Development Of Sodium-ion Batteries Research Articles

Facilitating an Ultrastable O3-Type Cathode for 4.5 V Sodium-Ion Batteries via a Dual-Reductive Coupling Mechanism.

O3-type layered oxides for sodium-ion batteries (SIBs) have attracted extensive attention due to their inherently sufficient Na content, which have been considered as one of the most promising candidates for practical applications. However, influenced by the irreversible oxygen loss and the phase transition of O3-P3, the O3-type cathodes are always limited by low cutoff voltages (typically <4.2 V), restraining the full release of the capacity. In this study, we originally propose a dual-reductive coupling mechanism in a novel O3-type Na0.8Li0.2Fe0.2Ru0.6O2 cathode with the suppressed O3-P3 phase transition, aiming at improving the reversibility of oxygen redox at high voltage regions. Consequently, thanks to the formation of the strong covalent Fe/Ru-(O-O) bonding and inhibited slab gliding from the O to P phase, the cathode delivers the preeminent cyclic stability among the numerous O3-type cathodes within a high voltage of 4.5 V (a capacity retention of 95.4% after 100 cycles within 1.5-4.5 V). More importantly, HAADF-STEM and 7Li solid-state NMR results reveal the absence of transition metal migration and the presence of reversible Li migration during cycling, which further contributes to the improved structural robustness of the cathode. This study proposes an innovative strategy to boost the reversibility of anionic redox and to achieve stable high-voltage O3-type layered oxides, promoting the further development of SIBs.

Monolithic Interphase Enables Fast Kinetics for High-Performance Sodium-Ion Batteries at Subzero Temperature.

In spite of the competitive performance at room temperature, the development of sodium-ion batteries (SIBs) is still hindered by sluggish electrochemical reaction kinetics and unstable electrode/electrolyte interphase under subzero environments. Herein, a low-concentration electrolyte, consisting of 0.5M NaPF6 dissolving in diethylene glycol dimethyl ether solvent, is proposed for SIBs working at low temperature. Such an electrolyte generates a thin, amorphous, and homogeneous cathode/electrolyte interphase at low temperature. The interphase is monolithic and rich in organic components, reducing the limitation of Na+ migration through inorganic crystals, thereby facilitating the interfacial Na+ dynamics at low temperature. Furthermore, it effectively blocks the unfavorable side reactions between active materials and electrolytes, improving the structural stability. Consequently, Na0.7Li0.03Mg0.03Ni0.27Mn0.6Ti0.07O2//Na and hard carbon//Na cells deliver a high capacity retention of 90.8 % after 900 cycles at 1C, a capacity over 310 mAh g-1 under -30 °C, respectively, showing long-term cycling stability and great rate capability at low temperature.

Significant improvement in cycling and rate ability originating from regulation of bonding and transport channel via Ba2+ decoration in P2 layer oxide cathode

Nowadays, commercialization of layered transition metal oxides is hindered by irreversible phase transition during charging and discharging, low-capacity retention rate at high rate and slow Na+ diffusion kinetics. In this work, Ba2+ was introduced into the alkali metal layer to improve the electrochemical performance of layered transition metal oxides. XRD refinement and first principle calculations demonstrate that the introduced Ba2+ can effectively enlarge the distance between Na layers and reduce the potential barrier of sodium ion migration, thus leading to faster sodium ion diffusion kinetics. Simultaneously, charge distribution density calculation indicates that the introduced Ba2+ enhances overlap of electron clouds between transition metal (TM) and O, which result in more obvious covalence of TM-O bond, bigger electrostatic attraction between TM and O, and stronger bond energy of TM-O. These microstructures are beneficial to maintain structural stability and suppress the formation of OP4 phase during charging, which is demonstrated by XRD during charging and discharging process. The optimized Na0.6Ba0.012Mn0.62Ni0.22Fe0.16O2 provides reversible specific capacity of 133.8mAh g−1 at 0.5C (1C = 150mA g−1) and 122.1mAh g−1 at 2C. The strategy of regulating chemical bond environment by introducing Ba2+ achieves excellent the electrochemical performances and promotes the commercial development of sodium ion batteries.

Electrochemical Synthesis of Molybdenum Ditelluride (MoTe2) and Its Potential Application as Negative Electrode Material for Sodium Ion Battery

With the rapid expansion in energy demands and depletion of fossil fuel reservoirs, the importance of clean energy production and storage has increased drastically. The renewable energy recourses are cost effective, sustainable and carbon dioxide emission free alternatives. Nevertheless, this energy is not always available and needs to be stored. Lithium-ion batteries (LIBs) are rapidly used in various applications such as powering electronics, electric vehicles and grid energy storage. However, the source of lithium is extremely limited in earth crust, during mining it pollutes the environment and it is costly. Therefore, attention has been shifted towards development of sodium ion batteries (SIBs) which have wide reserves and low precursor cost and thus is considered as an appropriate choice for solar and wind energy development. The prime problem encountered in development of large-scale SIBs is the low effectiveness of appropriate anode material because of large size and sluggish kinetics of Na ions which limits the specific capacity as well as energy density.Metal tellurides have emerged as a promising material for use as negative electrode in sodium-ion batteries due to its unique layered crystal structure, high intrinsic conductivity, and high trap density. Molybdenum ditelluride has more electric conductivity than selenides and sulfides. Other metals except molybdenum in the group takes part in alloying mechanism that leads to higher volume expansion and poor cycling stability.In this study, we describe the synthesis of MoTe2 on copper and aluminium substrate by using predeposited molybdenum and electrodeposited tellurium at relatively low temperature of 450°C. Further we characterized the samples by X-Ray Diffraction, Raman Spectroscopy and Field Emission Scanning Electron Microscope for structural, elemental, and morphological properties, respectively. The synthesized material was used as negative electrode in sodium ion coin cell. The electrochemical performance of the coin cell will be correlated with the structural and electronic property of MoTe2.

Influences on Reliable Capacity Measurements of Hard Carbon in Highly Loaded Electrodes

AbstractFor the development of a full‐cell battery system, typically appropriate cathodes and anodes are characterized within a half‐cell setup where a metal counter electrode is installed to gather data about the employed electrodes. Ultimately, the individual capacity loadings allow for suitable balancing of the anode to cathode capacity in the full‐cell. This approach seems rather unproblematic for lithium‐ion batteries. For sodium‐ion batteries, however, we show that the high reactivity of sodium metal strongly influences hard carbon‐based electrode measurements within sodium‐ion half‐cells. As hard carbon is considered state‐of‐the‐art anode material, the presented results have high impact on the development of sodium ion batteries. Specifically, we show that the type of electrolyte, as well as cell‐ and measurement‐setup are key factors for reliable sodium half‐cell measurements of hard carbon. The investigated hard carbon electrodes have a high active material loading of 7.2 mg/cm2 (with 93 % active material content) resulting in an areal capacity of 2.4 mAh/cm2, which represent application‐relevant conditions.

Sb/SnO@C composite prepared by electrospinning for high performance sodium ion battery anodes

The development of high-performance anode material for sodium-ion batteries remains a challenge because of their low capacity, which limits their commercial application. Compared with carbon-based materials, metallic Sb and SnO-based anodes have received extensive attention because of their high theoretical specific capacity and safe working potential. The main problem faced is the serious volume expansion during charging and discharging, leading to irreversible loss of capacity and poor cycle life. In this paper, Sb/SnO@C composite material with adjustable ratio of Sb/SnO was prepared via electrospinning by encapsulating Sb and SnO particles in lantern-like carbon nanocages which connected through the nanofibers. The unique structure can not only effectively mitigate the volume changes during the cycle, but also provide multiple effective paths for ion and electron transport. The kinetic analysis is further performed with the assist of CV and EIS. The results show that the prepared composite can provide impressive Na+ ions storage and transport performance, and can still deliver a reversible charging capacity of 413mAhg−1 after 200 cycles at a current density of 50mAg−1, with a capacity retention ratio of 84%. This work provides a new strategy for the development of sodium ion batteries with high capacity and stable cycle performance.

Rational Design of Hollow Structural Materials for Sodium-Ion Battery Anodes.

The development of sodium-ion battery (SIB) anodes is still hindered by their rapid capacity decay and poor rate capabilities. Although there have been some new materials that can be used to fabricate stable anodes, SIBs are still far from wide applications. Strategies like nanostructure construction and material modification have been used to prepare more robust SIB anodes. Among all the design strategies, the hollow structure design is a promising method in the development of advanced anode materials. In the past decade, research efforts have been devoted to modifying the synthetic route, the type of templates, and the interior structure of hollow structures with high capacity and stability. A brief introduction is made to the main material systems and classifications of hollow structural materials first. Then different morphologies of hollow structural materials for SIB anodes from the latest reports are discussed, including nanoboxes, nanospheres, yolk shells, nanotubes, and other more complex shapes. The most used templates for the synthesis of hollow structrual materials are covered and the perspectives are highlighted at the end. This review offers a comprehensive discussion of the synthesis of hollow structural materials for SIB anodes, which could be potentially of use to research areas involving hollow materials design for batteries.

(Invited) Materials Development for Na-Ion Batteries and Insights from Operando Dilatometry and Gas Analysis (DEMS)

In the development of sodium ion batteries (SIBs), some classes of materials are showing particular promise. At the same time, there is a need to further improve these materials and, for example, reduce aging processes. In this presentation, the properties of various inorganic electrode materials for SIBs will be discussed. The focus is on carbon materials and carbon/Sn composites (anodes) as well as layered oxides and layered sulfides (cathodes). Operando dilatometry and DEMS (gas analysis) will be used to understand the behavior of the electrodes. By means of dilatometry, information is obtained about the "breathing" of the electrode during ion insertion and removal. Buffer defects caused by nanostructuring or overpotential metal plating can also be detected. DEMS can be used to determine the stability of different electrolyte solutions (ether vs. carbonates) and the cut-off potentials.

A closed-ended MXene armor on hollow Sn4P3 nanospheres for ultrahigh-rate and stable sodium storage

The development of sodium-ion batteries has been seriously discouraged by the major limitation in the rate capability and the cycle life of the anode materials. Sn4P3 is recognized as a potential anode for sodium -ion batteries owing to its ultrahigh specific capacity and low cost, but the great volumetric change and low intrinsic electrical conductivity severely limit the cycling performance. Herein, we propose a closed-ended MXene and Sn4P3 hybrid consisting of active Sn4P3 porous hollow nanospheres (Sn4P3 HS) armored by a conductive MXene shell. Notably, the outer MXene shell protects Sn4P3 from direct exposure to the electrolyte and only allows the inward expansion of Sn4P3 into the hollow space, resulting in the formation of a thin solid-electrolyte interphase layer of high stability. As predicted, the hybrids can deliver an extraordinarily high capacity of 302.1 mAh g−1 even at an ultrahigh rate of 10 A g−1 and cycle at 1 A g−1 for 1500 cycles with a capacity retention of 94.9%. Moreover, the Sn4P3 HS@MXene//Na3V2(PO4)3/C full cell exhibits an outstanding energy density of 287.8 Wh kg−1 and good cyclic ability (390.5 mAh g−1 at 1A g−1 after 500 cycles), exhibiting a great potential in practical application.

Surface engineered hollow Ni-Co-P@TiO2-x nanopolyhedrons as high performance anode material for sodium storage

With the proposal of carbon peaking and carbon neutrality goals, clean energy storage is attracting more and more attentions. In view of the lack of lithium resource in our earth, sodium-ion batteries are considered as the emerging and promising next-generation energy storage devices. Appropriate high-performance anode materials play a vital role in the development of sodium-ion batteries. Here, a core-shell hollow Ni-Co-P nanopolyhedron interconnected by oxygen defect TiO2 (Ni-Co-P@TiO2-x) is reported, which is synthesized by ion etching-hydrolysis and subsequent phosphatization/hydrogenation treatment using ZIF-67 as template and hybrid carbon source. The achieved Ni-Co-P@TiO2-x material has several distinct advantages including hollow core-shell structure, flexible conductive carbon matrix, stable electroactive coating layer, and efficient pseudocapacitive behavior, resulting in high reversible capacities, remarkable rate capability and excellent cycle stability. The synergetic battery-capacitor characteristic of Ni-Co-P@TiO2-x material makes it become a promising anode for sodium-ion batteries.

Amorphous 2D‐Nanoplatelets of Red Phosphorus Obtained by Liquid‐Phase Exfoliation Yield High Areal Capacity Na‐Ion Battery Anodes

AbstractThe development of sodium ion batteries will require high‐performance electrodes with very large areal capacity and reasonable rate performance. Although red phosphorus is a very promising electrode material, it has not yet fulfilled these requirements. Here, liquid phase exfoliation is used to convert solid red phosphorus into amorphous, quasi‐2D nanoplatelets. These nanoplatelets have lateral sizes of hundreds of nanometers, thickness of 10s of nanometers and are quite stable in ambient conditions, displaying only low levels of oxidation on the nanosheet surface. By solution mixing with carbon nanotubes, these nanoplatelets can be fabricated into nanocomposite battery anodes. After employing an extended activation process, good cycling stability over 1000 cycles and low‐rate capacitances &gt;2000 mAh gP−1 is achieved. Because of the high conductivity and mechanical robustness provided by the nanotube network, it is possible to fabricate very thick electrodes. These electrodes display extremely high areal capacities approaching 10 mAh cm−2 at currents of ≈1 mA cm−2. Detailed analysis shows these electrodes to be limited by solid‐state diffusion such that the thickest electrodes have state‐of‐the‐art rate performance and a near‐optimized combination of capacity and rate performance.

Interface and electronic structure dual-engineering on MoSe2 with multi-ion/electron transportation channels for boosted sodium-ion half/full batteries

It is of great significance to design and prepare high performance anode materials for the development of sodium ion batteries (SIBs). In this work, the innovative approach of interface and electronic structure dual-engineering is applied on MoSe2 to fabricate novel C/N co-doped bilayer hollow structured MoSe2 nanosheets (BH-MoSe2@CNBs). With the comparison of traditional MoSe2/C composite, the sandwich structured MoSe2 with double carbon coating can bring multi-ion/electron transportation channels, favoring the Na+ storage and charge transfer kinetics. Specifically, the inner carbon shell as a supporting skeleton not only restrains the agglomeration of lamellar MoSe2, but also buffers the stress of sodium ions (de)insertion. The outer carbon layer plays a crucial role in adsorbing the polyselenide intermediates, maintaining the stability and reversible capacity of the middle MoSe2 electrode. As anode for SIBs, BH-MoSe2@CNBs exhibit 347 mAh g−1 at 10 A g−1 after 1300 cycles, which is comparable with the previously reported MoSe2-based electrode in SIBs. Additionally, the BH-MoSe2@CNBs//Na3V2(PO4)2O2F full cell can reach an energy density of 107.4 Wh kg−1 at a power density of 3832 W kg−1, indicating the potential practical application. The theoretical calculation is also conducted to confirm the superior Na+ adsorption of BH-MoSe2@CNBs. The interface and electronic structure dual-engineering on MoSe2 can provide innovative points for the exploitation of efficient anode materials for SIBs.

Ultrathin 2D hexagon CoP/N-doped carbon nanosheets for robust sodium storage

Due to the natural abundance and potential price advantage, sodium-ion batteries (SIBs) have attracted increasing attention as promising alternatives to lithium-ion batteries (LIBs). However, the development of SIBs is severely hampered due to the poor cycling stability and low rate capability resulting from the larger ionic size of Na+ than that of Li+. Herein, 2D hexagon CoP/N-doped carbon (H-CoP@NC) nanosheets have been prepared via solvothermal method combined with the upper gas phase phosphating. Benefiting from the synergistic effect of N-doped carbon layer and ultrathin 2D hexagonal nanosheet structure, the H-CoP@NC as anode materials exhibit superior electrochemical performances in terms of rate capability and cyclic stability, delivering specific capacity of 209.9 mAhg−1 at 2 Ag−1 after 1100 cycles for SIBs, and high Coulombic effciency of approximately 100% over 1100 cycles. Ex-situ XRD were performed to research the structural evolution between Na and CoP during cycling processes. Analysis from the Ex-situ XPS and work function indicates that the enhanced electrochemical property H-CoP@NC might be attributed to the stable SEI film, lower charge-transfer resistance and better electrode kinetics as a result of thinner nanosheet and the presence of carbon layer.

Hard carbon derived for lignin with robust and low-potential sodium ion storage

Hard carbon as the anode materials is the key for the development of sodium ion batteries (SIBs). However, low initial Coulomb efficiency (ICE) and specific capacity still hinder the development of hard carbon materials. Herein, hard carbon materials derived from lignin were prepared by controlling carbonization temperature, and the resulting hard carbon were used in SIBs. The storage mechanism of SIBs was discussed. In addition, the effect of carbonization temperature on the structure and chemical performance of hard carbon was investigated. As a result of its optimized microstructure, such as lower specific surface area, larger space of the interlayers and fewer defects, hard carbon from lignin carbonized at 1600 ℃ (LDHC-1600) exhibits ICE of 81.2 %, and reversible discharge capacity of 303 mA h g−1, and the ratio of low potential plateau to total capacity is 74.75 % (226.5 mA h g−1). The mechanism revealed that sodium ions are adsorbed in the slope region and the intercalation and filling mechanism in the plateau region are also verified. This study provides a type of biomass carbon anode material from lignin for application of SIBs.

Insights into Synergistic Effect of g-C3N4/Graphite Heterostructures for Boosting Sodium Ion Storage with Long Cycle Stability

Sodium-ion batteries (SIBs) have attracted significant attention as promising next-generation energy storage devices. However, the research and development of SIBs are still in their infancy due to the lack of suitable high-performance anode materials. As a commercial anode material for lithium-ion batteries (LIBs), graphite often shows a low sodium storage capacity. Herein, a graphite heterojunction material was prepared through a facile ball-milling method. During the ball-milling process, a defect-enriched g-C3N4/graphite heterojunction was formed and the nitrogen-containing functional groups were regulated, which promoted the sodium storage capacity. The resulting g-C3N4/graphite electrode can exhibit excellent long cycle stability and rate performance, delivering a high reversible capacity of 202 mAh g–1 at 1.0 A g–1 after 6000 cycles and 90.06 mAh g–1 at 5.0 A g–1 after 10000 cycles. Moreover, an ultrahigh rate capability can also be obtained at 1.0 A g–1 with a capacity of 111 mAh g–1. The superiority of heterostructures for sodium storage and diffusion was proved via DFT calculations, which verified the synergistic effect between graphite and g-C3N4. This study provides a simple and efficient method for preparing g-C3N4/graphite heterostructures as well as a deep insight into the sodium storage mechanism of a heterostructure anode.

Constructing N-Doped graphene supported MoS2@Ni3S4 for pseudocapacitive sodium-ion storage with high rate and long life

The development of sodium-ion batteries with a high-power density and long life has attracted considerable interest because of their low cost and potential applications. In this work, we constructed N-doped graphene supported pseudocapacitive material consisting of Ni3S4 grains (50 nm) coated by 3–4 layers of MoS2 (MoS2@Ni3S4/NG) by facile one-step pyrolysis of nickel phthalocyanine. When the electrode was used as an anode for sodium-ion batteries, a pseudocapacitance-dominated storage mechanism was established, and the extrinsic pseudocapacitance could be further enhanced with the structural evolution of MoS2@Ni3S4 during the sodiation/desodiation process, contributing to fast kinetics of Na+ storage. The results of impedance analysis indicated that the MoS2 layers play a vital role in reducing the charge-transfer resistance because the MoS2 with wider interlayer spacing enables Na+ to intercalate with a lower energy barrier compared with intercalating into Ni3S4 directly. As a result, the electrode exhibits a superior cycle life over 1000 cycles, and an excellent rate capacity of 564 mAh g−1 can be achieved at 0.5 A g−1.

层状钒酸钾应用于高性能高温钠离子电池

The high-temperature sodium-ion batteries (SIBs) used for large-scale energy storage have attracted extensive attention in recent years. However, the development of SIBs is still hampered mainly by their poor charge/discharge efficiency and stability, necessitating the search for appropriate electrodes. A simple potassium ion intercalation process is used herein to obtain the potassium vanadate (KV3O8) nanobelts. When serving as the anode for SIBs at a high temperature (60°C), the KV3O8 nanobelts display superior sodium storage performance with a high capacity of 414 mA h g−1 at 0.1 A g−1, remarkable rate capability (220 mA h g−1 at 20 A g−1), and super-long cycle life (almost no capacity fading at 10 A g−1 over 1000 cycles). Moreover, the ex-situ X-ray powder diffraction reveals no structural changes throughout the whole charge/discharge process, which further confirms their outstanding stability, indicating KV3O8 nanobelts are a promising candidate for high-temperature SIBs.

A Lignosulfonate Binder for Hard Carbon Anodes in Sodium-Ion Batteries: A Comparative Study

An important factor in the development of sodium-ion batteries (SIBs) is the use of cheap and sustainable materials. Sodium lignosulfonate, a lignin derivative, is demonstrated here as an attractive, “green”, water-soluble, and potentially cost-effective binder for use in hard carbon anodes for SIBs. A comparison of its battery cycling performance is made against other binders including sodium carboxymethyl cellulose and lignin, obtained from the kraft process, as well as sodium alginate, derived from algae. Apart from lignin, which requires processing in N-methyl-2-pyrrolidone, the other three binders are water-soluble. Lignosulfonate shows comparable or better performance, with high capacity retention and stability, when using 1 M NaPF6 in propylene carbonate or ethylene carbonate:diethyl carbonate electrolytes for both half- and full-cells (against a Prussian white cathode). Further improvements are observed when including styrene-butadiene rubber as a co-binder. X-ray photoelectron spectroscopy demonstrates similar solid electrolyte interphase compositions after the initial sodium insertion for both lignosulfonate and carboxymethyl cellulose binders. However, after subsequent cycling, the surface layer composition and thickness are found to be dependent on the binder. For the lignosulfonate-based electrode, the layer appears thicker but comprises a smaller fraction of carbon–oxygen species.

Cycling degradation and safety issues in sodium-ion batteries: Promises of electrolyte additives

Sodium-ion batteries (SIBs) have drawn particular attention in recent years as a promising alternative to lithium-ion batteries (LIBs) due to the advantages of sodium (Na) metal. Like LIBs, SIBs suffer from deterioration of cycling performance due to reactions occurring at the electrode-electrolyte interfaces. Moreover, they encounter safety issues arising from conventional organic electrolytes' flammability and the abuse of battery under overcharge conditions. Adding a small dose of additives into the electrolyte of SIBs can positively mitigate the abovementioned problems. In addition to categorizing the electrolyte additives used in SIBs, the recently published research and results on applying electrolyte additives in SIBs are comprehensively evaluated in this review paper. The challenges associated with the development of SIBs in terms of their electrolyte and the practical suggestion for exploring new electrolyte additives special to SIBs are thoroughly discussed.

Self-Template Synthesis of Prussian Blue Analogue Hollow Polyhedrons as Superior Sodium Storage Cathodes

Prussian blue and its analogues with three-dimensional frame structures have been shown to be of great importance in the research and development of sodium-ion batteries (SIBs). Herein, we develop a simple and convenient self-template method to prepare a hollow-structured Prussian blue analogue (CoFe-PBA). This structure is conducive to buffer the volume changes during ion extraction and insertion processes and shorten the ion diffusion path. When further building a thin polydopamine (PDA) coating, the synthesized CoFe-PBA@PDA exhibits a high discharge capacity of 123.1 mAh g-1 at 0.1 A g-1 with a capacity retention of 71.5% after 500 cycles. Moreover, the capacity retention of CoFe-PBA@PDA after 100 cycles is 14.3% higher than that of the two comparison samples. In addition, the reversible structure of CoFe-PBA@PDA without forming a new phase was verified by in situ X-ray diffraction. This work may provide another design idea or strategy for improving the stability of the PBA cathodes used in SIBs.