Subzero-Temperature Cathode for a Sodium-Ion Battery.

Monolithic Hierarchical Carbon Assemblies Embedded with Mesoporous NaTi2(PO4)3 Nanocrystals for Flexible High-Performance Sodium Anodes

Assessment of the first commercial Prussian blue based sodium-ion battery

Numerous efforts have been devoted to developing high-performance graphene-based electrodes for application in advanced electrochemical energy storage systems (e.g., lithium ion batteries (LIBs) and sodium ion batteries (SIBs)), including modified graphene with various structures and types of heteroatom doping, as well as their related composite-/hybridized-electrode materials. Owing to their outstanding characteristics (large surface area, high electronic conductivity, high charge carrier mobility, great mechanical strength, and high theoretical capacity), graphene-based electrodes have been widely demonstrated to show improved and diverse properties for LIBs and SIBs in terms of high specific capacity, high rate capability, long cycling life, and flexible-battery structures. In this chapter, we briefly provide an overview of the significant progress achieved on graphene-based electrodes (including both cathodes and anodes) for application in LIBs and SIBs over the past decade. Moreover, despite the impressive improved electrochemical performance reported for LIBs and SIBs, emerging challenges and some perspectives on the use of graphene-based electrodes for future LIB and SIB applications are also presented in this chapter.

Recently ambient temperature sodium-ion batteries have drawn great attention particularly in large-scale electric energy storage applications for renewable energy and smart grid due to the low cost and abundant sodium resources. Up to now, lots of cathode and anode materials as well as electrolytes have been proposed for Na-ion batteries. However, little research about the safety issue of Na-ion batteries has been carried out. It is well known that Li-ion batteries have thermal risk under abuse or severe environment. Because Na-ion batteries have similar working mechanism as Li-ion batteries and sodium shows even higher reactivity against air, the study on thermal stability of Na-ion batteries is indispensable for its practical application.Iron oxyfluoride (FeOF) is a kind of iron based conversion type cathode material, which had been proposed as a cathode material for Li-ion batteries and obtained a large practical capacity due to conversion reactions [1, 2]. In this study, FeOF was also applied as the cathode material for Na-ion batteries. After electrochemical pretreatment in Na-ion or Li-ion batteries, the charged/discharged FeOF cathodes were mixed with corresponding electrolytes and thermally analyzed. By varying the ratio of cathode/electrolyte in the mixture, the heat generation mechanisms of FeOF cathodes in Na-ion and Li-ion batteries were discussed, and the thermal stability of Na-ion and Li-ion batteries were compared.FeOF was synthesized by a reaction of 1:2.33 molar ratio of Fe2O3 (Sigma-Aldrich) and FeF3 (Soekawa Chemicals Co., Ltd.) at a temperature over 1000 oC in a roll-quenching machine (Harddays Co. Ltd). The synthesized FeOF had been indexed as a tetragonal structure with P42/mnm space group. The obtained FeOF flake was ground with acetylene black using a planetary ball milling machine at a weight ratio of 70:25. 5 wt.% PVdF and polyacrylate binders were added in the cathodes for Li-ion batteries and Na-ion batteries, respectively. The electrochemical measurements were carried out with 2032 coin-type two-electrode cells. In Li-ion batteries, Li foil was used as a counter electrode and 1 mol/cm3 LiPF6/EC-DMC or 1 mol/cm3 LiClO4/PC as an electrolyte. In Na-ion batteries, Na foil was used as a counter electrode and 1 mol/cm3 NaClO4/PC as an electrolyte. The cells were cycled at constant current densities of 10 mA/g (0.02 mA/cm2). For thermal analysis, the cycled cathodes were taken out from the disassembled cells, soaked in PC or DMC, rinsed by DMC, and then vacuum dried. Finally, the cathode powder was packed into a stainless-steel pan together with some amount of corresponding electrolyte. During TG-DSC analysis, the hermetically sealed pan was heat up to 500 oC with a heating rate of 5 oC/min.Figure 1 shows the DSC curves of the mixtures of given amount of lithiated or sodiated FeOF cathode and 1 μl corresponding PC-based electrolytes. In both Li- and Na-ions batteries, charged FeOF cathodes showed large exothermic heat with an onset temperature of about 100 oC. This was attributed to reactions between expanded FeOF at the charged state and the electrolyte. Moreover, intercalated Na ions were found to induce an exothermic heat peaked at about 450 oC, while this peak was not observed in Li-ion batteries. Detailed discussion will be presented at the conference.

Cubic Prussian blue crystals from a facile one-step synthesis as positive electrode material for superior potassium-ion capacitors

High capacitive sodium-ion storage in N, P co-doped carbon supported on carbon nanotubes

Energy storage systems made from abundant materials are essential for the transition to a more sustainable economy. Although today lithium-ion batteries (LIBs) are the most popular battery technology, the growing demand and low availability of lithium, as well as the use of cobalt and other rare metals raise questions about the sustainability and long-term viability of LIB as the only energy storage solution. The high abundance of sodium content and relative similarity to LIBs, allows the sodium ion batteries (SIBs) to be considered as alternative for stationary energy storage [1]. However, the widespread adoption of SIB technology is hampered by many challenges, including the relatively low energy density compared to LIB. Lower energy density electrodes, such as Na2FeP2O7, are generally stable during cycling [2], while many higher energy density electrodes, such as NaxMnO2, have had a shorter cycle life [3]. In this work we show several possible solutions how to improve the electrochemical properties of the SIBs made of these cathode materials.The promising cathode material Na2FeP2O7 was studied to improve its electrical conductivity, which is often low in the case of sodium pyrophosphates. Solution synthesis was used to prepare pristine Na2FeP2O7 and Na2FeP2O7/C composite cathode materials for sodium-ion batteries, using glucose as a carbon source. While the pristine Na2FeP2O7 displays capacity of only 45 mAh/g due to the relatively large grain size, the addition of carbon increases the capacity to up to 92 mAh/g (95% of the theoretical 97 mAh/g capacity) with excellent rate capability, as 44 mAh/g capacity is still retained even at 20 C (1.94 A/g) current. The optimal content of carbon was found to be 4.8%. The initial capacity of 81 mAh/g is fully retained after 500 cycles at 1 C, indicating excellent cycle life of Na2FeP2O7/C. Electrochemical measurements were carried out in 1 M NaClO4 salt in propylene carbonate as electrolyte and show that the addition of 5 wt.% fluoroethylene carbonate solid electrolyte interphase stabilizing additive greatly benefits the rate and cycling performance of Na2FeP2O7/C as measured in half-cells [4].Na0,67MnO2 is another compound that is widely studied as cathode materials in sodium ion batteries. Currently polyvinylidene fluoride (PVDF) is the most popular binder choice. In our study, a novel tetrabutylammonium (TBA) alginate binder is used to prepare a Na0,67MnO2 electrode for sodium-ion batteries with improved electrochemical performance. The ageing of the electrodes has been characterized. TBA alginate-based electrodes are compared to PVDF and Na alginate-based electrodes and show favorable electrochemical performance, with gravimetric capacity values of up to 164 mAh/g, which is 6% higher than measured for the electrode prepared with PVDF binder. TBA alginate-based Na0,67MnO2 electrodes also display good rate capability and improved cyclability and their solid–electrolyte interface is similar to that of PVDF-based electrodes. As the only salt of alginic acid soluble in non-aqueous solvents, TBA alginate emerges as a good alternative to PVDF binder in battery applications where the water-based processing of electrode slurries is not feasible, such as the demonstrated case with Na0,67MnO2 [5].Overall, we have shown that binder and electrolyte selection can significantly improve the electrochemical properties of electrode materials for SIBs.The financial support of projects No. 1.1.1.2/VIAA/1/16/166 “Advanced materials for sodium Ion batteries” and No. lzp-2020/1-0391 “Advanced polymer – ionic liquid composites for sodium-ion polymer batteries” is greatly acknowledged. Institute of Solid-State Physics, University of Latvia as the Center of Excellence has received funding from the European Union's Horizon 2020 Framework Program H2020-WIDESPREAD-01–2016-2017-Teaming Phase 2 under grant agreement No. 739508, project CAMART2. Vaalma, C.; Buchholz, D.; Weil, M.; Passerini, S. A cost and resource analysis of sodium-ion batteries. Nat. Rev. Mater. 2018, 3, 18013.Jin, T.; Li, H.; Zhu, K.; Wang, P.-F.; Liu, P.; Jiao, L. Polyanion-type cathode materials for sodium-ion batteries. Chem. Soc. Rev. 2020, 49, 2342.Lyu, Y.; Liu, Y.; Yu, Z.-E.; Su, N.; Liu, Y.; Li, W.; Li, Q.; Guo, B.; Liu, B. Recent advances in high energy-density cathode materials for sodium-ion batteries. Sustain. Mater. Technol. 2019, 21, e00098.Kucinskis, G.; Nesterova, I.; Sarakovskis, A.; Bikse, L.; Hodakovska, J.; Bajars, G. Electrochemical performance of Na2FeP2O7/C cathode for sodium-ion batteries in electrolyte with fluoroethylene carbonate additive. J. Alloys Compd. 2022, 895, 162656.Kucinskis, G.; Kruze, B.; Korde, P.; Sarakovskis, A.; Viksna, A.; Hodakovska, J.; Bajars, G. Enhanced Electrochemical Properties of Na67MnO2 Cathode for Na-Ion Batteries Prepared with Novel Tetrabutylammonium Alginate Binder. Batteries 2022, 8, 6. Figure 1

It is desirable to develop alternative electrochemical devices with comparable performance but lower cost to substitute for lithium-ion batteries. Sodium-ion batteries show very similar electrochemical mechanism to lithium-ion batteries. The abundant sodium resource can considerably reduce the cost of energy storage devices as compared with lithium-ion batteries. In this work, a new derivative of sodium iron sulfates, Na6Fe5(SO4)8 (NFS), is developed as cathode material for sodium-ion batteries. The NFS is synthesized from sodium carbonate, sodium sulfate and iron sulfate raw materials, and it shows a high working voltage of 3.7 V vs. Na+/Na. When combined with carbon nanotube (CNT), the NSF@CNT composite demonstrates increased electronic conductivity and superior electrochemical performance. A 3.6 V sodium-ion full battery is constructed based on NFS@CNT cathode and hard carbon (HC) anode materials. Such a full NFS@CNT//HC cell can deliver an energy density towards 350 Wh kg-1 and cycling stability over prolonged 1000 cycles at 2 C. This work offers a low-cost sodium-ion full battery with an impressive high working voltage and energy/power densities for possible stationary energy storage applications.

Sodium-ion batteries have attracted considerable attention in recent years. In order to promote the practical application of sodium-ion batteries, the electrochemical performances, such as specific capacity, reversibility, and rate capability of the anode materials, should be further improved. In this work, a Fe2O3/C composite with a well-ordered mesoporous structure is prepared via a facile co-impregnation method by using mesoporous silica SBA-15 as a hard template. When used as an anode material for sodium-ion batteries, the well-ordered mesoporous structure ensures fast mass transport kinetics. The presence of nano-sized Fe2O3 particles confined within the carbon walls significantly enhances the specific capacity of the composite. The carbon walls in the composite act not only as an active material contributing to the specific capacity, but also as a conductive matrix improving the cycling stability of Fe2O3 nanoparticles. As a result, the well-ordered mesoporous Fe2O3/C composite exhibits high specific capacity, excellent cycleability, and high rate capability. It is proposed that this simple co-impregnation method is applicable for the preparation of well-ordered mesoporous transition oxide/carbon composite electrode materials for high performance sodium-ion and lithium-ion batteries.

Antimony oxychloride/graphene aerogel composite as anode material for sodium and lithium ion batteries

With the tremendous development of renewable energies such as solar and wind powers, the smooth integration of their energies into the grid, thus improving the grid reliability and utilization, critically needs large-scale energy storage systems with long-life, high efficiency, high safety and low cost. Among the various energy storage technologies, electrochemical approach represents one of the most promising means to store the electricity in large-scale because of the flexibility, high energy conversion efficiency and simple maintenance. Due to the highest energy density among practical rechargeable batteries, lithium-ion batteries have been widely used in the portable electronic devices and would undoubtedly be the best choice for the electric vehicles. However, the rarity and non-uniform distribution of lithium in the Earth’s crust (0.0065%) may limit their large scale application in renewable energy. In this regard, room-temperature sodium-ion batteries with lower energy density compared with lithium-ion batteries have been reconsidered particularly for such large-scale applications, where cycle life and cost are more essential factors than energy density owing to the abundant sodium resources (2.75%) and potentially low cost as well as similar “rocking-chair” sodium storage mechanism as lithium1-11. Searching for suitable electrode materials to satisfy the long-term stability requirement is an important step to realize the large-scale energy storage. Recently, many layered Na x MO2 (M: 3d transition metals) oxides have been proposed as positive electrode materials for sodium-ion batteries. Amongst them, in general, only layered oxides containing Ni or Co transition metal show promising Na storage performance in terms of high storage capacity, high rate capability and long cycling stability. However, Ni and Co are toxic and their oxides are relatively expensive, which would certainly increase the cost of the battery and is unfavorable for large-scale energy storage applications. Herein, we found that Cu2+/Cu3+ redox couple in such layered oxides is electrochemically active and highly reversible in sodium-ion batteries12. Take P2-Na0.68Cu0.34Mn0.66O2 as the first example, this material shows a reversible capacity of ca. 70 mAh/g with an average storage voltage of 3.8 V vs. Na+/Na. To the best of our knowledge, this is the first time to realize the reversible change of Cu2+/Cu3+ redox couple with high Na storage voltage and small polarization. Copper is harmless, and is already very common in our daily life. In addition, the cost of copper oxide is only half of that of nickel oxide. Based on this important finding, it is possible to use copper to design new layered oxides with similar Na storage performance as that of Ni or Co containing layered oxides. Therefore, we further optimize a series of air-stable NaaDxMnyFezCu1-x-y-zO2 (D(Dopant): Mg, Al, etc.) layered oxides13,14. The preliminary results are very promising and will be presented in this talk (Figure 1).

Sodium-ion batteries (SIBs) receive significant attention for electrochemical energy storage and conversion owing to their wide availability and the low cost of Na resources. However, SIBs face challenges of low specific energy, short cycling life, and insufficient specific power, owing to the heavy mass and large radius of Na(+) ions. As an important component of SIBs, cathode materials have a significant effect on the SIB electrochemical performance. The most recent advances and prospects of inorganic and organic cathode materials are summarized here. Among current cathode materials, layered transition-metal oxides achieve high specific energies around 600 mW h g(-1) owing to their high specific capacities of 180-220 mA h g(-1) and their moderate operating potentials of 2.7-3.2 V (vs Na(+) /Na). Porous Na3 V2 (PO4 )3 /C nanomaterials exhibit excellent cycling performance with almost 100% retention over 1000 cycles owing to their robust structural framework. Recent emerging cathode materials, such as amorphous NaFePO4 and pteridine derivatives show interesting electrochemical properties and attractive prospects for application in SIBs. Future work should focus on strategies to enhance the overall performance of cathode materials in terms of specific energy, cycling life, and rate capability with cationic doping, anionic substitution, morphology fabrication, and electrolyte matching.

Review: 218 refs.

Sodium-ion batteries (SIBs) have emerged as a promising alternative to lithium-ion batteries (LIBs) due to the abundant availability and low cost of sodium. Recent advances in SIB technology have focused on enhancing the performance, safety, and cost-effectiveness of these batteries. Significant progress has been made in the development of high-capacity anode and cathode materials, including hard carbon, sodium titanium phosphate, layered transition metal oxides, and polyanionic compounds. Innovations in electrolyte composition and the design of advanced binders and separators have further improved the stability and efficiency of SIBs. Efforts to understand and mitigate the challenges associated with the larger ionic radius of sodium compared to lithium have led to better cycle life and higher energy densities. Additionally, research into solid-state electrolytes and novel cell architectures is pushing the boundaries of SIB performance. Despite these advancements, challenges such as lower energy density and shorter cycle life compared to LIBs remain. Nevertheless, ongoing research and development are expected to address these issues, positioning SIBs as a viable option for large-scale energy storage applications, including grid storage and electric vehicles. This review highlights the recent progress in SIB technology and discusses the future directions and potential of SIBs in the energy storage landscape.

Tin oxide (SnO2) is considered as a promising material for both Li- and Na-ion batteries due to its high theoretical capacities (1494 mAh/g with Li and 1378 mAh/g with Na; 2~3 times higher than common carbon-based anode)1-3. However, the initial irreversible capacity loss induced by inactive Li2O/Na2O formation and volume change (260% with Li and 420% with Na) during charge/discharge process need to be addressed in order to improve cycling performance4. In addition, the poor electronic conductivity of above mentioned alkali metal oxides and gradual aggregation of Sn particles in the electrode structure during operation lead to poor rate capability and rapid capacity fading. Many studies have strived to address these issues and result in the development of diverse types of SnO2-based nanocomposites with carbonaceous materials including reduced graphene oxides5-7, carbon nanofibers8,9, carbon nanotubes10,11, and disordered carbons12,13 to enhance initial coulombic efficiency and electronic conductivity in the electrode structure as well as to prohibit Sn particle aggregation by introducing physical barriers between active materials. However, the cycling performance and initial irreversible capacity loss of the currently reported composites still remain insufficient to be adopted in practical cells. In this work, carbon-coated porous Sn/SnO2 composite (Sn/SnO2@C) is synthesized via inorganic CO2 reduction route with magnesium stannide (Mg2Sn) for Li- and Na-ion batteries. High purity Mg2Sn powder is prepared by solid-state reaction and then thermally treated under CO2 flow environment. During the second heat treatment, gaseous CO2 molecules becomes reduced down to elemental C via interaction with Mg which is known to be highly reductive in nature (Mg2Sn + CO2 à 2MgO + Sn + C, ΔG = -690 kJ/mol). The resultant Sn is partially oxidized to form SnO2 which eventually results in Sn/SnO2@C composite. Electrodes with this composition and structure exhibit enhanced initial coulombic efficiency and stable cycling performance. It appears that a nanocomposite matrix in which active materials are distributed without aggregation in intimate contact with C is essential for realizing SnO2-based anodes for Li- and Na-ion batteries with long cycle life. 1 Lee, J.-I. et al. Multifunctional SnO2/3D graphene hybrid materials for sodium-ion and lithium-ion batteries with excellent rate capability and long cycle life. Nano Research, doi:10.1007/s12274-017-1756-3 (2017). 2 Kim, Y., Yoon, Y. & Shin, D. Fabrication of Sn/SnO2 composite powder for anode of lithium ion battery by aerosol flame deposition. Journal of Analytical and Applied Pyrolysis 85, 557-560, doi:https://doi.org/10.1016/j.jaap.2008.06.005 (2009). 3 Lee, Y. et al. Hollow Sn–SnO2 Nanocrystal/Graphite Composites and Their Lithium Storage Properties. ACS Applied Materials & Interfaces 4, 3459-3464, doi:10.1021/am3005237 (2012). 4 Sivashanmugam, A. et al. Electrochemical behavior of Sn/SnO2 mixtures for use as anode in lithium rechargeable batteries. Journal of Power Sources 144, 197-203, doi:https://doi.org/10.1016/j.jpowsour.2004.12.047 (2005). 5 Hu, X., Zeng, G., Chen, J., Lu, C. & Wen, Z. 3D graphene network encapsulating SnO2 hollow spheres as a high-performance anode material for lithium-ion batteries. Journal of Materials Chemistry A 5, 4535-4542, doi:10.1039/C6TA10301D (2017). 6 Fan, L. et al. Controlled SnO2 Crystallinity Effectively Dominating Sodium Storage Performance. Advanced Energy Materials 6, 1502057-n/a, doi:10.1002/aenm.201502057 (2016). 7 Tian, R. et al. The effect of annealing on a 3D SnO2/graphene foam as an advanced lithium-ion battery anode. Scientific Reports 6, 19195, doi:10.1038/srep19195 https://www.nature.com/articles/srep19195#supplementary-information (2016). 8 Wang, M., Li, S., Zhang, Y. & Huang, J. Hierarchical SnO2/Carbon Nanofibrous Composite Derived from Cellulose Substance as Anode Material for Lithium-Ion Batteries. Chemistry – A European Journal 21, 16195-16202, doi:10.1002/chem.201502833 (2015). 9 Liu, Y. et al. Enhanced electrochemical performance of hybrid SnO2@MOx (M = Ni, Co, Mn) core-shell nanostructures grown on flexible carbon fibers as the supercapacitor electrode materials. Journal of Materials Chemistry A 3, 3676-3682, doi:10.1039/C4TA06339B (2015). 10 Cui, J. et al. Enhanced conversion reaction kinetics in low crystallinity SnO2/CNT anodes for Na-ion batteries. Journal of Materials Chemistry A 4, 10964-10973, doi:10.1039/C6TA03541H (2016). 11 Chen, S. et al. Branched CNT@SnO2 nanorods@carbon hierarchical heterostructures for lithium ion batteries with high reversibility and rate capability. Journal of Materials Chemistry A 2, 15582-15589, doi:10.1039/C4TA03218G (2014). 12 Fan, J. et al. Ordered, Nanostructured Tin-Based Oxides/Carbon Composite as the Negative-Electrode Material for Lithium-Ion Batteries. Advanced Materials 16, 1432-1436, doi:10.1002/adma.200400106 (2004). 13 Pol, V. G., Wen, J., Miller, D. J. & Thackeray, M. M. Sonochemical Deposition of Sn, SnO2 and Sb on Spherical Hard Carbon Electrodes for Li-Ion Batteries. Journal of The Electrochemical Society 161, A777-A782, doi:10.1149/2.064405jes (2014).