electronic conductivity of electrode materials. The as-synthesized hierarchical MoSe2 /NC nanotubes deliver a high capacity of 429 mAh g-1 at 1 A g-1 after the 150th cycle when used as anodes in sodium-ion batteries. Furthermore, at a high current density of 10 A g-1 , a high discharge capacity of 236 mAh g-1 is achieved.

Germanium telluride: Layered high-performance anode for sodium-ion batteries

Germanium telluride (GeTe) with a layered structure and a GeTe nanocomposite modified by amorphous carbon (GeTe/C) are prepared via a simple solid-state synthesis, and their electrochemical performance for sodium-ion batteries is evaluated. To determine the electrochemical sodiation/desodiation mechanism of the GeTe and GeTe/C, various ex situ analytical methods are employed. During sodiation, GeTe in both electrodes is converted into NaGe and Na2Te phases. By contrast, during desodiation, the converted NaGe and Na2Te phases in the only GeTe/C are completely recombined into the original GeTe phase. Because of the repeated conversion/recombination reactions during sodiation/desodiation, GeTe/C displays outstanding Na-ion storage characteristics, such as a high reversible first volumetric capacity of 662 mAh cm−3, a stable capacity retention of 98.5% up to after 100 cycles, and rapid rate capabilities of 704 mAh cm−3 at 1C and 630 mAh cm−3 at 3C. Therefore, the GeTe/C is expected to perform well as a high–capacity anode in rechargeable sodium-ion batteries.

(1 1 0)-Bridged nanoblocks self-assembled VS4 hollow microspheres as sodium-ion battery anode with superior rate capability and long cycling life

Development of three-dimensional self-assembled hollow nanoarchitectures combining functional shells and inner voids is an important approach for realizing high-rate and long-life battery electrodes. As a potential high-performance anode for sodium-ion batteries (SIBs), (1 1 0)-bridged nanoblocks self-assembled VS4 hollow microspheres (PNBH-VS4) are controllably synthesized by a facile one-step hydrothermal method. The (1 1 0)-bridged structure constructs the Na+ conducting channels and e− transfer paths among nano-grains and nanoblocks, and the self-assembled hollow structure presents the double space physical entrapment effect for the excessive volume change of nanoblocks, which synergistically improve the Na+ storage kinetics and structure stability. When employed as an anode for SIBs, PNBH-VS4 electrode exhibits the superior rate capability and long cycling life, outperforming those of the ever-reported VS4-based anode materials. At 0.2, 0.5, 1.0 and 2.0 A g−1, the capacity can reach 629, 564, 428 and 400 mAh g−1 after 250, 200, 350 and 700 cycles, respectively. Even at 5.0 A g−1, the capacity can still stabilize at 309 mAh g−1 after 1000 long cycles. In addition, it is revealed that PNBH-VS4 electrode undertakes the insertion and conversion reaction in the potential range of 0.50–3.00 and 0.05–0.50 V, respectively, where the main capacity contribution originates from the insertion reaction. Meanwhile, PNBH-VS4 electrode exhibits better insertion reversibility at lower current densities and conversion reversibility at higher current densities during cycling, respectively.

Sulfur-Doped TiO2 Anchored on a Large-Area Carbon Sheet as a High-Performance Anode for Sodium-Ion Battery.

Well-tailored sulfur-doped anatase titanium dioxide nanoparticles anchored on a large-area carbon sheet are designed, where the in situ sulfur-doped titanium dioxide directly comes from titanium oxysulfate and the large-area carbon sheet is derived from glucose. When applied as an anode material for sodium-ion batteries, it exhibits an excellent electrochemical performance including a high capacity [256.4 mA h g-1 at 2 C (1 C = 335 mA h g-1) after 500 cycles] and a remarkable rate of cycling stability (100.5 mA h g-1 at 30 C after 500 cycles). These outstanding sodium storage behaviors are ascribed to the nanosized particles (about 8-12 nm), good electronic conductivity promoted by the incorporation of carbon sheet and sulfur, as well as the unique chemical bond based on the electrostatic interaction.

Binder-free NaTi2(PO4)3 anodes for high-performance coaxial-fiber aqueous rechargeable sodium-ion batteries

Sodium superionic conductors-structured NaTi2(PO4)3 (NTP) is a significant anode material for high-energy-density aqueous rechargeable sodium-ion batteries (ARSIB) as result of its high capacity, abundant sources and suitable negative voltage plateau. Conventional synthesis of NTP with inevitable high-temperature treatment and subsequent slurry-casting procedure commonly lead to complicated high-cost process and reduced active sites. Thus, it is highly desirable yet significantly challenging to fabricate self-standing NTP-based electrodes. Herein, a simple solvothermal synthesis strategy is demonstrated to fabricate novel binder-free NTP-based electrodes without the need for any further post-synthesis treatment. As a proof-of-concept for applications, we successfully assemble a high-voltage coaxial-fiber ARSIB (CFARSIB). Taking advantages of the unique coaxial architecture and the synergy of novel electrode materials, the resulting CFARSIB exhibits a high capacity of 37.84 mAh cm−3 and an impressive energy density of 57.66 mWh cm−3. This work provides innovative insights and new possibilities to design binder-free NTP materials and will accelerate the development of high-performance wearable SIBs.

Zeolitic imidazolate frameworks derived ZnS/Co3S4 composite nanoparticles doping on polyhedral carbon framework for efficient lithium/sodium storage anode materials

High-performance lithium-ion batteries (LIBs) and sodium-ion battery (SIBs) anode materials Co3S4–ZnS/NC are prepared by carbonization and subsequent sulfidation using Co, Zn-based zeolitic imidazolate frameworks (ZIF) as a precursor. ZnS and Co3S4 in-situ doping on polyhedral carbon framework, which enhances the conductivity and can buffer the volume expansion during the cycle and improve the kinetics. When Co3S4–ZnS/NC use as an anode material for LIBs, which can deliver reversible capacity 750 mA h g−1 after 200 cycles at current density of 1 A g−1. It also exhibits excellent sodium storage, with capacities remaining 316.5 mA h g−1, after 1000 cycles at current density of 1 A g−1. Compared with pure ZnS/NC and Co3S4/NC electrode, the Co3S4–ZnS/NC electrode also exhibits enhanced rate performance in both Li/Na storage. This excellent performance may be due to the following factors. (a) The polyhedral carbon skeleton makes the composites has superior conductivity and excellent structural stability. (b) The large specific surface area and porous structure can make the electrolyte fully infiltrate the electrode. (c) The high capacitance contribution gives the composite excellent Li/Na storage performance, especially at high current density. These results reveal the potential application prospects of Co3S4–ZnS/NC in high performance LIBs and SIBs.

Hierarchical N-doping germanium/carbon nanofibers as anode for high-performance lithium-ion and sodium-ion batteries

Germanium (Ge) has gained a great deal of attention as an anode material for sodium ion batteries (SIBs) and lithium ion batteries (LIBs) for its high theoretical capacity and ion diffusivity. Unfortunately, Ge particle pulverization triggered by huge volume expansion during the alloying and dealloying processes can cause rapid capacity fade. Herein we report a facile method for the preparation of ultrafine Ge nanoparticles embedded in hierarchical N-doped multichannel carbon fibers (denoted as Ge-NMCFs) by electrospinning. The hierarchical carbon matrix not only provides sufficient internal void space to accommodate the large volume expansion of Ge nanoparticles, but also provides numerous open channels for the easy access of electrolyte and Na/Li ions. As half-cell tests revealed, the composite provides discharge capacity of 303 mA h g−1 (1st cycle) and 160 mA h g−1 (700th cycle) for SIBs, 1146.7 mA h g−1 (1st cycle) and 600 mA h g−1 (500th cycle) for LIBs at a current density of 500 mA g−1 (all the presented capacity based on the total weight of Ge/C composites). Density functional theory calculation suggests that N-doped in carbon can enhance the Na/Li ion storage and improve the electrochemical performance. This demonstration is an important step towards the development of SIBs and LIBs with much higher specific energy capacity and longer cycle stability.

Porous Hybrid Nanofibers Comprising ZnSe/CoSe₂/Carbon with Uniformly Distributed Pores as Anodes for High-Performance Sodium-Ion Batteries.

Well-designed porous structured bimetallic ZnSe/CoSe₂/carbon composite nanofibers with uniformly distributed pores were prepared as anodes for sodium-ion batteries by electrospinning and subsequent simple heat-treatment processes. Size-controlled polystyrene (PS) nanobeads in the electrospinning solution played a key role in the formation and uniform distribution of pores in the nanofiber structure, after the removal of selected PS nanobeads during the heat-treatment process. The porous ZnSe/CoSe₂/C composite nanofibers were able to release severe mechanical stress/strain during discharge–charge cycles, introduce larger contact area between the active materials and the electrolyte, and provide more active sites during cycling. The discharge capacity of porous ZnSe/CoSe2/C composite nanofibers at the 10,000th cycle was 297 mA h g−1, and the capacity retention measured from the second cycle was 81%. The final rate capacities of porous ZnSe/CoSe2/C composite nanofibers were 438, 377, 367, 348, 335, 323, and 303 mA h g−1 at current densities of 0.1, 0.5, 1, 3, 5, 7, and 10 A g−1, respectively. At the higher current densities of 10, 20, and 30 A g−1, the final rate capacities were 310, 222, and 141 mA h g−1, respectively.

Bismuth selenide nanocrystalline array electrodes for high-performance sodium-ion batteries

This work, for the first time, reports on the Bi2Se3 nanocrystal array wrapped by amorphous carbon layer as anode for high-performance sodium-ion batteries. In addition to a remarkable lithium storage capability, the Bi2Se3 nanocrystal array assembling onto flexible carbon cloth exhibits an outstanding cyclical stability for sodium ion batteries, which delivers a discharge capacity of 652.1 mAh g−1 at 100 mA g−1 (∼ a rate of 0.1 C) after 100 cycles. Even at 1 A g−1, a reversible capacity of 210.2 mAh g−1 can be maintained undergoing 200 charge-discharge cycles. The excellent cycle and rate capabilities of Bi2Se3 nanocrystal array could be attributed to the stable structure, fast ion migration channel and low charge transfer resistance for electrochemical processes. Detailed investigation reveals the appreciated reversibility of stepwise conversion and alloying reaction of Bi2Se3 nanocrystal array with high Coulombic efficiency and reversible capacity.