Figure - available from: Scientific Reports
This content is subject to copyright. Terms and conditions apply.
Superoxide stability. (a) Interaction between oxygen species (oxide, peroxide or superoxide) and cationic species (bare cations, solvated cations and solvated anion-coordinated cations). The solvation number is not limited to four as shown. Indirect anion coordination where solvent molecules bridge anion and cation is possible even if the direct coordination softens the Lewis acidity of cations more effectively. Bidirectional arrows indicates the interaction between acids and bases: O on the arrows for strong interaction; X for weak or no interaction. (b) Contour plots of the standard rate constants (ko) of superoxide formation on 2D DN map for superoxide stability. Gutmann’s DN and Linert’s DN values were used for solvents and anions, respectively. The symbols and numbers indicating experimental data points are explained in detail in the text body.
Source publication
Stabilizing superoxide (O2-) is one of the key issues of sodium-air batteries because the superoxide-based discharge product (NaO2) is more reversibly oxidized to oxygen when compared with peroxide (O22-) and oxide (O2-). Reversibly outstanding performances of sodium-oxygen batteries have been realized with the superoxide discharge product (NaO2) e...
Similar publications
The isonitrile (NC) group has been shown to be a promising infrared probe for studying the structure and dynamics of biomolecules. However, there have been no systematic studies performed on the NC group as an infrared probe, when it is bonded to an indole ring. Here, we systematically study the NC stretching mode of two model compounds, 5-isocyano...
Electronic spectral parameters, viz. Judd-Ofelt (T λ = T 2 , T 4 , T 6 , T 4 /T 6 and T 4 /T 2), and bonding parameters (β, δ% 1/2 and η have been evaluated for saturated solutions of eight ligands having N, S & O donor atoms, doped with Tm (III) ion. The change in symmetry around Tm (III) and covalency in M-L interaction has been observed.
The 2-(2,7-bis(pyridin-3-ylethynyl)fluoren-9-ylidene)malononitrile (1) was synthesized by reaction of 2,7-bis(pyridin-3-ylethynyl)fluoren-9-one with malononitrile in DMSO solution. The structural characterization of 1 by SC-XRD analysis was accompanied by elemental analysis, FT-IR, NMR, and MS measurements.
Dimension growth of metal halides is important for its properties and applications. However, such dimension control of the metal halides is rarely reported in the literature and the growth mechanism is not clear yet. A minute difference of solvent properties can tremendously alter the process of nucleation and growth of crystals. Herein, an intrigu...
An efficient protocol for the synthesis of substituted oxazoles via an annulation of ketones, DMSO, and ammonium is reported. DMSO is first found to serve as oxygen donor in annulation resulting in regioselective synthesis of 2,4‐disubstituted oxazoles. With the optimized conditions in hand, 22 examples of 2,4‐disubstituted oxazoles are obtained fr...
Citations
... It's hard to determine which contribution overpowers the other, since most studies conducted, neglect the effect of the other while reporting. From the perspective of the electrolyte, the stability of the superoxide in the electrolyte depends on the counteraction [124]. As observed in K-O 2 batteries, since K 2 O 2 is not highly stable, long-life stability can be found with the superoxide (KO 2 ) [125]. ...
The development of high-performance Li-air batteries (LABs) is an important quest for effectively utilizing high-energy density electric systems. One possible way to achieve this goal is by introducing novel bifunctional electrocatalysts at the battery cathode, enhancing the cycle life and the discharge capacity of the LABs by facilitating fast oxygen reaction kinetics. Understanding bifunctional catalysts' function and evolution is essential to developing a better-functioning LAB. In this review, we discuss the fundamentals, mechanisms, and key concepts related to LAB technology. We then provide critical discussions on recent advances in bifunctional catalysts used in LAB cathodes through material characterization, electrochemical analysis, battery performance, in-situ and ex-situ discharge product analysis, DFT calculations, and theoretical concepts to provide the most up-* Corresponding author. 2 to-date, thorough, and broader discussion on the subject. These include the general and modified catalysts of carbon nanostructures, noble metals, transition metal oxides, nitrides, sulfides, and phosphides. Furthermore, special attention is given to techniques designed to enhance the catalytic activity of LABs through the modulation of electronic structures. Various facet engineering and e g electron engineering approaches are explored, including heteroatom doping, alloying, hybridization, stoichiometric optimization, and selective facet growth. Finally, we suggest potential prospective pathways for future research.
... 447,448 Among the components used for these batteries, electrolytes play the most pivotal role in determining battery performance due to their influence on cell electrochemistry, chemical stability against oxides, and reversibility. [449][450][451][452] In fact, the chemical stability of the electrolyte (or lack thereof) against the highly reactive intermediates generated during the charge-discharge processes presents an inordinate challenge to the cycle life of M-O 2 batteries. For example, the carbonate-based electrolytes, some of the most prevalent electrolytes, have been expunged from air battery applications due to their susceptibility to oxygen reduction reaction (ORR) products. ...
The development of future energy devices that exhibit high safety, sustainability, and high energy densities to replace the currently dominant lithium-ion batteries has gained significant attention in recent years. Although the various energy devices available have different technological requirements, electrolyte formulation still remains a fundamental element of these state-of-the-art systems. Among the trending electrolyte contenders, ionic liquids, which are entirely comprised of cations and anions, provide a combination of several unique physicochemical and electrochemical properties, and exceptional safety. In this review, the fundamental properties of IL, their progress and milestones, and the directions for their future development and applications in next-generation energy devices are summarized. Each section will comprehensively review the latest progress and technology trends utilizing IL electrolytes focusing on Li-, Na-, K-ion batteries, metal anode batteries, sulfur and oxygen batteries, multivalent metal-ion batteries, and supercapacitors, with early studies mentioned where relevant. The benefits of using ionic liquid electrolytes on each system and pertinent improvements in performance are delineated in comparison to systems utilizing conventional electrolytes. Finally, prospects and challenges associated with the applications of ionic liquid electrolytes to future energy devices are also discussed.
... As discussed earlier, preparation of stable NaO 2 is the key barrier in the realization of sodium-air batteries. This instability is attributed to discharge product of sodium superoxide is reversibly oxidized toward oxygen as compared to peroxide and oxide [19]. The rechargeable room-temperature battery application of NaO 2 was demonstrated by Hartmann et al. ...
In the present work, we successfully prepared sodium superoxide (NaO2) doped vanadium phosphate borate glasses using normal melt quenching technique of composition 60V2O5–5P2O5–(35-x) B2O3–xNaO2, x = 0, 10, 15 and 20 mol %. The foremost objective of this work is to explore the transport properties of sodium superoxide doped vanadium phosphate borate glasses. The impedance spectroscopy was employed to investigate transport properties of all glass systems under study. The AC conductivity for all glass systems were investigated in temperature range 308–473 K. The Jonscher's power law found to be fit with conductivity data, which decrease with temperature and satisfies the criteria of the correlated hopping model. The activation energy (Ea) estimated from the Arrhenius plot and it is observed to be 0.12 eV.
... Although several key aspects of metal/air batteries are still not fully understood, it is now established that discharging and charging of such batteries involves complex dissolution and precipitation processes at the oxygen electrode [297]. Therefore, the electrode reaction can be influenced by numerous factors (current, type of solvent and electrolyte salt, impurities) [298][299][300]. Currently, the most important challenge to be solved for the oxygen electrode is to tame the role of singlet oxygen ( 1 O 2 ) that forms at all stages during cycling causing parasitic side reactions with the organic electrolyte and the carbon electrode [301,302]. ...
Several emerging battery technologies are currently on endeavour to take a share of the dominant position taken by Li-ion batteries in the field of energy storage. Among them, sodium-based batteries offer a combination of attractive properties i.e., low cost, sustainable precursors and secure raw material supplies. Na-based batteries include related battery concepts, such as Na-ion, all solid-state Na batteries, Na/O2 and Na/S, that differ in key components and in redox chemistry, and therefore result in separate challenges and metrics. Na-ion batteries represent an attractive solution which is almost ready to challenge Li-ion technology in certain applications; the other cell concepts represent a more disruptive innovation, with a higher performance gain, provided that major hurdles are overcome. The present review aims at highlighting the most promising materials in the field of Na-based batteries and challenges needed to be addressed to make this technology industrially appealing, by providing an in-depth analysis of performance metrics from recent literature. To this end, half-cell reported metrics have been extrapolated to full cell level for the more mature Na-ion technology to provide a fair comparison with existing technologies.
... Energies 2020, 13, 5650 2 of 14 and the high reactivity of oxygen species formed during cycling [14,[18][19][20][21][22][23], the optimal utilization of cathodes is crucial when aiming for the highest capacities possible. ...
Using sodium metal in sodium-oxygen batteries with aprotic electrolyte enables achieving a very high theoretical energy density. However, the promised values for energy density and capacity are not met in practical studies yet due to poor utilization of the void space in the cathode during battery discharge. In this work, we achieve better cathode utilization and higher discharge capacities by using pulse discharging. We optimize the chosen resting-to-pulse times, the applied current density, and elucidate that three-dimensional cathode materials yield higher capacities compared to two-dimensional ones. By implication, the pulse discharging mode ensures better supply with dissolved oxygen within the cathode. The higher amount of dissolved oxygen accumulated during the resting period after a current pulse is essential to form more of the discharge product, i.e., the metal oxide sodium superoxide. Interestingly, we show for the first time that the superoxide is deposited in a very unusual form of stacked and highly oriented crystal layers. Our findings on the pulse discharging can be transferred to other metal-oxygen battery systems and might assist in achieving their full potential regarding practical energy density.
... Traditionally, MABs use a metal anode and an air cathode consuming oxygen directly from ambient air (Li and Lu, 2017;Liu et al., 2017;Lao-Atiman et al., 2019). Several types of MABs have been developed e.g., lithium-air (Nomura et al., 2017;Yoo et al., 2017), sodium-air (Dilimon et al., 2017), zinc-air (Hosseini et al., 2018bAbbasi et al., 2019), magnesium-air Shrestha et al., 2019), and aluminum-air (Hong and Lu, 2017;Mori, 2017). During discharge, oxidation of the metal anode arises, whilst oxygen reduction reaction (ORR) takes place at the air cathode. ...
Aluminum-air batteries (AABs), due to their low cost and high specific capacity, receive much attention nowadays. Nonetheless, a vital problem curbing wide application of AABs is corrosion of the aluminum (Al) anode, which is triggered by hydrogen evolution reaction (HER). Therefore, this work tackles the problem of anode corrosion in an alkaline Al-air flow battery (AAFB) by implementing a dual-electrolyte system. The battery configuration consists of an Al anode | anolyte | anion exchange membrane | catholyte | air cathode. The anolytes in this work are ethylene glycol/ethanol solutions (0, 5, 10, 20, and 30%) v/v containing 3 M potassium hydroxide (KOH). A polymer gel electrolyte (Carbopol® 940) is employed as the catholyte. The corrosion of an Al electrode in the anolytes is duly examined. It is significant that when the ratio of ethylene glycol exceeds 5% v/v, this negatively affects the dissolution process and suppresses Al corrosion. Furthermore, the battery using the anolyte with 5% v/v ethylene glycol, at a discharge current density of 5 mA/cm2, demonstrates peak power of 3.75 mW/cm2. The battery also exhibits the highest specific discharge capacity of 2,100 mAh/gAl (70% utilization of Al) at a discharge current density of 2.5 mA/cm2. In general, the dual-electrolyte system affirms its effectiveness in controlling anodic corrosion, quelling passivation of the Al surface in the alkaline AABs and boosting discharge capacity. KOH in ethylene glycol/ethanol solution is a promising anolyte being more environmentally friendly, less toxic and providing favorable electrochemical performance.
... In principle, the negative effect of issues related to Na metal anode can be circumvented by replacing Na metal with a sodium alloy/compound or Na-ion intercalation materials. For example, to prevent the undesired reaction between Na metal and dimethyl sulfoxide-based electrolyte, presodiated antimony, Na-Sb alloy, was adopted as an anode material in Na-O 2 batteries by Dilimon et al. 119 Li-Na alloy as anode material has also been studied, and a novel bimetallic Li-Na alloy-O 2 battery was successfully developed. 120 However, the dendrite growth and huge volume expansion of Li-Na anode during repeated cycling still restrict the long-term cycling of the electrode, and thus electrolyte additives were adopted to achieve Li-Na alloy-O 2 battery with significantly improved cycling stability. ...
Na‐O2 batteries are advantageous as the candidates of next‐generation electric vehicles due to their ultrahigh theoretical energy density and have attracted enormous attention recently. Tremendous efforts have been devoted to improve the Na‐O2 battery performance by designing advanced electrodes with various carbon‐based materials. Carbon materials used in Na‐O2 batteries not only function as the air electrode to provide active sites and accommodate discharge products but also as Na anode protectors against dendrite growth and chemical/electrochemical corrosion. In this review, we mainly focus on the application of various carbon‐based materials in Na‐O2 batteries and highlight their advances. The scientific understanding on the fundamental design of the material microstructure and chemistry in relation to the battery performance are summarized. Finally, perspectives on enhancing the overall battery performance based on the optimization and rational design of carbon‐based cell components are also briefly anticipated. Na‐O2 batteries have attracted extensive research attentions due to their high theoretical energy density and energy efficiency. A variety of carbon materials have been developed with the aim of improving the Na‐O2 battery performance, and the roles that carbon materials play are evolving from a sole air electrode to functional core components in Na‐O2 batteries.
... 9 Guanidine disuperoxide is stable at ordinary temperatures and the solvent can be distilled off. 10 As a rule, salts of organic bases and weak acids, such as peroxides and superperoxides, are fusible substances. 11 The oxygen balance of guanidine disuperoxide is positive, therefore, it can serve as an oxidizer of rocket fuel. ...
Room‐temperature sodium‐sulfur (RT‐Na/S) batteries are promising alternatives for next‐generation energy storage systems with high energy density and high power density. However, some notorious issues are hampering the practical application of RT‐Na/S batteries. Besides, the working mechanism of RT‐Na/S batteries under practical conditions such as high sulfur loading, lean electrolyte, and low capacity ratio between the negative and positive electrode (N/P ratio), is of essential importance for practical applications, yet the significance of these parameters has long been disregarded. Herein, it is comprehensively reviewed recent advances on Na metal anode, S cathode, electrolyte, and separator engineering for RT‐Na/S batteries. The discrepancies between laboratory research and practical conditions are elaborately discussed, endeavors toward practical applications are highlighted, and suggestions for the practical values of the crucial parameters are rationally proposed. Furthermore, an empirical equation to estimate the actual energy density of RT‐Na/S pouch cells under practical conditions is rationally proposed for the first time, making it possible to evaluate the gravimetric energy density of the cells under practical conditions. This review aims to reemphasize the vital importance of the crucial parameters for RT‐Na/S batteries to bridge the gaps between laboratory research and practical applications.
