Sodium Storage Materials Research Articles

Amorphous P2S5/C Composite as High-Performance Anode Materials for Sodium-Ion Batteries.

We show a general method for achieving high-performance sodium storage materials via transforming crystalline P2S5 to amorphous P2S5 adhered to carbon matrix. The amorphous P2S5/C composite shows unique structural characteristics differing from the crystalline, which is identified by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscope (TEM) and so on. The amorphous P2S5/C composite exhibits a safe average potential of 0.82 V, a reversible capacity of 400 mA h g-1, a remarkable capacity retention of 89.4% over 4000 cycles as well as good rate capability. Our findings open up opportunities to design of advanced anodes for room-temperature sodium-ion batteries.

Rapid redox kinetics in uniform sandwich-structured mesoporous Nb2O5/graphene/mesoporous Nb2O5 nanosheets for high-performance sodium-ion supercapacitors

Sodium-ion hybrid supercapacitors have received great attracts for next-generation energy storage applications due to their high energy and power densities, as well as the abundant sodium resource. However, electrodes based on transition-metal oxides often suffer from low reversible capacity and sluggish redox kinetics, which seriously constrains the rate and cycling performance of the devices. Herein, a facile two-step hydrolysis synthesis is used to prepare uniform sandwich-like mesoporous Nb2O5/graphene/mesoporous Nb2O5 (G@mNb2O5) nanosheets as sodium storage materials. The mesoporous Nb2O5 layers on graphene are constructed by several nanometer-sized Nb2O5 particles. In virtue of the structural features, the G@mNb2O5 nanosheets electrode demonstrates high-rate capacity (293 and 125mAhg−1at 50 and 2000mAg−1, respectively) and stable cycling performance due to the rapid redox kinetics, including significantly increased surface pseudocapacitive contribution, improved sodium-ion diffusion coefficient, and short characteristic relaxation process. By employing activated carbon as cathode, a full sodium-ion hybrid device successfully demonstrates a high energy density of 56.1Whkg−1 at 120Wkg−1, and 9.7Whkg−1 at 7200Wkg−1, as well as a stable capacitance retention of ∼ 89% at 1Ag−1. The availability of capacitive Na-ion storage system presented here is attractive for cost-effective energy storage applications.

Heterogeneous Ti3SiC2@C-Containing Na2Ti7O15 Architecture for High-Performance Sodium Storage at Elevated Temperatures.

Rational design of heterogeneous electrode materials with hierarchical architecture is a potential approach to significantly improve their energy densities. Herein, we report a tailored microwave-assisted synthetic strategy to create heterogeneous hierarchical Ti3SiC2@C-containing Na2Ti7O15 (MAX@C-NTO) composites as potential anode materials for high-performance sodium storage in a wide temperature range from 25 to 80 °C. This composite delivers first reversible capacities of 230 mAh g-1 at 200 mA g-1 and 149 mAh g-1 at 3000 mA g-1 at 25 °C. A high capacity of ∼93 mAh g-1 without any apparent decay even after more than 10 000 cycles is obtained at an ultrahigh current density of 10 000 mA g-1. Moreover, both a high reversible capacity and an ultralong durable stability are achieved below 60 °C for the same composites, wherein a 75.2% capacity retention (∼120 mAh g-1 at 10 000 mA g-1) is achieved after 3000 cycles at 60 °C. To the best of our knowledge, both the sodium storage performances and the temperature tolerances outperform those of all the Ti-based sodium storage materials reported so far. The superior sodium storage performances of the as-synthesized composites are attributed to the heterogeneous core-shell architecture, which not only provides fast kinetics by high pseudocapacitance but also prolongs cycling life by preventing particle agglomeration and facilitates the transportation of electrons and sodium ions by large micro/mesopore structure.

Incorporation of Co into MoS2/graphene nanocomposites: One effective way to enhance the cycling stability of Li/Na storage

Layered transition metal dichalcogenides are promising as lithium and/or sodium storage materials for lithium and sodium (Li/Na) ion batteries. However they always exhibit limited rate capability and long-term cycling stability, due to the fact that their 2D structures are easily restacking and agglomeration during cycling process and further result poor electrochemical reversibility. Herein, hierarchical Co1/3Mo2/3S2/graphene nanocomposites without CoSx and MoS2 impurities have been synthesized via one-pot solvothermal process. The incorporation of Co into MoS2 at atomic level can not only give rise to thinner and smaller nanosheets in the nanocomposites than MoS2/graphene nanocomposites, but also significantly decrease the size of in-situ formed MoS2/CoSx nanoparticles during electrochemical conversion process, which can greatly promoting the ion diffusion and suppressing the aggregation of active materials. Furthermore, the conductivity of Co1/3Mo2/3S2/graphene nanocomposites can be enhanced from 0.46 S m−1 (MoS2/graphene) to 1.39 S m−1via changing the semiconducting MoS2 to metallic Co1/3Mo2/3S2. The simultaneously optimized electron conductivity and ions diffusion dynamics of Co1/3Mo2/3S2/graphene nanocomposites can effectively improve the reversibility of electrochemical conversion reactions. A capacity of 940 mAh g−1 and 529 mAh g−1 can be maintained at 3200th cycle (2 A g−1) in lithium-ion batteries and 200th cycle (1 A g−1) in sodium-ion batteries, respectively.

Discussion on the mechanism of sodium storage of different structural types of carbon material

Because of its rich resources and cost advantages, sodium-ion battery has attracted increasing attention in the field of large-scale energy storage. Similar to the lithium-ion battery anode, carbon materials are the most widely studied sodium storage anode materials. However, carbon materials have diverse structures relied on the treatment conditions, resulting in differences in the properties of sodium storage and even the different sodium storage mechanisms. In order to study the relationship between the carbon structure and its storage behavior, this paper comprehensively analyzes the structural characteristics and sodium storage behavior of different carbon materials, discusses the possible electrochemical mechanism, and makes possible analysis of some existing controversial areas. And this paper can also provide a reference for the development of high performance carbon-based sodium storage materials.

Dual-textured Prussian Blue nanocubes as sodium ion storage materials

Sodium ion batteries are being highlighted as a promising energy storage system to resolve the critical issues associated with lithium ion battery usage due to a limited quantity of lithium resources on the earth. Although recent advances in sodium ion battery technology have been remarkable, the reversible capacities and cyclic performance of sodium ion batteries should be further advanced prior to their successful implementation. Herein, we demonstrate dual-textured Prussian blue nanocubes prepared via simple acid etching as a reliable sodium storage material. Taking advantage of their hybrid microstructure composed of porous and non-porous domains, dual-textured Prussian blue nanocubes exhibit high reversible capacities, good rate capabilities, and stable cyclic performance. Moreover, the nanocubes exhibit excellent dimensional stability even after 100 cycles, offering new opportunities for the development of robust and high-performance sodium rechargeable batteries.

Synthesis of carbon coated Bi 2 O 3 nanocomposite anode for sodium-ion batteries

Abstract Bi 2 O 3 is a promising sodium storage material due to its high gravimetric specific capacity. However, Bi 2 O 3 possesses lower electrochemical performance due to its poor electrical conductivity and structural integrity during Na + insertion/extraction process. Here, we prepared a carbon coated Bi 2 O 3 nanocomposite by a redox reaction and a carbon coating process. In this nanocomposite, the carbon layer can avoid the direct contact between Bi 2 O 3 and electrolyte, which inhibits the repeated formation and decomposition of solid electrolyte interface film. Additionally, the carbon layer can enhance the electrical conductivity of Bi 2 O 3 and suppress its aggregation due to its volume change during charge and discharge process. In addition, nano-sized Bi 2 O 3 can reduce the transport distance of Na + and electron. The nanocomposite shows excellent cycling performance and rate capability as anode for sodium-ion batteries. A high capacity of 421 mAh g −1 can be maintained after 100 cycles at 1500 mA g −1 and 392 mAh g −1 can be shown at 3200 mAh g −1 .

Pseudocapacitive Sodium Storage in Mesoporous Single-Crystal-like TiO2-Graphene Nanocomposite Enables High-Performance Sodium-Ion Capacitors.

Sodium-ion capacitors can potentially combine the virtues of high power capability of conventional electrochemical capacitors and high energy density of batteries. However, the lack of high-performance electrode materials has been the major challenge of sodium-based energy storage devices. In this work, we report a microwave-assisted synthesis of single-crystal-like anatase TiO2 mesocages anchored on graphene as a sodium storage material. The architecture of the nanocomposite results in pseudocapacitive charge storage behavior with fast kinetics, high reversibility, and negligible degradation to the micro/nanostructure. The nanocomposite delivers a high capacity of 268 mAh g-1 at 0.2 C, which remains 126 mAh g-1 at 10 C for over 18 000 cycles. Coupling with a carbon-based cathode, a full cell of sodium-ion capacitor successfully demonstrates a high energy density of 64.2 Wh kg-1 at 56.3 W kg-1 and 25.8 Wh kg-1 at 1357 W kg-1, as well as an ultralong lifespan of 10 000 cycles with over 90% of capacity retention.

Evaluation of the electrochemical behavior and structural reversibility of Li3−xNaxV2(PO4)3/C (0≤x≤3) as anode materials for Na-ion batteries

A series of Li3−xNaxV2(PO4)3/C (0≤x≤3) materials are successfully prepared by a simple solid-state reaction method and used for the first time as anode materials for Na-ion batteries. Powder X-ray diffraction (XRD) results show that the phase structures of Li3−xNaxV2(PO4)3/C evolve along with the change of Li/Na atomic ratio (0≤x≤3). With increasing x in Li3−xNaxV2(PO4)3/C from 0.0 to 3.0, the main phase in as-prepared sample transforms from monoclinic Li3V2(PO4)3 to rhombohedral Li3V2(PO4)3, and finally to rhombohedral Na3V2(PO4)3, which results in different sodium storage behavior and performance between Li3−xNaxV2(PO4)3/C (0≤x≤3) materials. Electrochemical results show that Li3−xNaxV2(PO4)3/C (x=0.0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0) can deliver the initial charge capacities of 21.1, 35.9, 33.8, 41.7, 43.3, 43.9 and 47.7mAhg−1 at a current density of 10mAg−1, respectively. After 45 cycles, the reversible capacities can be kept at 16.9, 45.1, 32.6, 44.6, 43.7, 37.8 and 27.3mAhg−1 for Li3V2(PO4)3/C, Li2.5Na0.5V2(PO4)3/C, Li2NaV2(PO4)3/C, Li1.5Na1.5V2(PO4)3/C, LiNa2V2(PO4)3/C, Li0.5Na2.5V2(PO4)3/C and Na3V2(PO4)3/C, respectively. Furthermore, the structural reversibility of Li3−xNaxV2(PO4)3/C (x=1.0, 2.0, and 3.0) is also observed by in-situ XRD observation during sodiation/de-sodiation process. All these observed evidences indicate that only some of Li3−xNaxV2(PO4)3/C (0≤x≤3) can be used as possible sodium storage materials.

Synthesis and Electrochemical Properties of Fe<sub>2</sub>O<sub>3</sub>/rGO Nanocomposites as Lithium and Sodium Storage Materials

Synthesis and Electrochemical Properties of Fe<sub>2</sub>O<sub>3</sub>/rGO Nanocomposites as Lithium and Sodium Storage Materials

MnO2 nanotubes with a water soluble binder as high performance sodium storage materials

Well dispersed MnO2 nanotubes were synthesized via a hydrothermal method.

Gelatin-pyrolyzed mesoporous carbon as a high-performance sodium-storage material

Nitrogen-containing mesoporous carbons obtained by co-pyrolyzing gelatin and magnesium citrate at different temperatures show high reversible sodium storage capacity (up to 360 mA h g−1) and excellent cycling stability.

Enhanced Electrochemical Performance of Sb and Sb2O3 Composite By Electrodeposition for Na-Ion Batteries

Introduction As lithium reserves in natural resource cannot keep up with Li-ion battery market, concerns about a continuous supply of lithium and increasing of lithium price are emerging. Na-ion batteries are considered as an alternative to Li-ion batteries for large-scale applications due to the low-cost and abundance of sodium resources. While a variety of cathodes materials for Na-ion batteries have been reported [1], the availability of anode materials is much rarer. Among the candidates, Sb is very attractive anode materials for Na-ion battery due to high theoretical capacity (660 mAh/g).[2] Currently, sodium storage materials through conversion reaction mechanism have been reported, such as Sb2O4 [3], Sn-SnS-C[4], rGO/Sb2S3 [5], etc. These materials can give higher capacity because of the lower weight of the non-metal elements, as well as improvement of mechanical stability due to buffer matrix. Therefore, in this study, metallic antimony (Sb) and antimony trioxide (Sb2O3) composite were prepared by the electrodeposition from potassium antimony tartrate bath and electrochemical properties of Sb/Sb2O3 composite for Na-ion batteries are investigated. Additionally, the phase transition processes in sodium insertion/deinsertion of Sb/Sb2O3composite is investigated by ex-situ analysis. Experimental Sb/Sb2O3electrodes were prepared by the electrodeposition at a constant current density in a potassium antimony tartrate bath. The electrodeposition was conducted using a standard three-electrode cell; Cu foil was used as a cathode, pure Pt sheet was used as an anode, and a saturated calomel electrode (SCE) was used as a reference electrode. The solution was stirred magnetically at 240 rpm and the electrodeposition was performed at room temperature.The electrochemical properties of the Sb/Sb2O3 electrodes were investigated using two-electrode cell with electrode area of 1 cm2 assembled in an Ar-filled glove box. The cell consists of the Sb/Sb2O3 electrodes as a working electrode, a pure Na as a counter electrode and 1 M NaClO4 dissolved in a mixture of propylene carbonate (PC) and 0.5 vol. % of fluoroethylene carbonate (FEC) as an electrolyte. The electrochemical test was conducted by constant current with a current density of 60 mA/g in the potential range of 0.01 ~ 2.5 V vs. Na/Na+ at 25 oC. The phase transition with cycling was examined by ex-situ X-ray diffraction (XRD), and Raman spectroscopy. Results and discussion Figure 1.(a) shows the surface morphology of Sb/Sb2O3 composite prepared by the electrodeposition. Sb/Sb2O3 composite exhibits granular texture and deposited uniformly along the Cu substrate. Energy dispersive spectroscopy (EDS) analysis shows that the electrodeposits are composed of antimony and oxygen. Formation of crystalline Sb2O3 (cubic) as well as metallic Sb (rhombohedral) was confirmed by XRD analysis. Other impurity phases are not detected. (Figure 1. (b))The Sb/Sb2O3 electrode shows improved cycling stability rather than pure Sb electrode. The Sb/Sb2O3 electrode maintains a capacity of 613.2 mAh g-1 after 50 cycles that corresponds to 98.78 % of its initial charge capacity (620.8 mAh g-1) with a high coulombic efficiency above 95 %. In order to determine the reaction reversibility of Sb2O3 with Na+ ion, ex-situ XRD and Raman spectroscopy analysis with cycling were performed. It is confirmed that Sb2O3 reacts with Na+ ion reversibly by ex-situ analysis and reversible formation of Na2O by conversion reaction was expected. Accordingly, superior cycle stability of Sb/Sb2O3 composite results from Na2O which acts as buffer matrix and prevents agglomerating Sb particles. Figure 1 . (a) SEM images and (b) XRD patterns of Sb/Sb2O3composite References [1] M. D. Slater, D. Kim, E. Lee, C. S. Johnson, Advanced Functional Materials 2013, 23, 947.[2] J. Qian, Y. Chen, L. Wu, Y. Cao, X. Ai, H. Yang, Chemical Communications 2012, 48, 7070.[3] Q. Sun, Q. Q. Ren, H. Li, Z. W. Fu, Electrochemistry Communications 2011, 13, 1462.[4] L. Wu, X. Hu, J. Qian, F. Pei, F. Wu, R. Mao, X. Ai, H. Yang, Y. Cao, Journal of Materials Chemistry A 2013, 1, 7181.[5] D. Y. W. Yu, P. V. Prikhodchenko, C. W. Mason, S. K. Batabyal, J. Gun, S. Sladkevich, A. G. Medvedev, O. Lev, Nat Commun 2013, 4.

Na4Co3(PO4)2P2O7: A novel storage material for sodium-ion batteries

The electrochemical properties of Na4Co3(PO4)2P2O7 as a positive electrode for sodium-ion batteries were characterized by a cyclic voltammetry technique and galvanostatic charge/discharge tests. Interestingly, Na4Co3(PO4)2P2O7 has the multi redox couples in the highest potential region between 4.1 V and 4.7 V among ever reported sodium storage materials and can deliver the reversible capacity of ca. 95 mAhg−1, corresponding to ca. 2.2 Na+ extraction and insertion in Na4Co3(PO4)2P2O7, at the current density of 34 mAg−1 (0.2 C). Na4Co3(PO4)2P2O7 also exhibits the high rate capabilities and has a small polarization in the charge–discharge profile even at the high current densities of 4.25 Ag−1 (25 C), resulting in high energy efficiency of the battery. These performances indicate Na4Co3(PO4)2P2O7 can be one of the good candidates for a positive electrode material of sodium-ion batteries.