Anode For Na-ion Batteries Research Articles

Enhanced cycling performances of hollow Sn compared to solid Sn in Na-ion battery

Hollow Sn nanostructures were obtained by simply controlling PVP addition in a solution-based reduction process. These nanostructures are assembled by many Sn nanoparticles with an inner void structure in the center. As an anode in Na-ion battery, the hollow Sn nanoparticles present improved cycling stability and capability in comparison with solid Sn nanoparticles, clearly indicating enhanced electrochemical properties for pure Sn anode in Na-ion battery. Moreover, their electrochemical impedance spectroscopy and charge/discharge profiles reveal the hollow structure not only maintains much higher capacity at large volumetric shrinkage process, but also provides structural stability and facilitated charge transfer in Sn anodes during the electrochemical reaction. Therefore, this hollow Sn nanostructure could provide new insight towards the exploration and design of alloy anode materials in Na-ion battery.

Carbon-coated Sb 2 Se 3 composite as anode material for sodium ion batteries

Abstract Carbon-coated Sb 2 Se 3 composite (Sb 2 Se 3 @C) is prepared via high energy mechanical milling accompanied with planetary milling method and investigated as a novel anode for Na-ion batteries for the first time. It exhibits a high Na-storage capacity of 650 mAh g − 1 at 0.1 A g − 1 , and maintains a reversible capacity of 624 mAh g − 1 with negligible capacity fading at 0.2 A g − 1 after 100 cycles, demonstrating a stable cycling performance. In addition, the ex situ XRD analysis reveals that the Na-storage mechanism of the Sb 2 Se 3 @C anode includes conversion reaction and alloying reaction.

Heteroatom-substituted carbon alloys for use in energy conversion and storage systems

Carbon-based materials containing heteroatoms, such as boron and nitrogen, are called heteroatom-substituted carbon alloys. Preparation and applications of heteroatom-substituted carbon alloys, particularly materials composed of boron, carbon and nitrogen (B/C/N materials), and carbon and nitrogen (C/N materials) are summarized in this review. Examples of potential applications of the materials to energy conversion and storage systems, such as secondary batteries, capacitors and photocatalysts are described. B/C/N materials can be intercalated with sodium (Na) to form a first stage intercalation compound, which can be used as the anode of Na ion batteries. C/N materials used as the electrode of capacitors have higher volumetric capacities than commercially-used activated carbon, and show photocatalytic behavior as an electrode for the production of hydrogen by the electrolysis of water. Important roles of boron and nitrogen in B/C/N and C/N materials are also discussed. TANSO 2015 (No. 267), 84–93.

SnO2 coated carbon cloth with surface modification as Na-ion battery anode

Sodium (Na)-ion batteries offer an attractive option for low cost large scale energy storage due to the earth abundance of Na. SnO2 is considered as a high capacity anode for Na-ion batteries with a theoretical capacity of 1378mAh/g. However, several limitations, such as large volume expansion with cycling, slow kinetics and low electrical conductance, have severely limited its performance. In this article, we demonstrate an anode consisting of a SnO2 nanocrystal layer grown on hierarchical microfibers of carbon cloth (CC) with extra surface coating to addresses the above challenges associated with SnO2 anodes. The soft nature of CC and the nanocrystal structure of SnO2 layers can effectively accommodate the volume change associated with the sodiation process. In addition, the effect from an extra coating layer of carbon (C/SnO2/CC) and Al2O3 (Al2O3/SnO2/CC) have been explored and the results showed that the extra coating layer can further enhance the performance of SnO2 anode. The C/SnO2/CC core–shell structure anode achieved a 501mAh/g and a 144mAh/g capacity at 0.1C and 30C charge/discharge rate, respectively. Meanwhile, a 375mAh/g specific capacity after 100 deep cycles with an 80% retention is achieved by Al2O3/SnO2/CC anode. The designed surface-coating/nanocrystal-active-material-layer/conductive-soft-platform core–shell system paves the way to high performance Na-ion batteries.

New Carbon Materials with Large Closed Pore Volume As Anode for High Energy Na-Ion Batteries

Recently demand for Li-ion batteries is growing as power sources for various applications such as electric vehicles and electric energy storage systems, because their high energy density and light weight properties are suitable for these applications. However, lithium resources may be insufficient to meet the increasing demand for these applications. Na-ion batteries could be a promising alternative to Li-ion batteries thanks to the natural abundance and lower cost of sodium. Non-graphitized carbon materials such as hard carbon are well-studied as high capacity anode materials for Na-ion batteries. The discharge capacity of 200 - 300 mAh/g, which is lower than conventional graphite anode materials for Li-ion batteries, has been reported [1,2]. In addition, the insertion mechanism of Na-ion into non-graphitized carbon materials is proposed that Na-ions are first inserted between stacked graphene layers in the voltage range from 2.0 V to 0.2 V (vs. Na metal), and then inserted into nano-pores in the voltage range from 0.2 V to 0.0 V (vs. Na metal) [2]. In this study, we focused on the pore structure of carbon materials and investigated the relationship between the carbon structures and electrochemical properties to clarify the optimum pore structure and propose a new carbon material as anode for high energy Na-ion batteries. Non-graphitized carbon samples were synthesized by heating various raw materials at between 1000 and 2600 °C under flowing argon. The pore structure of the synthesized carbon samples was characterized by using argon and nitrogen adsorption measurement and helium gas densitometry. Electrochemical properties were evaluated by using laminate-type cell with Na metals as the counter electrode and the reference electrode. Open and closed pore volumes of the synthesized carbons were calculated and the relationship between the reversible capacity and pore volume was investigated. As seen in Figure 1, an almost linear relationship between the reversible capacity in the voltage range from 0.2 to 0.0 V (vs. Na metal) and the closed pore volume was confirmed. Some carbon materials with large closed pore volume on the basis of this relationship were designed and successfully synthesized. Figure 2 shows charge/discharge curves of one of synthesized carbon samples. This carbon sample had the closed pore volume of 0.37 cc/g and its discharge capacity reached 413 mAh/g. This result suggests that Na-ion could be inserted reversibly in the closed pore and non-graphitized carbons with large closed pore volume may be promising for high capacity anode materials for Na-ion batteries. [1] D. A. Stevens et al, J. Electrochem. Soc., 148 (2001) A803 [2] S.Komaba et al, ACS Appl. Mater. Interfaces, 3 (2011) 4165 Figure 1

(Invited) Improving Cycle Life of High Capacity Alloy Anodes for Li-Ion and Na-Ion Batteries

The one critical challenge for development of high capacity electrodes in Li-ion batteries is the cycle life. Extensive efforts have been devoted to improve the cycling stability of Si, Sn, P and their compound anodes. The one of the most successful technology is the use of nanostructured materials. We used different strategy to enhance the cycle life of these high capacity anodes. In this talk, we will summarize our efforts in extending the cycle stability of Si, Sn, P and SnP3 anodes for Li-ion and Na-ion batteries.

FeSn5@Graphene Anodes for Li-Ion and Na-Ion Batteries

Intermetallic FeSn5 new phase has emerged as promising alternative material for application in lithium ion batteries (LIBs) due to its highest theoretical capacity of 929 mAh g−1 for the reported M(electrochemically inactive)-Sn intermetallic anodes. However, the cycling life and rate capacity of FeSn5 electrode materials still remains a great challenge. Herein, we report for the first time a facile strategy to synthesize such well-organized composite of nano-sized FeSn5 anchored on conducting graphene sheets as an advanced anode material for Li-ion and Na-ion batteries. The in situ synthesized FeSn5@graphene composite exhibits excellent cyclic stability and good rate capability which was ascribed to the structure of homogeneous distribution of FeSn5 nanospheres on graphene sheets that can improve electrical conductivity and accommodate structural stress due to its good conductivity, high surface area and mechanical flexibility. Further, the higher capacities of FeSn5@graphene composites in LIBs than that in SIBs is ascribed to the large Na-ion radius, resulting in slow Na-ion diffusion and large volume change upon sodium insertion/extraction reactions in SIBs. For comparison, bare graphene and FeSn5 nanocrystals were also prepared and investigated in detail.

Iso-Oriented Anatase TiO2 Mesocages as a High Performance Anode Material for Sodium-Ion Storage.

A major obstacle in realizing Na-ion batteries (NIBs) is the absence of suitable anode materials. Herein, we firstly report the anatase TiO2 mesocages constructed by crystallographically oriented nanoparticle subunits as a high performance anode for NIBs. The mesocages with tunable microstructures, high surface area (204 m2 g−1) and uniform mesoporous structure were firstly prepared by a general synthesis method under the assist of sodium dodecyl sulfate (SDS). It’s notable that the TiO2 mesocages exhibit a large reversible capacity and good rate capability. A stable capacity of 93 mAhg−1 can be retained after 500 cycles at 10 C in the range of 0.01–2.5 V, indicating high rate performance and good cycling stability. This could be due to the uniform architecture of iso-oriented mesocage structure with few grain boundaries and nanoporous nature, allowing fast electron and ion transport, and providing more active sites as well as freedom for volume change during Na-ion insertion. CV measurements demonstrate that the sodium-ion storage process of anatase mesocages is mainly controlled by pseudocapacitive behavior, which is different from the lithium-ion storage and further facilitates the high rate capability.

Sulfur covalently bonded graphene with large capacity and high rate for high-performance sodium-ion batteries anodes

Na-ion battery is playing an important role as a low-cost alternative power source to Li-ion battery. Developing novel carbonaceous anode materials is highly demanded for high performance and environmental benignity. We report, for the first time, the graphene sheets covalently bonded with sulfur atoms as Na-ion battery anode material with a large reversible capacity of 291mAhg−1 and an outstanding rate capability with 127 and 83mAhg−1 at 2.0 and 5.0Ag−1 (charging/discharging in 3.8 and 1min, respectively), and a long cycling stability as well. Both experiment and density functional theory calculation proves that the superior performance is mainly attributed to the unique nanoporous structure stemmed from the chemically S doping. This material holds great promise in future application of low cost, high-performance Na-ion batteries.

Efficient exfoliation N-doped graphene from N-containing bamboo-like carbon nanotubes for anode materials of Li-ion battery and Na-ion battery

Nanosize N-doped graphene is prepared from N-containing carbon nanotubes (CNTs) by chemical exfoliation. The CNTs adopted for graphene are characterized by a discontinuous wall that consists of nanosize graphite layers, exhibiting a bamboo-like appearance. Take advantage of this characterization, the most time-consuming process of chemical oxidation that involves intercalation in graphene from CNT has been markedly reduced. The reduction in processing time is attributed to the diffusion distance of chemical oxidation intercalation into nanosize graphite composed of a bamboo-like carbon nanotube (BCNT) wall being far less than that of conventional chemical exfoliation into microsize graphite. The as-prepared nanosize N-doped graphene from BCNTs has shown an excellent electrochemical performance for Li-ion battery and Na-ion battery anode materials.

Nanostructured polystyrene/polyaniline/graphene hybrid materials for electrochemical supercapacitor and Na-ion battery applications

In this work, nanostructured polystyrene/polyaniline/reduced graphene oxide (PS–PANI/rGO) hybrid materials based on in situ reduction of graphene oxide with ascorbic acid and self-assembly have been successfully prepared for electrochemical supercapacitor and Na-ion battery applications. The supercapacitor based on the PS–PANI/rGO as an electrode material exhibits a specific capacitance of 180 F g−1 at a current density of 0.5 A g−1 from −0.4 to 1.0 V and a high energy density of 49 W h kg−1 at the power density of 352.8 W kg−1. Moreover, the nanostructured PS–PANI/rGO has a good cycle stability (74 % capacitance retention after 5000 cycles), indicating its future potential application in electrochemical energy storage. The material is further used as an anode in Na-ion batteries, and the results show that the porous nanostructured PS–PANI/rGO delivers a high capacity of 155 mA h g−1 and keeps over 150 charge–discharge cycles at a constant current of 100 mA g−1 (0.5 C).

Characterisations and Electrochemical Performances of Hard Carbons in Sodium Ion Batteries

Nowadays, lithium ion (Li-ion) batteries are present in many applications such as mobile phones, computers, hybrid electric (HEV) and electric (EV) vehicles. However abundance, cost and especially accessibility of lithium may bring some issues for Li-ion development in the future [1]. This leads the scientist community to go back to sodium ion battery research, which stopped because of Li ion battery success in the 80’s. Sodium seems to be an interesting alternative to lithium because of its abundance and availability. However, in order to be competitive to other technologies in stationary domain, for instance, capacity, rate capability and cycle life should be improved [2]. Carbons have been extensively studied in the literature as Na-Ion anodes: hard carbons, carbon black, carbon nanospheres, carbon fibers and graphene. Carbon nanotubes made from polyaniline pyrolysis showed interesting performances. A reversible capacity of 250 mAh/g at a current density of 50 mA/g was obtained with 82% of capacity retention after 400 cycles. However the initial coulombic efficiency remains very low (around 50%) [3]. Ding et al. [4] tested carbon made from peat pyrolysis as anode for Na ion batteries. They obtained a reversible capacity of 255mAh/g after 200 cycles with a current density equal to 50 mA/g. In our study, hard carbons (HC) were made from cellulose. Different final pyrolysis temperatures were studied from 700°C to 1600°C. Characterisation methods such as Small Angle X ray Scattering (SAXS) measurements; isotherms and Transmission Electron Microscopy (TEM) were performed in order to understand the impact of pyrolysis temperature on carbon structure. This parameter plays a major role on external and internal porosities. Different electrochemical tests were performed to study stability and rate capability of the samples. Figure 1 shows the cycling performances of the sample pyrolysed at 1400°C. In our presentation, we propose to highlight the characterisations performed on these hard carbons. TEM images could clearly show the different graphene sheet arrangements. With the tests performed on Na//HC cells, we will try to correlate hard carbon structure to electrochemical performances. Perspectives on future studies will be also exhibited.

Designed Synthesis of SnO2 Nanosheet Arrays with Superior Performance for Lithium and Sodium Storage

Room-temperature rechargeable sodium-ion batteries (SIBs) are receiving increasing attention for upcoming large-scale applications in smart grid and electric vehicles due to the earth abundance and low cost of sodium.1, 2 However, Na ion has a larger radius of 1.02 Å (~55% larger than Li+, 0.76 Å) and three times heavier than lithium (23 g mol-1 compared with 6.9 g mol-1), which directly affects the Na+ insertion/deinsertion in electrochemical process, leading to low reversible capacity, poor cycling stability, inferior rate capability.3 Although reversible sodium intercalation into commercial graphite anodes was demonstrated by using diglyme-based electrolyte or chemically modified graphite recently, the specific capacity is still lower than that of lithium ion batteries.4, 5Therefore, it is highly promising to develop high capacity anode materials based new storage mechanisms toward practical application of SIBs. Fig. 1 (a) XRD pattern, (b-d) SEM images of SnO2 nanosheet arrays grown on the carbon fiber paper. Herein, we report a simple solution-based hydrothermal approach to construct hybrid architectures by growing 2D hierarchical SnO2 nanosheet arrays on conductive flexible carbon substrates as the anode for Na-ion and Li-ion batteries. Fig. 1a shows the X-ray diffraction (XRD) pattern of the SnO2 nanosheet arrays, and all the diffraction peaks can be readily indexed to the tetragonal phase of SnO2 (JCPDS Card no.71-0652). Two peaks at around 26.2° and 43.1° marked with asterisk originate from the carbon textiles.6 Scanning electron microscopy (SEM) images shown in Fig1b-d clearly display ultrathin SnO2 nanosheet arrays uniformly cover carbon substrates and interconnect with each other to form highly open and porous structure. Taking merits of the ultrathin and highly conductive nature of SnO2 nanosheets as well as the porous interconnected three-dimensional nanoarchitectures, the binder-free flexible SnO2electrodes exhibit high specific capacity with enhanced cycling stability, making it a promising anode material for electrochemical energy storage devices application. Acknowledgements The authors are grateful for financial support from the National Program on Key Basic Research Project of China (973 Program, no. 2014CB239701), National Natural Science Foundation of China (no. 21173120, 51372116), Natural Science Foundations of Jiangsu Province (no.BK2011030), Funding for Outstanding Doctoral Dissertation in NUAA (no.BCXJ14-12), Founding of Graduate Innovation Center in NUAA (no. kfjj201438), and Funding of Jiangsu Innovation Program for Graduate Education (no.KYLX_0254) and the Fundamental Research Funds for the Central Universities.

Aerosol-assisted rapid synthesis of SnS-C composite microspheres as anode material for Na-ion batteries

SnS-C composite powders were prepared through one-pot spray pyrolysis for use as anode materials for Na-ion batteries. C microspheres with uniformly attached cubic-like SnS nanocrystals, which have an amorphous C coating layer, were formed at a preparation temperature of 900 °C. The initial discharge capacities of the bare SnS and SnS-C composite powders at a current density of 500 mA·g−1 were 695 and 740 mA·h·g−1, respectively. The discharge capacities after 50 cycles and the capacity retentions measured from the second cycle of the bare SnS and SnS-C composite powders were 25 and 433 mA·h·g−1 and 5 and 89%, respectively. The prepared SnS-C composite powders with high reversible capacities and good cycle performance can be used as Na-ion battery anode materials.

Nb-doped rutile TiO₂: a potential anode material for Na-ion battery.

The electrochemical properties of the rutile-type TiO2 and Nb-doped TiO2 were investigated for the first time as Na-ion battery anodes. Ti(1-x)Nb(x)O2 thick-film electrodes without a binder and a conductive additive were prepared using a sol-gel method followed by a gas-deposition method. The TiO2 electrode showed reversible reactions of Na insertion/extraction accompanied by expansion/contraction of the TiO2 lattice. Among the Ti(1-x)Nb(x)O2 electrodes with x = 0-0.18, the Ti(0.94)Nb(0.06)O2 electrode exhibited the best cycling performance, with a reversible capacity of 160 mA h g(-1) at the 50th cycle. As the Li-ion battery anode, this electrode also attained an excellent rate capability, with a capacity of 120 mA h g(-1) even at the high current density of 16.75 A g(-1) (50C). The improvements in the performances are attributed to a 3 orders of magnitude higher electronic conductivity of Ti(0.94)Nb(0.06)O2 compared to that of TiO2. This offers the possibility of Nb-doped rutile TiO2 as a Na-ion battery anode as well as a Li-ion battery anode.

High capacity group-15 alloy anodes for Na-ion batteries: Electrochemical and mechanical insights

Group-15 elements phosphorus, arsenic, antimony and bismuth offer the prospect of serving as functional alloying elements for developing high-capacity alloy anodes for sodium-ion batteries (NIBs). Here we obtain concentration-dependent electrochemical properties of sodium (Na) alloys with group-15 elements using first principles calculations. Since Na intercalation in these alloys is accompanied by a substantial volume expansion that can lead to mechanical failure and loss of capacity, we have also obtained a full set of concentration-dependent elastic properties for a single crystal as well as a polycrystalline microstructure. We find that sodiation of these alloys results in their significant elastic softening by as large as 60%. In contrast to the group-14 alloys that are also being explored as anodes of NIBs, the elastic softening in group-15 alloys varies in a non-monotonic manner with Na concentration, and more importantly, the maximum degradation of elastic properties does not necessarily occur at full sodiation. Our results provide crucial insights into the electrochemical and mechanical response of these alloys to Na intercalation, thus contributing to the design of failure-resistant architectures of high capacity NIBs.

Electrochemical properties of tin oxide anodes for sodium-ion batteries

Few tin (Sn)-oxide based anode materials have been found to have large reversible capacity for both sodium (Na)-ion and lithium (Li)-ion batteries. Herein, we report the synthesis and electrochemical properties of Sn oxide-based anodes for sodium-ion batteries: SnO, SnO2, and SnO2/C. Among them, SnO is the most suitable anode for Na-ion batteries with less first cycle irreversibility, better cycle life, and lower charge transfer resistance. The energy storage mechanism of the above-mentioned Sn oxides was studied, which suggested that the conversion reaction of the Sn oxide anodes is reversible in Na-ion batteries. The better anode performance of SnO is attributed by the better conductivity.

Recent Development on Anodes for Na‐Ion Batteries

AbstractNew discoveries in anode materials for sodium ion batteries (NIBs) are highly necessary to achieve the goals of widespread applications, such as electric vehicles (EVs) and grid‐level energy storage. Carbon‐based materials are critical for this task as they are inexpensive, abundant, and versatile. They contain a plethora of structures and morphologies, ranging from highly ordered graphite or nanotubes to highly disordered amorphous carbon, thus making them very attractive for electrochemical energy storage. This review attempts to cover past and recent progress in the development of carbon‐based anode materials for NIBs. To give a larger context, the article will briefly cover other anode materials for NIBs as well. The aim of this paper is to provide a timely update for researchers currently involved in the respective fields or to serve as a starting point for individuals who would like to gain a greater knowledge of new NIB anode materials.

Low-surface-area hard carbon anode for na-ion batteries via graphene oxide as a dehydration agent.

Na-ion batteries are emerging as one of the most promising energy storage technologies, particularly for grid-level applications. Among anode candidate materials, hard carbon is very attractive due to its high capacity and low cost. However, hard carbon anodes often suffer a low first-cycle Coulombic efficiency and fast capacity fading. In this study, we discover that doping graphene oxide into sucrose, the precursor for hard carbon, can effectively reduce the specific surface area of hard carbon to as low as 5.4 m(2)/g. We further reveal that such doping can effectively prevent foaming during caramelization of sucrose and extend the pyrolysis burnoff of sucrose caramel over a wider temperature range. The obtained low-surface-area hard carbon greatly improves the first-cycle Coulombic efficiency from 74% to 83% and delivers a very stable cyclic life with 95% of capacity retention after 200 cycles.

Structure of H2Ti3O7 and its evolution during sodium insertion as anode for Na ion batteries.

H2Ti3O7 was prepared as a single phase material by ionic exchange from Na2Ti3O7. The complete ionic exchange was confirmed by (1)H and (23)Na solid state Nuclear Magnetic Resonance (NMR). The atomic positions of H2Ti3O7 were obtained from the Rietveld refinement of powder X-ray diffraction (PXRD) and neutron diffraction experimental data, the latter collected at two different wavelengths to precisely determine the hydrogen atomic positions in the structure. All H(+) cations are hydrogen bonded to two adjacent [Ti3O7](2-) layers leading to the gliding of the layers and lattice centring with respect to the parent Na2Ti3O7. In contrast with a previous report where protons were located in two different positions of H2Ti3O7, 3 types of proton positions were found. Two of the three types of proton are bonded to the only oxygen linked to a single titanium atom forming an H-O-H angle close to that of the water molecule. H2Ti3O7 is able to electrochemically insert Na(+). The electrochemical insertion of sodium into H2Ti3O7 starts with a solid solution regime of the C-centred phase. Then, between 0.6 and 1.2 inserted Na(+) the reaction proceeds through a two phase reaction and a plateau at 1.3 V vs. Na(+)/Na is observed in the voltage-composition curve. The second phase resembles the primitive Na2Ti3O7 cell as detected by in situ PXRD. Upon oxidation, from 0.9 to 2.2 V, the PXRD pattern remains mostly unchanged probably due to H(+) removal instead of Na(+), with the capacity quickly fading upon cycling. Conditioning H2Ti3O7 for two cycles at 0.9-2.2 V before cycling in the 0.05-1.6 V range yields similar specific capacity and better retention than the original Na2Ti3O7 in the same voltage range.