High-performance Anode For Sodium-ion Batteries Research Articles

Anthracite-based reduced graphene oxide/antimony composites as anode materials for high performance sodium ion batteries

As a viable alternative to lithium-ion batteries (LIBs), sodium ion batteries (SIBs) have attracted much more attentions. Herein, anthracite-based reduced graphene oxide/antimony (ARGO/SbX) composites have been successfully prepared as high performance anodes for SIBs. The anode composites have been synthesized by in situ reduction of Sb3+ provided by SbCl3 into Sb particles anchored onto the ARGO surface with the aid of NaBH4 and followed by annealing at 550 ℃ for 2 h. As designed, ARGO/SbX based SIBs can display high specific capacity, superior rate capability (527 mAh g−1 at 0.03 A g−1, 117 mAh g−1 at 10 A g−1), and good cycling stability (77 % of the initial capacity after 1000 cycles at 1 A g−1). The present research provides one low cost and high performance coal-based carbon anodes, which are supposed to accelerate the development of SIBs toward future large-scale applications.

MoS2-Decorated Graphene@porous Carbon Nanofiber Anodes via Centrifugal Spinning.

Sodium-ion batteries (SIBs) are promising alternatives to lithium-ion batteries as green energy storage devices because of their similar working principles and the abundance of low-cost sodium resources. Nanostructured carbon materials are attracting great interest as high-performance anodes for SIBs. Herein, a simple and fast technique to prepare carbon nanofibers (CNFs) is presented, and the effects of carbonization conditions on the morphology and electrochemical properties of CNF anodes in Li- and Na-ion batteries are investigated. Porous CNFs containing graphene were fabricated via centrifugal spinning, and MoS2 were decorated on graphene-included porous CNFs via hydrothermal synthesis. The effect of MoS2 on the morphology and the electrode performance was examined in detail. The results showed that the combination of centrifugal spinning, hydrothermal synthesis, and heat treatment is an efficient way to fabricate high-performance electrodes for rechargeable batteries. Furthermore, CNFs fabricated at a carbonization temperature of 800 °C delivered the highest capacity, and the addition of MoS2 improved the reversible capacity up to 860 mAh/g and 455 mAh/g for Li- and Na-ion batteries, respectively. A specific capacity of over 380 mAh/g was observed even at a high current density of 1 A/g. Centrifugal spinning and hydrothermal synthesis allowed for the fabrication of high-performance electrodes for sodium ion batteries.

Engineering carbon nanosheets with hexagonal ordered conical macropores as high-performance sodium-ion battery anodes

As one of the most promising candidates for sodium-ion battery anodes, hard carbons suffer from inferior rate performance owing to limited ion transfer rate and sluggish electrochemical kinetics. In this work, novel carbon nanosheets (CNS) with hexagonal ordered conical macropores are prepared. The CNS has a very thin thickness of approximately 370 nm, and the conical pores are penetrated through the whole nanosheet, forming well-connected ion transport freeway. In addition, the carbon microcrystal structure and interlayer spacing can be well tailored by adjusting the carbonization temperature, thereby controlling the sodium storage behavior of carbon electrodes. These structural merits endow CNS with accelerated ion transfer, minimized ion diffusion distance and fast electrochemical kinetics. Consequently, the CNS presents superior electrochemical performance. It delivers a high reversible capacity of 298 mAh g−1 at 0.1 A g−1; and after repeated charge/discharge for 500 times at 1 A g−1, its capacity remains 195 mA h g−1, with no rapid capacity loss. More importantly, CNS exhibits outstanding rate capability. Even under a very high current density of 2 A g−1, it still displays a large capacity of 210 mAh g−1, higher than most of state-of-the-art carbon anodes.

A 3D-Printed, Freestanding Carbon Lattice for Sodium Ion Batteries.

Increasing mass loadings of battery electrodes critically enhances the energy density of an overall battery by eliminating much of the inactive components, while compacting the battery size and lowering the costs of the ingredients. A hard carbon microlattice, digitally designed and fabricated by stereolithography 3D-printing and pyrolysis, offers enormous potential for high-mass-loading electrodes. In this work, sodium-ion batteries using hard carbon microlattices produced by an inexpensive 3D printer are demonstrated. Controlled periodic carbon microlattices are created with enhanced ion transport through microchannels. Carbon microlattices with a beam width of 32.8µm reach a record-high areal capacity of 21.3 mAh cm-2 at a loading of 98mg cm-2 without degrading performance, which is much higher than the conventional monolithic electrodes (≈5.2 mAh cm-2 at 92mg cm-2 ). Furthermore, binder-free, pure-carbon elements of microlattices enable the tracking of structural changes in hard carbon that support the hypothesized intercalation of ions at plateau regions by temporal ex situ X-ray diffraction measurements. These results will advance the development of high-performance and low-cost anodes for sodium-ion batteries as well as help with understanding the mechanisms of ion intercalations in hard carbon, expanding the utilities of 3D-printed carbon architectures in both applications and fundamental studies.

Cu9S5 nanoparticles encapsulated in N, S co-doped carbon nanofibers as anodes for high-performance lithium-ion and sodium-ion batteries

Copper sulfides (Cu x S) have gained increasing attention for using as anodes of rechargeable batteries owing to their high theoretical capacity and good electron conductivity. However, the structure instability and sluggish reaction kinetics seriously deteriorate their electrochemical performance. To tackle with these inherent drawbacks, an elaborate hierarchical architecture composed of N, S co-doped carbon nanofibers and well-dispersed Cu9S5 nanocrystallines (Cu9S5/CNFs) was fabricated. After sulfurization, the Cu9S5 nanoparticles that uniformly distributed on the CNFs surface are well-encapsulated inside the graphitic carbon shell. For the hierarchical Cu9S5/CNFs, the ion diffusion pathways can be shortened by the nano-sized Cu9S5 while the graphitized carbon shell can provide rapid electron transfer as well as accommodate the volume variation of Cu9S5 upon cycling. Additionally, the heteroatom within CNFs can provide abundant edges and defects for adsorbing lithium/sodium ions, thus boosting the reaction kinetics of batteries. Benefiting from all of these merits, the Cu9S5/CNFs composite obtained under 600 °C (Cu9S5/CNFs-600) used as anode for lithium-ion batteries (LIBs) demonstrates high specific capacity (709.2 mAh g−1 at 0.1 A g−1 after 100 cycles), good rate performance (509.1 mAh g−1 at 2 A g−1) and excellent durability (540.2 mAh g−1 at 1 A g−1 after 800 cycles with a ultrahigh capacity retention of 92.5%). And it also exhibits stable cycling performance (with a capacity retention of 90.5% after 1500 cycles at 1 A g−1) and excellent rate performance in sodium-ion batteries (SIBs). This work provides a promising strategy to prepare high-performance copper sulfides-based anode materials for LIBs and SIBs.

Superstructured Nanocrystals/Dual-Doped Mesoporous Carbon Anodes for High-Performance Sodium-Ion Batteries.

Two-dimensional ordered superstructures have been attracting considerable attention due to their interesting properties and potential applications. However, designing ideal functional superstructures with excellent electrochemical properties is still a major challenge, and an in-depth understanding of the structure-activity relationship of electrodes remains to be achieved. To elucidate this critical issue, herein, we rationally designed and synthesized for the first time superstructured TiO2/dual-doped mesoporous carbon anodes using confined space and surface coassembly strategies. Our method primarily relied on the larger interlayer space few-layered MXene and its negatively charged surface, allowing hexamethylenetetramine intercalation and surface electrostatic adsorption. The superstructured TiO2/dual-doped mesoporous carbon was successfully assembled by the thermal decomposition of a confined carbon precursor. Subsequently, the comparison of Na+-storage properties of various anodes was carried out based on the results of structural characterization techniques and electrochemical analysis methods. The results showed that the optimized anode (N/O-C@TiO2-20) can deliver a reversible capacity of 165 mA h g-1 after 1000 cycles at a current density of 1 A g-1, indicating excellent electrochemical properties. The enhancement can be attributed to the synergistic effect of carbon domains, defective nanocrystals, and a covalently coupled interface between TiO2 and mesoporous carbon. Our work not only offered a new strategy for the assembly and regulation of superstructures to promote the electrochemical performance but also enlightened the rational design of advanced anodes for sodium-ion battery application.

Microwave-assisted hydrothermal synthesis of three-dimensional NbOPO4-reduced graphene oxide-carbon nanotube composite for high performance sodium-ion battery anode

Sodium-ion batteries (SIBs) have aroused more and more academic and industrial interest due to their decent electrochemical performance and the cost-effectiveness of sodium (Na) resource. However, fabricating an appropriate anode material with high specific capacity, long-term cycle stability and superior rate capability remains a great challenge. Here, we adopt an efficient microwave-assisted hydrothermal method to prepare layered niobium oxyphosphate (NbOPO4) nanosheets, which grows on the single-walled carbon nanotubes (SWCNT) and reduced graphene oxide (rGO) (NbOPO4-rGO-SWCNT). Benefiting from three-dimensional hierarchical architecture combining NbOPO4 nanosheets with rGO-SWCNT framework with excellent electrical conductivity, NbOPO4-rGO-SWCNT electrode delivers a higher reversible specific capacity (323.2 mAh g−1 at 0.1 A g−1) and superior rate capability (147.9 mAh g−1 at 5 A g−1) than that of NbOPO4 (143.1/43.5 mAh g−1). Ex-situ X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements further reveal the electrochemical mechanism that reversible reaction between niobium phosphate (NbPO4) and niobium (Nb) occurs after the initial intercalation-conversion reaction, which contributes to the stable reversibility and high-rate capability in the following cycling. This work not only indicates that NbOPO4-rGO-SWCNT can act as a desirable anode material for SIBs, but also provide new insights to material design for niobium oxyphosphate composite.

Hard Carbon Microsphere with Built-In Electron Transport Channels as a High-Performance Anode for Sodium-Ion Batteries

Hard carbon is one of the most promising candidate materials as the anode for sodium-ion batteries (SIBs). In this work, we developed an effective strategy to homogenize highly conductive carbon nanotubes (CNTs) into a hard carbon microsphere (e-HC) to construct electron transport channels to improve the performance of hard carbon. The material featured a wrinkled hard carbon microsphere with built-in electron transport channels. Although the optimization made no significant changes in the particle size and the graphitization state for the hard carbon, the electrochemical performance was greatly improved in comparison with the pure hard carbon material without CNTs (HC). The increase in the electric and ionic conductivity was identified. The electrochemical measurements showed that the e-HC electrode delivered a reversible capacity of 335.6 mAh g−1 at 0.05 mA g−1, which was higher than that of the HC electrode (304.1 mAh g−1 at 0.05 mA g−1). The as-synthesized e-HC material exhibited a higher rate performance and a better cycle life than the HC material. The correlated mechanism for the enhancement was proposed in this study. The e-HC material can be used as a feasible anode for SIBs.

Self-supported TiO2@P nanotube arrays as high-performance anodes for sodium-ion batteries

Sodium-ion batteries (SIBs) have received widespread attention because of their scalability, low cost, and environmental advantages. Whereas, the low capacity and disappointing cycle capability of anode materials are unavoidable challenges, and high-capacity electrodes are accompanied by large volume expansion and cycle decay. Herein, self-supported TiO2 nanotube array nanocomposites are rationally designed by combining the stability of TiO2 and the high capacity of [Formula: see text]. The unique nanotube structure can effectively limit the expansion of phosphorus so that this anode has excellent reversibility and cycling. It affords a reversible capacity of 0.214 mAh cm[Formula: see text] at 0.08 mA cm[Formula: see text], a rate capability of 0.146 mAh cm[Formula: see text] at 1.6 mA cm[Formula: see text], and a stable cycling up to 5000 cycles.

Bean Pod-Like SbSn/N-Doped Carbon Fibers toward a Binder Free, Free-Standing, and High-Performance Anode for Sodium-Ion Batteries.

Bimetallic SbSn alloy stands out among the anode materials for sodium-ion batteries (SIBs) because of its high theoretical specific capacity (752 mAh g-1 ) and good electrical conductivity. However, the major challenge is the large volume change during cycling processes, bringing about rapid capacity decay. Herein, to cope with this issue, through electrostatic spinning and high temperature calcination reduction, the unique bean pod-like free-standing membrane is designed initially, filling SbSn dots into integrated carbon matrix including hollow carbon spheres and nitrogen-doped carbon fibers (B-SbSn/NCFs). Significantly, the synergistic carbon matrix not only improves the conductivity and flexibility, but provides enough buffer space to alleviate the large volume change of metal particles. More importantly, the B-SbSn/NCFs free-standing membrane can be directly used as the anode without polymer binder and conductive agent, which improves the energy density and reaction kinetics. Satisfyingly, the free-standing BSbSn/NCFs membrane anode shows excellent electrochemical performance in SIB. The specific capacity of the membrane electrode can maintain 486.9 mAh g-1 and the coulombic efficiency is close to 100% after 400 cycles at 100 mA g-1 . Furthermore, the full cell based on B-SbSn/NCFs anode also exhibits the good electrochemical performance.

Insight to Se-doping effects on Fe7S8/carbon nanotubes composite as anode for sodium-ion batteries

Iron based sulfides are considered as promising candidates for sodium-ion battery anodes. However, the inferior cyclic stability and poor capability hinder their practical application. In this study, a series of Se-doped Fe7S8 modified by carbon nanotubes (Fe7S8-xSex/CNTs) are synthesized through heat treatment and following selenization process. The composition of hybrids can be easily controlled by tuning the proportion of precursors. Electrochemical tests reveal that Fe7S8-xSex/CNTs with optimized nano-structure and composition displays improved sodium storage performances. Specifically, a discharge capacity of 303.4 mAh g−1 can be obtained at a high current of 4 A g−1. In addition, a remarkable capacity of 313.6 mAh g−1 is obtained after 1000 cycles at 2 A g−1, corresponding to a capacity retention of 67.7%. Sodium storage kinetic analysis suggests that Fe7S7Se1/CNTs electrode exhibit an enhanced capacitive-controlled process and improved sodium diffusion coefficient. Density functional theory (DFT) calculation results manifest that Fe7S7Se1 present a stronger binding energy with Na atoms and a decreased Na + diffusion barriers, which are responsible for the superior electrochemical performances. These results demonstrate that Se-doping of iron based sulfides may be a feasible strategy to develop high performance sodium-ion battery anodes.

Metal-organic framework derived CoSe2/N-doped carbon core-shell nanoparticles encapsulated in porous N-doped carbon nanotubes as high-performance anodes for sodium-ion batteries

Engineering ideal anode materials with low cost, considerable reaction kinetics and good structural stability are urgently needed for sodium-ion batteries (SIBs) toward large-scale applications. Here, a hierarchical peapod-like nanorod consisting of CoSe2/N-doped carbon (NC) core-shell nanoparticles (NPs) embedded into one-dimensional (1D) N-doped carbon nanotubes (CoSe2/NC@NCNTs) with inner void space is developed and fabricated by a self-template, dopamine-coating, and succeeding selenization strategy. In the cleverly designed CoSe2/NC@NCNTs composite, the 1D peapod-like structure provides high mechanical strength and allows for fast mass transport/electron transfer. The external NCNTs and inner void space can effectively accommodate volumetric undulation and restrain the aggregation of CoSe2 NPs. Based on these advantages, the CoSe2/NC@NCNTs electrode exhibits excellent comprehensive sodium storage performance, e.g., good rate capability (386.3 mAh g−1 at 10.0 A g−1) and high cycling stability (394.2 mAh g−1 up to 4500 loops at 5.0 A g−1). Moreover, the SIB full cells (Na3V2(PO4)3@C cathodes vs CoSe2/NC@NCNTs anodes) can achieve a reversible capacity of 75.6 mAh g−1total after 200 cycles at 0.5 A g−1. This work provides a feasible avenue to construct stable energy-storage materials.

Interlayer-Expanded MoS2 Nanoflowers Vertically Aligned on MXene@Dual-Phased TiO2 as High-Performance Anode for Sodium-Ion Batteries.

As a promising energy-storage and conversion anode material for high-power sodium-ion batteries operated at room temperature, the practical application of layered molybdenum disulfide (MoS2) is hindered by volumetric expansion during cycling. To address this issue, a rational design of MoS2 with enlarged lattice spacing aligned vertically on hierarchically porous Ti3C2Tx MXene nanosheets with partially oxidized rutile and anatase dual-phased TiO2 (MoS2@MXene@D-TiO2) composites via one-step hydrothermal method without following anneal process is reported. This unique "plane-to-surface" structure accomplishes hindering MoS2 from aggregating and restacking, enabling sufficient electrode/electrolyte interaction simultaneously. Meanwhile, the heterogeneous structure among dual-phased TiO2, MoS2, and MXene could constitute a built-in electric field, promoting high Na+ transportation. As a result, the as-constructed 3D MoS2@MXene@D-TiO2 heterostructure delivers admirable high-rate reversible capacity (359.6 mAh g-1 up to 5 A g-1) at room temperature, excellent cycling stability (about 200 mAh g-1) at a low temperature of -30 °C, and superior electrochemical performance in Na+ full batteries by coupling with a Na3V2(PO4)3 cathode. This ingenious design is clean and facile to inspire the potential of advanced low-dimensional heterogeneous structure electrode materials in the application of high-performance sodium-ion batteries.

Polyrrole-encapsulated Cu2Se nanosheets in situ grown on Cu mesh for high stability sodium-ion battery anode

PPy-encapsulated Cu 2 Se nanosheets in-situ grown on the Cu mesh (Cu 2 Se@PPy) acts as a high-performance anode for sodium-ion batteries, capable of delivering a high specific capacity of 293.0 mAh g −1 at 1.0 A g −1 , impressive rate capacity of 263.5 mAh g −1 under 10.0 A g −1 over 2000 cycles. • Cu 2 Se nanosheets were in-situ grown on Cu mesh at room temperature. • PPy coating layer enables robust structure stability and fast charge transport. • Cu 2 Se@PPy as a SIBs anode gives high specific capacity. • Cu 2 Se@PPy as a SIBs anode offers outstanding cycling durability. Copper selenide (Cu 2 Se) features high theoretical capacity and quasi-2D characteristics built by repeating sextuple layers of Se-Cu-Cu-Cu-Cu-Se, making it a fascinating anode for sodium-ion batteries (SIBs). However, it experiences huge volume variation during repeated discharge–charge processes. Here, a productive approach to preserve the structure of Cu 2 Se anode via in-situ coating conductive polymer carbon is proposed. As a demonstration, Cu 2 Se nanosheets encapsulated by polypyrrole (PPy) were anchored on Cu mesh (Cu 2 Se@PPy) and regarded as an electrode material for SIBs. The PPy shell enjoys double functions that improves the electronic conductivity as well as alleviates the significant volume swelling of Cu 2 Se. As a result, Cu 2 Se@PPy gives a satisfactory electrochemical performance, including high specific capacity of 293.0 mAh g −1 at 1.0 A g −1 , impressive rate capacity (263.5 mAh g −1 under 10.0 A g −1 over 2000 cycles). This work describes the uncomplicated approaches available for designing high stability metal selenides anodes for sodium storage.

Multi-heteroatom-doped hollow carbon nanocages from ZIF-8@CTP nanocomposites as high-performance anodes for sodium-ion batteries

Carbon-based material is one of the most promising candidates of anode materials for sodium-ion batteries (SIBs). However, the poor rate performance and low capacity due to intrinsic nature greatly impact their practical application. Heteroatom-doped carbon material is an efficient method to optimize the electrochemical performance of anode electrodes for SIBs. Herein, we report a template-initiated strategy to fabricate nitrogen, phosphorus, fluorine co-doped hollow carbon nanocages (NPF–HCN) derived from a rationally designed zeolitic imidazolate framework-8@covalent triazine polymer core-shell structured nanocomposites (ZIF-8@CTP). High proportions of tailored multi-heteroatom species within the CTP network contribute to the in-situ generation of N, P, F-doping in the resultant hollow carbon nanocages. Additionally, the hierarchical porous and hollow nanostructures of the NPF-HCN can promote the penetration of electrolytes, thus reduce diffusion barrier of Na+. As anode materials of SIBs, the as-prepared NPF-HCN delivers a higher initial capacity of 569.6 mA h/g at 1 A/g and a superior cycling behavior with a high capacity of 220.3 mA h/g at 5 A/g after 5000 cycles.

Bimetallic sulfide FeS2@SnS2 as high-performance anodes for sodium-ion batteries

Bimetallic sulfide FeS2@SnS2 as high-performance anodes for sodium-ion batteries

Hierarchical Porous and Sandwich-like Sulfur-Doped Carbon Nanosheets as High-Performance Anodes for Sodium-Ion Batteries

The development of high-performance carbon-based anodes for Na-ion batteries is highly desired but still remains challenging because of carbon materials with a low reversible capacity and poor cyclic performance. Herein, novel S-doped carbon nanosheets (SCNs) were prepared by a hydrothermal self-assembly process in the presence of graphene oxide (GO) as the matrix, starch as the carbon source, and dibenzyl disulfide as the sulfur source. The obtained SCNs with hierarchical pores and a sandwich-like structure were utilized as anode materials for Na-ion batteries, exhibiting a high reversible discharging capacity of 207.3 mAh g–1 after 100 cycles at 50 mA g–1. When the current density is up to 1 A g–1, a reversible discharge capacity of 118.8 mAh g–1 can also be acquired. Moreover, the prominent long-term cycling stability of more than 500 cycles can be obtained at 200 mA g–1. The outstanding electrochemical property (high reversible capacity, high rate performance, and long-term cycling stability) of the SCN electrode may be due to the synergistic effect of S doping, hierarchical pores, and the sandwich-like structure. Furthermore, electrochemical kinetic analysis also confirmed that the sodium storage mechanism of the SCN electrode reinforced pseudocapacitive-control behavior. The present study not only shows a high-performance anode material for Na-ion batteries but also provides a new method to prepare S-doped carbon materials for various applications.

Amorphous TiO2-x modified Sb nanowires as a high-performance sodium-ion battery anode

A simple synthesis has been proposed for seaweed-like amorphous TiO2-x modified Sb (a-TiO2-x/Sb) composite nanowires as sodium-ion battery (SIBs) anodes by a dealloying method of Al-Sb-Ti alloys. Compared with other conventional methods, this method has the advantages of simple preparation, high yield and easy large-scale synthesis. It is excitingly discovered that a-TiO2-x/Sb effectively alleviates volume changes and stabilizes the solid electrolyte interface (SEI). The a-TiO2-x/Sb nanowires electrodes deliver outstanding electrochemical performance based on the synergistic effects, exhibiting a high reversible capacity of 591.9 mA h g−1 at 100 mA g−1, stable cycling performance with a high capacity retention of 96.4% after 200 cycles and superior rate capability 382.2 mA h g−1 at 10,000 mA g−1, which is very competitive among the reported Sb-based anodes.

Molten Salt Synthesis of Carbon Anode for High-Performance Sodium-Ion Batteries

Molten Salt Synthesis of Carbon Anode for High-Performance Sodium-Ion Batteries

Bimetallic Bi-Sn microspheres as high initial coulombic efficiency and long lifespan anodes for sodium-ion batteries.

Anode materials with a high initial coulombic efficiency and a long lifespan are highly desirable for sodium-ion batteries. Here, bimetallic μ-BiSn microspheres well combine the high capacity of Sn and the good stability of Bi together, exhibiting superior electrochemical performance, such as a high initial Coulombic efficiency (90.6%), a good cycling stability (541 mA h g-1 after 3000 cycles at 2 A g-1) and an excellent rate capability (393 mA h g-1 at 10 A g-1).