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In this paper, we focus on an innovative sulfur doping method with MOF-5 and inorganic sulfur powders as templated carbon precursor and sulfur source, in which sulfur powders were firstly encapsulated into the abundant pore structure of MOF-5 and then sulfur doping process could be realized through further pyrolysis treatment. Based on the results of material characterization, sulfur-doped mesoporous carbon (SPC) holds an amorphous structure with an enlarged interlayer distance of 0.386 nm and a mesoporous size distribution of 3–6 nm, while sulfur atoms existing in SPC (2.5 at.%) are mainly in the form of thiophene-type bonds (C S C and C S). Benefitting from the structural advantages, SPC electrode could display a long-term cycling stability with a reversible capacity of 173.7 mAh g −1 at 200 mA g −1 after 500 cycles and an outstanding rate capability of 104.9 and 90 mAh g −1 even the current raised up to 1.6 and 3.2 A g −1 , respectively. The enhanced electrochemical performances could be mainly attributed to the introduction of S atoms into carbon structure, which can effectively enlarge the interlayer distance, improve the electronic conductivity and promote the insertion/extraction process of sodium storage. [ABSTRACT FROM AUTHOR]

Aqueous hybrid ion batteries (AHIB) are being promoted as an environmentally friendly alternative to existing stationary battery technologies. However, no quantification of their potential environmental impacts has yet been done. This paper presents a prospective life cycle assessment of an AHIB module and compares its performance with lithium-ion and sodium-ion batteries in two different stationary energy storage applications. The findings show that the claim of being an environmentally friendly technology can only be supported with some major limitations. While the AHIB uses abundant and non-toxic materials, it has a very low energy density and requires increased amounts of material for providing a given storage capacity. Per kWh of battery, results comparable to those of the alternative lithium- or sodium-ion batteries are obtained, but significantly higher impacts under global warming and ozone depletion aspects. The comparable high cycle life of the AHIB compensates this partially, requiring less battery replacements over the lifetime of the application. On the other hand, its internal inefficiencies are higher, what becomes the dominating factor when charging majorly fossil based electricity, making AHIB unattractive for this type of applications. [ABSTRACT FROM AUTHOR]

Bulk-type all-solid-state Na/S cells, which are expected to have high capacity, be highly safe, and have low material cost, were fabricated using a Na3PS4 glass-ceramic as a solid electrolyte. The sulfur composite electrodes were prepared by mechanical milling of sulfur active material, a conductive additive (acetylene black), and a Na3PS4 glass-ceramic electrolyte. The all-solid-state Na/S cells used the reaction up to the final discharge product of sulfur active material, Na2S, and achieved a high capacity of ~1100 mAh (g of S)-1 at room temperature. The rate of utilization of sulfur active material was ~2 times higher than that of high-temperature-operating NAS batteries (commercially available NAS batteries, Na/sintered β"-alumina/S), where Na2Sx melts with bridging sulfurs contribute to redox in the sulfur electrodes. The open circuit potential curve of the discharge process of the Na/S batteries operating at room temperature was similar to that of the NAS batteries operating at high temperatures; X-ray diffraction and X-ray photoelectron spectroscopy measurement indicated that amorphous Na2Sx with a structure similar to the structure of these melts contributed to sulfur redox reaction in the all-solid-state Na/S cells. A galvanostatic intermittent titration technique and impedance measurement suggested that the overpotential during the discharge process in the all-solid-state Na/S cells was mainly derived from the sodium diffusion resistance in the solid sulfur active material. The finding would be an effective guide for achieving higher performance for all-solid-state Na/S cells. [ABSTRACT FROM AUTHOR]

In this paper, the mathematical modelling of a novel Electrical Energy Storage (EES) Receiver for Solar Parabolic Trough Collector (PTC) is presented. The EES receiver is essentially a Heat Collecting Element (HCE) with built in storage in the form of thermal batteries such as the Sodium Sulphur (NaS) battery. The conceptual design and mathematical models describing the operation of the receiver are presented along with important results of model validation. When held under adiabatic conditions (a primary indicator of model validity), results were highly consistent with established PTC, models and with National Renewable Energy Laboratory (NREL, USA) experimental data for existing SCHOTT PTR-70 and Solel UVAC3 receiver tubes, currently being used in existing PTC power plants. [ABSTRACT FROM AUTHOR]

Published data on the phase diagram, thermodynamic properties, and electrochemical behavior of the sodium-sulfur system are considered. The use of this system in rechargeable chemical current sources (batteries) at different temperatures is discussed. [ABSTRACT FROM AUTHOR]

We demonstrate a room-temperature sodium sulfur battery based on a confining microporous carbon template derived from sucrose that delivers a reversible capacity over 700 mAh/gS at 0.1C rates, maintaining 370 mAh/gS at 10 times higher rates of 1C. Cycling at 1C rates reveals retention of over 300 mAh/gS capacity across 1500 cycles with Coulombic efficiency >98% due to microporous sulfur confinement and stability of the sodium metal anode in a glyme-based electrolyte. We show sucrose to be an ideal platform to develop microporous carbon capable of mitigating electrode-electrolyte reactivity and loss of soluble intermediate discharge products. In a manner parallel to the low-cost materials of the traditional sodium beta battery, our work demonstrates the combination of table sugar, sulfur, and sodium, all of which are cheap and earth abundant, for a high-performance stable room-temperature sodium sulfur battery. [ABSTRACT FROM AUTHOR]

Nanotube-based ion batteries have fascinated the researchers due to high cyclability, high capacity, and high energy density of nanotubes. Here, the application of BN nanotubes (BNNTs) and BN nanosheets in Na-ion batteries are explored using density functional theory calculations. Investigating the interaction of both Na and Na + with different BNNTs and BN nanosheet, we demonstrated that the cell voltage of Na-ion batteries increase by decreasing the structural curvature of the BN structures. Calculated cell voltage for the small (5, 0) BNNT and the BN nanosheet is about 1.12 and 1.55 V, respectively. The interaction of atomic Na with the surface of the BN structures plays the main rule in determining the cell voltage. Also, our calculations indicate that the aromaticity and hybridization of the atoms of BN structures affect the performance of Na-ion batteries. Based on the results, it can be understood that why the disk like BN sheets are more suitable than BNNTs for application in the anode electrode of Na-ion batteries. [ABSTRACT FROM AUTHOR]

Sodium ion batteries have garnered significant research attention in recent years due to the rising demand for large-scale energy storage solutions as well as the high abundance of sodium. P2-type layered oxide materials have been identified as promising positive electrode materials for sodium ion batteries. Previously, P2-Na2/3Ni1/3Mn2/3O2 was shown to have a high operating voltage and high capacity but suffers from a step-like voltage curve and capacity loss during cycling, potentially due to its P2-O2 transition at high voltages. One strategy to improve cycling performance has been to dope Ni2+ with other 2+ cations, such as Zn2+ or Mg2+, which improved capacity retention but significantly decreases reversible capacity, since these ions were not electrochemically active. Since Cu2+ has been shown to be electrochemically active, we replaced Ni2+ with Cu2+, resulting in air-stable Na2/3Ni1/3-xCuxMn2/3O2 (0 ≤ x ≤ 1/3). Both Ni2+/Ni4+ and Cu2+/Cu3+ participate in the redox reaction during cycling, capacity retention was greatly improved, and phase changes were suppressed during cycling without sacrificing much capacity. The material retains a P2/OP4 structure even when cycled to high voltages. The doping strategy is a promising approach for the future development of positive electrode materials for sodium ion batteries. [ABSTRACT FROM AUTHOR]

Room temperature sodium-sulfur (RT Na-S) batteries demonstrate a high theoretical energy density, but their practical application is limited by the sodium polysulfides (NaPSs) shuttling and slow redox kinetics. Herein, we report the design of the dimensional hybrid structure of 2D ZIF-67 nanosheets and 3D ZIF-67 polyhedron on the surface of carbon fiber by a pseudomorphic replication approach. After pyrolysis in ammonia, a hybrid structure composed of 2D N-doped carbon nanosheets and 3D N-doped carbon nano-polyhedrons embedded with Co 4 N nanoparticles (denoted as 2D/3D Co 4 N-NC@CC) is designed as a sulfur host for RT Na-S battery. The complex structure of 2D/3D composite guarantees abundant adsorption and catalytic sites, accelerating electrons/mass transport abilities compared with single 2D or 3D structure, in which Co 4 N can effectively catalyze the conversion of NaPSs and inhibit "shuttling effect". Consequently, the RT Na-S cell with 2D/3D Co 4 N-NC@CC cathode exhibits extra-high discharge capacity of 466 mAh g−1 at 3.0 C and an outstanding long-term cycling stability (592 mAh g−1 at 1.0 C after 1000 cycles). The hybrid 2D/3D Co 4 N-NC@CC with excellent electrochemical performance represents a potential candidate for developing advanced RT Na-S batteries and other energy storage systems. [ABSTRACT FROM AUTHOR]

Room-temperature sodium-sulfur (RT Na–S) batteries have been getting increasing attention in the field of energy storage system thanks to their advantages of high specific capacity, good safety, low cost and environmental friendliness. However, limited by the low conductivity, large volume change and complex reaction, the utilization rate of active sulfur is still unacceptable, which delays the practical application of RT Na–S battery. Herein, derived from CoZn-ZIFs, a cobalt, nitrogen co-doped microporous carbon matrix (Co,N-MPC) has been devised to exploit capacity of active sulfur as fully as possible. In the case of appropriate Co content, the affluent micropores limit the size of sulfur and inhibit the volume change. And the well-dispersed Co and N elements improve the adsorption of the matrix to sulfur species and promote their transformation process. Owing to their synergistic effect, the S@Co,N-MPC-10% electrode presents stable cycling (1134.63 mAh g−1 after 100 cycles at 0.2 C) and high rate capacity (835.01 mAh g−1 at 3.0 C). This work might provide beneficial insights to the development of efficient sulfur matrixes of RT Na–S batteries. [Display omitted] • A series of cobalt, nitrogen co-doped carbon matrixes were synthesized. • The affluent micropores limit the size of sulfur and inhibit the volume change. • The Co and N elements have the strong interaction with sulfur species. • These micropores and interaction lead to an improved electrochemical performance. [ABSTRACT FROM AUTHOR]

Despite the high theoretical capacity of the sodium–sulfur battery, its application is seriously restrained by the challenges due to its low sulfur electroactivity and accelerated shuttle effect, which lead to low accessible capacity and fast decay. Herein, an elaborate carbon framework, interconnected mesoporous hollow carbon nanospheres, is reported as an effective sulfur host to achieve excellent electrochemical performance. Based onin situsynchrotron X-ray diffraction, the mechanism of the room temperature Na/S battery is proposed to be reversible reactions between S8and Na2S4, corresponding to a theoretical capacity of 418 mAh g–1. The cell is capable of achieving high capacity retention of ∼88.8% over 200 cycles, and superior rate capability with reversible capacity of ∼390 and 127 mAh g–1at 0.1 and 5 A g–1, respectively. [ABSTRACT FROM AUTHOR]

Honey, a widely existent biomass, consists mainly of carbohydrate and other nitrogen-containing substances such as proteins, enzymes and organic acids. It can be mixed homogeneously with mesoporous silica template for its excellent water-solubility and moderate viscosity. In this work, honey was employed as a nitrogen-containing carbon precursor to prepare nitrogen-doped ordered mesoporous carbons (OMCs). The obtained honey derived mesoporous nitrogen-doped carbons (HMNCs) with dilated interlayer spacings of 0.387–0.395 nm, narrow pore size distributions centering at around 4 nm and satisfactory N contents of 1.38–4.32 wt% offer superb dual functionality for lithium ion battery (LIB) and sodium ion battery (NIB) anodes. Tested against Li, the optimized HMNC-700 delivers a superior reversible capacity of 1359 mA h g −1 after 10 cycles at 100 mA g −1 and excellent rate capability and cycling stability of 722 mA h g −1 after 200 cycles at 1 A g −1 . For NIB applications, HMNC-700 offers a high initial reversible capacity of 427 mA h g −1 and stable reversible capacity of 394 mA h g −1 at 100 mA g −1 . [ABSTRACT FROM AUTHOR]

Although well-known and studied for centuries, sulfur continues to be at the center of an extensive array of scientific research topics. As one of the most abundant elements in the Universe, a major by-product of oil refinery processes, and as a common reaction site within biological systems, research involving sulfur is both broad in scope and incredibly important to our daily lives. Indeed, there has been renewed interest in sulfur-based reactions in just the past ten years. Sulfur research spans the spectrum of topics within the physical sciences including research on improving energy efficiency, environmentally friendly uses for oil refinery waste products, development of polymers with unique optical and mechanical properties, and materials produced for biological applications. This Review focuses on some of the latest exciting ways in which sulfur and sulfur-based reactions are being utilized to produce materials for application in energy, environmental, and other practical areas. [ABSTRACT FROM AUTHOR]

• Anhydrous Ce(NO 3) 4 is a novel bi-functional additive for RT Na-S batteries. • Ce(NO 3) 4 generates NaCeO 2 and NaNO 3 and accelerates the NaF formation. • NaCeO 2 and NaF show excellent chemical stability after long-term cycling. • Ce4+ effectively captures and evenly re-deposits polysulfides on the S cathode. Room-temperature sodium-sulfur batteries face enormous challenges in the coulombic efficiency, capacity retention, and rate performance, which are seriously related to the solid electrolyte interface film, the shuttle effect of polysulfide, and the sodium-sulfur reaction kinetics. Adjusting the electrolyte composition by additives can significantly improve the battery performance and is attracting tremendous attention. However, the reported additives mainly focus on one of the two electrodes. It is still a considerable challenge to balance both aspects. This work proposes a novel dual-functional additive, Ce(NO 3) 4 , and studies its comprehensive influence on the battery performance by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and electrochemical techniques. The results show that Ce(NO 3) 4 generates NaCeO 2 and NaNO 3 to deposit on the Na surface. This inert deposition layer inhibits the side reactions between Na and polysulfides and optimizes the Na dissolution/deposition process, thereby improving the cycle stability of the battery. In addition, Ce4+ has a strong adsorption effect on capturing and evenly depositing polysulfides on the S cathode to inhibit the shuttle effect. In short, the Ce(NO 3) 4 additive plays a dual function of protecting the Na anode and optimizing the S cathode reaction. [ABSTRACT FROM AUTHOR]

Sodium secondary batteries are attracting considerably renewed interest as new battery systems owing to the high and uniform abundance and cost advantages of Na. However, their performance is still far from optimal as compared to the well-developed Li-ion technology. Herein, Na secondary batteries with unprecedented rate capability and a long life has been achieved by using a highly concentrated bis(fluorosulfonyl)amide anion (FSA – )-based ionic liquid electrolyte (3.3 mol dm −3 Na[FSA]) and a Na 2 FeP 2 O 7 positive electrode, in a targeted operating temperature range from room to intermediate. Nearly full discharge capacity is obtained at 4000 mA g −1 , and 79% of the capacity is retained at a discharge rate as high as 20000 mA g −1 at 363 K. Stable cycling (>300 cycles) with satisfactory coulombic efficiency (>99.5%) is found at an intermediate rate (100 mA g −1 ) over 298–363 K. A high-rate cycling test (1000 mA g −1 ) at 363 K reveals that the cell could retain 93% of its initial capacity after 1500 cycles. [ABSTRACT FROM AUTHOR]

Transition metal oxides have recently aroused a renewed and increasing interest as conversion anode materials for sodium ion batteries. Being their electrochemical performances strongly dependent on morphological aspects, has been here proposed a straightforward approach to modulate morphological characteristics of a transition metal oxide (Co 3 O 4 ) using a low cost synthetic route. The as obtained optimized morphology allows the realization of high practical specific capacities, higher than 500 mAh g −1 after 50 cycles, and represents a valid candidate for further optimization. In addition to the morphology-performance correlations, the reaction mechanism beyond the electrochemical behavior was also investigated revealing the role of the CoO phase in the charge/discharge process. Finally, an electrode pre-sodiation treatment for conversion materials is presented: it has been indeed demonstrated that it sensibly decreases the irreversible capacity correlated to the first cycle and improves cycle ability. [ABSTRACT FROM AUTHOR]

Solid-state reactions are a simple and scalable synthetic method, but they lack controlled nanostructures at present. Here, we report an energy-efficient solid-state synthesis, via the addition of carbon, to mass-produce uniform, single-crystalline, one-dimensional metal oxide nanorods with tunable composition according to performance demands. The carbon added in the solid-state reaction provides an alternative low-temperature route for the metal oxide formation due to the extra local heat generation and CO2/CO release from carbon oxidation. To demonstrate the methodology, a series of single-crystalline Na2Ti3O7/Na2Ti6O13 nanorods with tunable composition are synthesized and applied in sodium-ion batteries. The local heat generated from carbon allows formation of Na2Ti3O7 at 450 °C, a reaction temperature much lower than that of conventional solid-state methods (750-1000 °C), and Na2CO3 is regenerated to be recycled in the synthesis. The high theoretical capacity of Na2Ti3O7 and low volume expansion of Na2Ti6O13 upon charge-discharge are synergistically exploited to achieve high electrochemical performance and stability. [ABSTRACT FROM AUTHOR]

A novel sulfate material, Na 2 Fe 2 (SO 4 ) 3 , was recently proposed as a high-density cathode material for sodium-based batteries (Barpanda et al. , 2014). This study presents ab initio simulations describing the effect of partial oxygen-to-nitrogen substitution in this material with the aim of increasing the sodium capacity of the structure as well as its energy density. The considered structure with the most likely substitution configuration increases the theoretical energy density to 650 W h kg −1 , improving over the theoretical value of 480 W h kg −1 for the original, nitrogen-free structure. [ABSTRACT FROM AUTHOR]

We introduce a comprehensive finite-element analysis (FEA) computational model to accurately predict the thermo-mechanical stresses at heterogeneous joints and components of large-size sodium sulfur (NaS) cells during thermal cycling. Quantification of the thermo-mechanical stress is important because the accumulation of stress during cell assembly and/or operation is one of the critical issues in developing practical planar NaS cells. The computational model is developed based on relevant experimental assembly and operation conditions to predict the detailed stress field of a state-of-the-art planar NaS cell. Prior to the freeze-and-thaw thermal cycle simulation, residual stresses generated from the actual high temperature cell assembly procedures are calculated and implemented into the subsequent model. The calculation results show that large stresses are developed on the outer surface of the insulating header and the solid electrolyte, where component fracture is frequently observed in the experimental cell fabrication process. The impacts of the coefficients of thermal expansion (CTE) of glass materials and the thicknesses of cell container on the stress accumulation are also evaluated to improve the cell manufacturing procedure and to guide the material choices for enhanced thermo-mechanical stability of large-size NaS cells. [ABSTRACT FROM AUTHOR]

An innovative electronically-conducting cathode matrix, that makes sodium sulfur (NaS) battery excellent in discharge-charge performance, is prepared by surface modification of a carbon felt with inorganic nanoparticles. A carbon felt is dipped into an inorganic-organic hybrid sol, dried, and heat-treated at 600 °C for 2 h in a flowing argon. Coated surface of the felt has been examined by scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX) and scanning transmission electron microscopy (STEM). The cell prepared with the coated carbon felt shows 92% of charge acceptance and 99.9% of coulombic efficiency at 100 mA cm −2 of current density. [ABSTRACT FROM AUTHOR]

Two phase samples containing ~ 30 vol.% of 3 mol% Y 2 O 3 -stabilized zirconia (TZ-3Y) and ~ 70 vol.% of α-Al 2 O 3 doped with 5 mol% Fe 2 O 3 were fabricated by sintering powder compacts in air at 1450 °C. The added Fe 2 O 3 was fully dissolved in Al 2 O 3 as determined by X-ray diffraction. The two phase samples were packed in Na-β”-alumina powder of nominal composition 8.85 wt.% Na 2 O, 0.75 wt.% Li 2 O and balance Al 2 O 3 and heat treated in air at 1250 °C for 20 h. The samples were sectioned, polished and examined by X-ray diffraction, optical microscopy and scanning electron microscopy. The as-sintered samples were ~ 97% of theoretical density with an approximate grain size of ~ 0.8 μm. In the samples packed in Na-β”-alumina powder and heat treated in air, Fe-doped α-Al 2 O 3 converted into Fe-doped Na-β”-alumina. A sample of 2.35 mm in thickness could be fully converted into iron-doped Na-β”-alumina in 17 h at 1450 °C. Ionic conductivity was measured by electrochemical impedance spectroscopy (EIS) over a temperature range from 197 °C to 485 °C. The bulk conductivity of the converted sample exhibited Arrhenius behavior with an activation energy of 0.20 eV and a pre-exponential factor of 421 Ω − 1 cm − 1 K. [ABSTRACT FROM AUTHOR]

A novel combination of hard carbon anode sodium pre-loading and a tailored electrolyte is used to prepare room temperature sodium-sulfur full cell batteries. The electrochemical loading with sodium ions is realized in a specific mixture of diethyl carbonate, ethylene carbonate, and fluoroethylene carbonate electrolyte in order to create a first solid electrolyte interface (SEI) on the anode surface. Combining such anodes with a porous carbon/sulfur composite cathode results in full cells with a significantly decreased polysulfide shuttle when compared to half cells combined with metallic sodium anodes. Further optimization involves the use of Na2S/P2S5 doped tetraethylene glycol dimethyl ether based electrolyte in the full cell for the formation of a second SEI, reducing polysulfide shuttle even further. More importantly, the electrochemical discharge processes in the cell are improved by adding this dissolved complexation agent to the electrolyte. As a result of this combination sodium-sulfur cells with tailored cathode materials and electrolytes can achieve high discharge capacities up to 980 mAh g−1sulfur and 1000 cycles with 200 mAh g−1sulfur remaining capacity, at room temperature. [ABSTRACT FROM AUTHOR]

For the design of light-metal-sulfur batteries and for the understanding of their performance, knowledge on the stable crystalline polysulfides is very important. We confronted experimental and ab initio crystal structure prediction studies on the stability of Na polysulfides. The selected evolutionary-based structure-prediction algorithm was able to quickly and correctly predict the thermodynamically stable crystalline forms of Na polysulfides with small unit cells. For Na polysulfides with large unit cells, the algorithm correctly proposed short unbranched polysulfide chains to be energetically favorite structural motifs, but could not find proper three-dimensional structures in the limited number of generations. Experimentally, the polysulfides were studied by X-ray diffraction and 23Na solid-state NMR spectroscopy. Complemented by calculations of the isotropic chemical shifts and quadrupolar coupling constants, NMR spectroscopy proved to be an excellent tool for the examination of Na polysulfides, because it allowed easy distinction and quantification of components in the samples. [ABSTRACT FROM AUTHOR]

Operation of sodium-sulfur batteries at room temperature has been proposed and studied for about a decade, but polysulfide-shuttle through the traditional battery separator and low-utilization of the sulfur cathode commonly have been the major challenges. Also, because of the highly active nature of the sodium metal, the conventional room temperature sodium-sulfur (RT Na-S) battery concept with the sodium-metal anode and elemental sulfur cathode imposes serious safety concerns. To overcome the above difficulties, we present here a RT Na-S system with an advanced membrane-electrode-assembly (MEA) comprising a carbon-coated, presodiated Nafion membrane (Na-Nafion) and a sodium sulfide (Na2S) cathode. The Na-Nafion membrane provides a facile Na+-ion conductive path and serves as a cation-selective shield to prevent the migration of the polysulfides to the anode. The carbon coating on the Na-Nafion plays an upper-current-collector role and thereby improves the electrochemical utilization of the active Na2S. Employing Na2S as the cathode provides a pathway to develop the RT Na-S batteries with sodium-metal-free anodes. The RT Na-S battery with the above MEA exhibits remarkably enhanced capacity and cyclability in contrast to the Na-S batteries with the conventional electrolyte-separator configuration. Mechanistic studies reveal that the suppression of polysulfide migration through the Na-Nafion is due to size and electronic effects. [ABSTRACT FROM AUTHOR]

The sulfur-based cathode materials suffer severely from poor cycling stability and low utilization, incurred by their stepwise reaction mechanism that generates polysulfide intermediates and the subsequent irreversible losses. In this work, those issues are significantly relieved by entrapping sulfur species in carbon host rich in oxygen functionalities. Sulfur species in such C/S composite are highly stabilized by their interaction with oxygen, and can deliver a reversible capacity of 508 mAh/(g of S) for 2000 cycles when coupled with Li, representing the best cycling stability up to date. More interestingly, extra capacity can be accessed by simply prelithiating the oxygen-stabilized C/S composites down to 0.6 V for a few cycles, which enables a high capacity of 1621 mAh/(g of S) that eventually stabilizes at 820 mAh/(g of S) for 600 cycles. The mechanism for this electrochemical activation process is investigated with both spectroscopic and electrochemical techniques, which reveal that the inactive sulfur bonded to oxygen is liberated in the initial deep lithiation precycles and becomes electrochemically active. The oxygen-stabilized sulfur can also be coupled with Na anode to form Na/S cell, confirming that the formation of S−O interaction in C/S composite generates promising sulfur-based cathode materials for Li-S and Na-S batteries. [ABSTRACT FROM AUTHOR]

The merits of electricity grid in Shanghai and sodium sulfur (NaS) storage techniques situation are introduced. High-energy NaS battery energy storage system (BESS) is very suitable for peak shaving of electricity grid. A cost-benefit analysis model of NaS BESS is established to study the electricity price mechanism in load shift in the light of an example of NaS BESS in Meisei University. Capacity price, energy price and twofold electricity price mechanism are discussed under the fixed payback period. The results show that twofold electric power price mechanism is fitter for NaS BESS than onefold energy price mechanism while onefold capacity price mechanism is not suitable for NaS BESS. The discharge price of NaS BESS has an advantage over Shanghai's electricity price in industrial and commercial peak periods when its construction cost descends to 1000 yuan kWh−1. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

To realize a high-performance room temperature Na/S battery with an elemental sulfur cathode, it is important that sodium polysulfides stay within the cathode and that they have room enough to react freely. In this work, sodium polysulfides are confined to the cathode using a β″ alumina solid electrolyte separator and an optimal amount of tetraethylene glycol dimethyl ether (TEGDME) electrolyte. In addition, an activated carbon material, in the form of a sulfur/carbon (S/C) composite, with high surface area, porosity, and pore volume is employed in the cathode. The resulting Na/S battery shows a high first discharge capacity of 855 mAh g −1 and coulombic efficiency close to 100%, as well as stable cyclability, with a discharge capacity of 521 mAh g −1 at the 104th discharge. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new strategy is provided to integrate sulfur on graphene-based host covalently (C-S x -C). • The well distribution of sulfur in the host is realized by vapor-infiltration method. • The covalently bonded sulfur inhibited the formation of soluble polysulfides during cycling. Application of emerging room temperature sodium-sulfur (RT Na-S) battery is restrained by the poor conductivity, volume expansion of sulfur cathode and the shuttle effect of soluble polysulfides in electrolytes. Herein, an N-doped two-dimensional (2D) carbon host was derived from the polydopamine coated graphene for sulfur storage. Different from the conventional used melt-diffusion method to integrate sulfur on graphene layer physically, we employed a vapor-infiltration method to realize the homogenous incorporation of sulfur in the graphene-based host via C-S x -C bond. A polydopamine-derived N-doped carbon layer was further coated on graphene to confine the high-temperature-induced gas-phase sulfur, which effectively increase the covalently bonded sulfur content in the host. Moreover, based on Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) measurement, the C-S bonds are mainly formed beside N-doped carbon, being well explained by the stronger interaction between N-doped carbon and S 4 (sulfur vapor) than that of pure carbon from density functional theory (DFT) calculation results. When tested as a cathode for RT Na-S battery, the obtained N-doped graphene/sulfur cathode shows superior cycle stability. [ABSTRACT FROM AUTHOR]

The practical application of the room-temperature sodium-sulfur (RT Na-S) batteries is hindered by the insulated sulfur, the severe shuttle effect of sodium polysulfides, and insufficient polysulfide conversion. Herein, on the basis of first principles calculations, single-atom vanadium anchored on a 3D nitrogen-doped hierarchical porous carbon matrix (denoted as 3D-PNCV) is designed and fabricated to enhance sulfur reactivity, and adsorption and catalytic conversion performance of sodium polysulfide. The 3D-PNCV host with abundant and active V sites, hierarchical porous structure, high electrical conductivity, and strong chemical adsorption/conversion ability of V-N bonding can immobilize the polysulfides and promote reversibly catalytic conversion of polysulfides toward Na 2 S. Therefore, as-fabricated RT Na-S batteries can achieve a high reversible capacity (445 mAh g -1 over 800 cycles at 5 A g -1 ) and excellent rate capability (224 mAh g -1 at 10 A g -1 ). The electrocatalysis mechanism of sodium polysulfides is further experimentally and theoretically revealed, which provides a new strategy to develop the highly stable RT Na-S batteries., (© 2022 Wiley-VCH GmbH.)

The practical applications of room-temperature sodium-sulfur (RT Na-S) batteries have been greatly hindered by the natural sluggish reaction kinetics of sulfur and the shuttle effect of sodium polysulfide (NaPSs). Herein, oxygen vacancy (OV)-mediated amorphous GeO x /nitrogen doped carbon (donated as GeO x /NC) composites were well designed as sulfur hosts for RT Na-S batteries. Experimental and density functional theory studies show that the introduction of oxygen vacancies on GeO x /NC can effectively immobilize polysulfides and accelerate the redox kinetics of polysulfides. Meanwhile, the micro-and mesoporous framework, acting as a reactor for storing active S, is conducive to alleviating the expansion of S during the charging/discharging process. Consequently, the S@GeO x /NC cathode affords a reversible capacity of 1017 mA h g -1 at 0.1 A g -1 after 100 cycles, outstanding rate capability of 333 mA h g -1 at 10.0 A g -1 and long lifespan cyclability of 385 mAh g -1 at 1 A g -1 after 1200 cycles. This work furnishes a new way for the rational design of metal oxides with oxygen vacancies and boosts the application for RT Na-S batteries., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

A numerical prediction model is developed for the safety analysis of molten sodium–sulfur battery. Under the assumption that a crack occurred in a solid electrolyte of a cell, a rapid increase in the temperature and pressure from a direct reaction between sulfur and sodium can be predicted by solving equations for flow, energy and the chemical reaction. The crack, the powder-type in-filler and the carbon felt in the sulfur electrode are modeled by porous media approximations. The results are compared to experimental results with extreme value probability statistics for the data assessment. The effects of the size of the cell and wick tube, the depth of discharge, and the filler material are summarized quantitatively. [ABSTRACT FROM AUTHOR]

Crete Island is rich in renewable energy resources such as wind and solar. Likewise other European territories, renewable sources already are being explored for power production. Currently a large amount of wind energy on Crete is curtailed during certain daily periods as a result of reduced demand and minimum operating levels on thermal generators. Reducing wind power curtailment magnitude requires additional sources of flexibility in the grid, and electric energy storage is one of them. This paper address wind generation curtailment minimization through the storage of wind energy surplus. NaS (sodium sulfura) battery modelling is used in this study in order to shift wind generation from off-peak to on-peak through a technical-economic analysis, considering the total annualized cost of the storage system and the wind power curtailment based on an annual basis. The obtained results are based on real data, which includes Crete Island demand, renewable and conventional power generation. [ABSTRACT FROM AUTHOR]

Corrosion characteristics of hypo-eutectic Al–1Mg– x Si alloys, which can be used as insert metals of thermal compression bonding (TCB) joints in sodium sulfur cells, have been studied to enhance the corrosion resistance of the alloys in molten sodium at the cell operation temperature of 325 °C. The results showed that the major corrosion product was a NaAlSi compound, and corrosion kinetics decreased as silicon concentration decreased without compromising the bonding strength. The parabolic rate constant of Al–1Mg–3Si alloys was smaller by 25.5% than that of Al–1Mg–12Si alloys. [ABSTRACT FROM AUTHOR]

In this paper, the environmental performance of electricity storage technologies for grid applications is assessed. Using a life cycle assessment methodology we analyze the impacts of the construction, disposal/end of life, and usage of each of the systems. Pumped hydro and compressed air storage are studied as mechanical storage, and advanced lead acid, sodium sulfur, lithium-ion and nickel–sodium-chloride batteries are addressed as electrochemical storage systems. Hydrogen production from electrolysis and subsequent usage in a proton exchange membrane fuel cell are also analyzed. The selected electricity storage systems mimic real world installations in terms of capacity, power rating, life time, technology and application. The functional unit is one kW h of energy delivered back to the grid, from the storage system. The environmental impacts assessed are climate change, human toxicity, particulate matter formation, and fossil resource depletion. Different electricity mixes are used in order to exemplify scenarios where the selected technologies meet specific applications. Results indicate that the performance of the storage systems is tied to the electricity feedstocks used during use stage. Renewable energy sources have lower impacts throughout the use stage of the storage technologies. Using the Belgium electricity mix of 2011 as benchmark, the sodium sulfur battery is shown to be the best performer for all the impacts analyzed. Pumped hydro storage follows in second place. Regarding infrastructure and end of life, results indicate that battery systems have higher impacts than mechanical ones because of lower number of cycles and life time energy. [ABSTRACT FROM AUTHOR]

A sodiated Nafion membrane significantly suppresses the polysulfide shuttling and enhances sulfur utilization and cyclability of the room‐temperature Na–S batteries. [ABSTRACT FROM AUTHOR]

This paper presents a comparative life cycle assessment of cumulative energy demand (CED) and global warming potential (GWP) of four stationary battery technologies: lithium-ion, lead-acid, sodium-sulfur, and vanadium-redox-flow. The analyses were carried out for a complete utilization of their cycle life and for six different stationary applications. Due to its lower CED and GWP impacts, a qualitative analysis of lithium-ion was carried out to assess the impacts of its process chains on 17 midpoint impact categories using ReCiPe-2008 methodology. It was found that in general the use stage of batteries dominates their life cycle impacts significantly. It is therefore misleading to compare the environmental performance of batteries only on a mass or capacity basis at the manufacturing outlet ("cradle-to-gate analyses") while neglecting their use stage impacts, especially when they have different characteristic parameters. Furthermore, the relative ranking of batteries does not show a significant dependency on the investigated stationary application scenarios in most cases. Based on the results obtained, the authors go on to recommend the deployment of batteries with higher round-trip efficiency, such as lithium-ion, for stationary grid operation in the first instance. [ABSTRACT FROM AUTHOR]

A positive effect of the polyacrylic acid (PAA)-carboxymethyl cellulose (CMC) binder to enhance the performance of an oxide-based anode was reported in batteries. A series of super high capacity and cycling ability oxide powders rarely achieved before was obtained, particularly most of them without any specific carbon modification and/or morphology control. [ABSTRACT FROM AUTHOR]

Abstract: Porous iron oxide films with controlled pore structure to modify the surface of β″-alumina ceramic electrolyte were synthesized through a low-cost wet chemistry method. The pore diameter of the iron oxide coatings can be tuned mainly by the amount of pore-forming agent polyethylene glycol. The iron oxide coatings were demonstrated to improve the wettability of the β″-alumina ceramics by molten sodium. Furthermore, Na/β″-alumina/Na cells were used to investigate the interfacial properties between sodium and the β″-alumina electrolytes. The results obtained at 350°C revealed that the coating effectively alleviated the Na/β″-alumina interfacial polarization. [Copyright &y& Elsevier]

Abstract: FeS2 synthesized by hydrothermal method was used for sodium batteries for the first time. A large initial discharge capacity of 771 mAh g− 1 and a high reversible capacity of 521 mAh g− 1 were obtained. The reaction mechanism of electrochemical de-sodiation (charge) was investigated after the initial discharge. Our results have demonstrated that the composition and structure of electrode after the charging to 3.0 V could not recover its original state of FeS2 and a new phase of NaFeS2 was revealed. This should be responsible to the large irreversible capacity in the first cycle and the high discharge and charge plateaus after the initial cycle. [Copyright &y& Elsevier]

Abstract: A typical large capacity sodium sulfur (NaS) battery is operated at 300–350 °C with 20–50 °C thermal fluctuations during its charging and discharging. In addition, for maintenance purposes, the cell experiences larger temperature changes down to the intermediate or room temperatures. Such temperature changes can cause mechanical failure of heterogeneous joints such as thermal compression bonding (TCB) joints, which is one of the most critical issues in developing NaS batteries. The present study seeks to build a computational finite element analysis (FEA) model to predict the thermomechanical responses of NaS batteries to the attack induced by the temperature changes. Specifically, the thermomechanical stress accumulation at TCB joints of a tubular cell has been explored during its booting-and-shutdown cycles. Static temperature profiles and simplified friction conditions in the cathode wall were assumed for the model. Using the developed model, the stress components that dominantly contribute the stress accumulation at the joint were identified, and the effects of TCB geometries and container material types on the thermal stress accumulation at the TCB joints were carefully examined. It turns out that the stress accumulation at the bonding interface would be critical for the failure at the TCB joints. [Copyright &y& Elsevier]