bluuebunny/crossref_metadata_2025 huggingface dataset:
New Carbon Materials with Large Closed Pore Volume for the Anode of High Energy Na-Ion Batteries
Authors: Kano Akira , Okano Tetsuyuki , Hojo Nobuhiko , Ito Shuji , Fujimoto Masahisa , Nakura Kensuke
Published: February 2020

Recently the demand for rechargeable batteries with high capacity, high power, long life, high reliability, and low cost has been increasing. While Li-ion batteries offer the highest energy density among present battery technologies, the higher cost and insufficient resources of lithium is a bottleneck to enabling their wider use. Na-ion batteries, where sodium acts as the current carrier, are attractive alternatives to Li-ion batteries because of the lower cost and abundance of sodium. However, the energy density of Na-ion batteries is still lower than that of Li-ion batteries, therefore the development of the active materials achieving a higher energy density is eagerly anticipated.

 For anode materials in Na-ion batteries, a non-graphitized carbon, such as hard carbon, is well-studied in contrast to Li-ion batteries, where graphite is usually used as the anode material. The capacity of non-graphitized carbon in Na-ion batteries is reported to be 200 - 300 mAh/g [1,2]. In Na-ion insertion process, it is proposed that Na-ions are inserted between stacked graphenes in the higher potential above ca. 0.2 V vs. Na+/Na, and then nano-pores are filled during electrochemical reaction in the lower potential region [1,2].

 In our previous research, we focused on the effect of the pore structure of carbons, and found a linear relationship between the reversible capacity in the range of 0.2 - 0 V vs. Na+/Na and the closed pore volume of non-graphitized carbons. This result suggests that Na-ion could be inserted reversibly into the closed pore of non-graphitized carbons, and thus the non-graphitized carbon with large closed pore volume is a promising anode material for higher capacity Na-ion batteries [3].

 In this study, we synthesized a new carbon material with a large closed pore volume using the carbon sources including a pore-forming agent as the starting material. It has the closed pore volume of 0.49 cc/g and its discharge capacity reached 438mAh/g.

 [1] D. A. Stevens et al, J. Electrochem. Soc., 148 (2001) A803

 [2] S.Komaba et al, ACS Appl. Mater. Interfaces, 3 (2011) 4165

 [3] A. Kano et al, 228th ECS meetings, (2015) 221
(Invited) Key Challenges Facing Rechargeable Magnesium Batteries: A Peek Outside the Box
Authors: Gregory Thomas D
Published: February 2020

Rechargeable magnesium battery science & technology has benefited from a number of advances over the past 30+ years but the still requires significant improvement before it can be considered to be a viable alternative to lithium-based batteries.  In particular, cathode materials with performance characteristics that preserve the advantages of Mg (especially its high volumetric capacity, low cost, and safety characteristics) have been elusive.  This talk will highlight the physical and chemical phenomena which contribute to these difficulties and discuss methods of circumventing them.  Electrolytes which support the unique electrochemistry of Mg have also presented R&D challenges which will be discussed.

Intercalation cathodes have received the most attention in this field but the number of materials which have been identified that can reversibly intercalate Mg2+ ions is considerably less than the number capable of reversibly intercalating Li+.  Reduced mobility and ion trapping of the more charge-dense Mg2+ions in solid structures have been identified as factors which contribute to this situation, and techniques for addressing these factors such as incorporating charge-shielding molecules including water will be discussed.  Recent promising results with polyanion intercalation and organic redox cathode materials will also be reviewed.  Conversion cathodes are seeing renewed interest in this area as a result of difficulties encountered with intercalation cathodes, but cell voltages with common conversion cathode materials such as sulfur are significantly lower than those attained with lithium.  Performance requirements for low voltage conversion cathodes which could contribute to cells with energy densities comparable to advanced lithium-ion batteries will be reviewed along with possible strategies for implementation.  Figure 1 shows active material-only specific energies which may be obtainable with possible intercalation and conversion cathodes.

Electrolytes have also proved to be challenging for rechargeable Mg batteries, and recent advances in this field will be reviewed, along with potential strategies for improving them and coupling advanced Mg electrolytes with novel cell chemistry.

References

Muldoon, J.; Bucur, C.B., Gregory, T. Quest for Nonaqueous Multivalent Secondary Batteries: Magnesium and Beyond. Chem. Rev., 2014, 114 (23), pp 11683–11720 DOI: 10.1021/cr500049y.

Bucur, C. B.; Gregory, T.; Muldoon, J. Why Grignard’s Century Old Nobel Prize Should Spark Your Curiosity. In Rechargeable Batteries; Zhang, Z., Zhang, S. S., Eds.; Green Energy and Technology; Springer International Publishing, 2015; pp 611–635.

Bucur, C.B.; Gregory, T.; Oliver, A.G.; Muldoon, J. Confession of a Magnesium Battery. J. Phys. Chem. Lett., 2015, 6 (18), pp 3578–3591 DOI: 10.1021/acs.jpclett.5b01219.

Figure 1
Organic Cathodes for Energy Storage Systems
Authors: Liao Chen , Pan Baofei , Vaughey John T. , Zhang Zhengcheng , Burrell Anthony
Published: February 2020

Redox-active organic molecules have the potential as economical and environmentally benign cathodes for lithium ion batteries. The same concept of using organic molecules as cathodes was extended to magnesium ion batteries, however, pervious work showed considerable capacity loss upon the cycling. Furthermore, no compatible electrolytes toward both anode and cathode have been demonstrated.

Her, we have focused on several organic cathode materials as cathodes, mainly for magnesium ion batteries. For example, 2,5-dimethoxy-1,4-benzoquinone (DMBQ) was reinvestigated as a cathode material with magnesium electrolytes that are capable of plating/stripping magnesium for rechargeable magnesium-ion batteries. Two electrolytes, the magnesium bis(trifluoromethylsulfonyl)imide mixed with MgCl2 in dimethoxyethane (Mg(TFSI)2-2MgCl2 in DME) electrolyte, and the Mg(TFSI)2 in diglyme were selected. The Mg(TFSI)2-2MgCl2 in DME enabled Mg-DMBQ batteries with a discharge potentials above 2.0 V vs Mg/Mg2+, which is superior to the previous reported potential in Mg-DMBQ batteries with conventional magnesium salt-based electrolytes (1.1 V vs Mg/Mg2+ ), and also excels the well-known Chevrel phase Mo6S8 in magnesium-ion batteries (1.2 V vs Mg/Mg2+).

The other organic cathodes explored for magnesium ion batteries are the redox active polymers. With emphasis on the structure motif, several polymers were investigated as high performance cathode candidates for magnesium storage. Excellent electrochemical reversibility was established for polymers within the range of 1.5-2.0 V (vs Mg), with a 99% capacity retention in 100 cycles (104.9 mAh g-1 at 100th cycle). The superior cycling stability was further demonstrated by 1000 discharge-charge cycles with very small amount of capacity loss, highlighting the great potential of redox-active organic polymer cathodes for advanced Mg-ion batteries.

Figure 1
Magnesocene-Based Electrolytes - a New Electrolyte Class for Magnesium Batteries
Authors: Schwarz Rainer Martin , Fischer Philipp , Pejic Marijana , Marinaro Mario , Jörissen Ludwig , Wachtler Mario
Published: February 2020

Technological evolution puts up an ever-growing demand on energy storage – challenging today’s technology. However, future needs for capacity, efficiency, availability and price on energy storage devices exceed the current state of the art technology, Lithium-ion, by far and require advanced alternative technologies. Currently, multiple alternatives are still undergoing research efforts. Magnesium batteries are a prime candidate to those future demands - magnesium is energy dense, 2205 mAhg-1, abundant and comparatively cheap. [1, 2]

Despite these promising properties, magnesium batteries still face major roadblocks until their commercialization. The favoured, high energy density, magnesium metal anode is, at the current state of research, only compatible with electrolytes based upon either magnesium-organo-halo-aluminates or magnesium-borohydrides. [3, 4] Electrolytes based upon conventional magnesium salts e.g. such as halides, perhalates or imides seem to be incompatible to the magnesium metal surface [5] where the electrolyte degenerates and forms a passivating, magnesium ion impermeable, surface layer.

Here, we would like to report on a new electrolyte system for magnesium batteries, based upon the bis(η5-cyclopentadienyl)-magnesium complex. The proposed electrolyte is highly suitable for a metallic magnesium anode. We will present the results of a comprehensive electrolyte-system characterisation, electrochemical performance testing (Figure 1), SEM and XRD analysis of the deposited magnesium, as well as IR and NMR studies on the fresh and cycled/aged electrolyte.

The presented work introduces a completely new electrolyte class for magnesium batteries.

Figure 1: Cyclic voltammogram of a 0.5 M MgCp2 in THF solution obtained at a scan rate of 10 mVs-1 in a potential range of -0.5 V to 1.2 V vs. Mg/Mg2+ for 500 cycles; WE: Cu, CE: Mg, RE: Mg.

References

[1] R. D. Shannon; Acta Cryst., 1976, A32, 751-767

[2] D. R. Lide (ed.); Section 14, Geophysics, Astronomy, and Acoustics; Abundance of Elements in the Earth's Crust and in the Sea, 85 ed., CRC Press, 2005.

[3] D. Aurbach, Z. Lu, A. Schechter, Y. Gofer, H. Gizbar, R. Turgeman, Y. Cohen, M. Moshkovich, E. Levi.; Nature, 2000, 407, 724

[4] Mohtadi, R., Matsui, M., Arthur, T. S. and Hwang, S.-J.; Angew. Chem. Int. Ed., 2012, 51, 9780

[5] O. Tutusaus, R. Mohtadi; ChemElectroChem, 2015, 2, 51-57

Acknowledgement

Funding is gratefully provided by BMBF - Project No.03EK3027C

Figure 1
Development of High Area Loading and Stable Sulfur Electrode through Interface Functionality and Electrode Design for Lithium Sulfur Battery
Authors: Liu Gao , Ling Min , Yang Changan , Ai Guo
Published: February 2020

High area loading of sulfur is a critical parameter to achieve high energy-density Li-S battery. Interface properties between electrode and electrolyte play an important role in these batteries. Sulfur species dissolution, precipitation and phase transformation during the charge and discharge process strongly affect the performance of lithium sulfur (Li-S) batteries. In this work, we examine the chemical functionalities and electrode structures that are important to stabilize sulfur electrode. As an example, binders with different functionalities, which differs both in chemical and electrical properties, are employed to modify the interface between the conductive matrix and electrolyte. The phase transformation of sulfur species at this interface is studied in detail. Remarkable differences are observed among sulfur cathodes with different binders modified interface. More solid-phase sulfur species precipitation is observed with binders that have strong affiliate functional groups, like poly(9, 9-dioctylfluorene-co-fluorenone-co-methylbenzoic ester) (PFM) and poly(vinylpyrrolidone) (PVP), in both fully charged and discharged states. Also, the improved conductivity from introducing conductive binders greatly promotes sulfur species precipitation. These findings suggest that the contributions from functional groups affinity and binder conductivity lead to more sulfur transformation into the solid phase, so the shuttle effect can be greatly reduced, and higher sulfur area loading and better cycling stability can be obtained.
High Energy Density Lithium-Sulfur Batteries for NASA and DoD Applications
Authors: Bugga Ratnakumar V , Jones Simon C. , Jones John-Paul , Pasalic Jasmina , Krause Frederick C. , Torres Loraine
Published: February 2020

We have been successfully using Li-ion batteries in several NASA missions since 2000, including the Mars Exploration Rovers (Spirit and Opportunity), Mars Science Laboratory (MSL), Phoenix Lander, JUNO, Aquarius, Keppler Rovers and SMAP. Being compact, lightweight and durable, these batteries have contributed to a significant enhancement or even enablement of these missions. However, NASA’s future missions, e.g., Astronaut’s Portable Life Support System (PLSS) for Extra-Vehicular Activities (EVA), small planetary rovers, planetary probes, CubeSats etc., require more advanced battery technologies with higher energy densities. The lithium-sulfur system emerges as the most promising technology, because of its high theoretical specific energy (3-4x) compared to Li-ion cells. However, despite many significant developmental efforts over the last few years, Li-S technology hasn’t matured yet, mainly due to the challenges from the soluble polysulfides forming a redox shuttle and also poisoning the lithium anode. Several attempts are being reported in the literature to develop novel cathode designs, e.g., hierarchical porous carbon structures to sequester sulfur and its reduction products, and also electrolyte solutions to minimize their solubility. 1-5 Good cycle life was reported in some of these cases with nanostructured sulfur cathodes in both organic electrolytes containing suitable additives (LiNO3) and in ionic liquids, but the sulfur loadings are much lower (below 4 mg/cm2), while high loadings of >12 mg/cm2 are essential for high specific energy Li-S cells. In this context, we have developed new sulfur composite cathodes blended with transition metal sulfides (e.g., titanium and molybdenum disulfide), which not only provided adequate electronic and ionic conductivity, but also facile electrochemical activity at sulfur reduction potentials to function as redox mediators.6 With such blended cathodes, we have been able to realize high specific capacities of ≥800 mAh/g at C/3 rates with high material loadings. In this paper, we will describe the performance of these composite sulfur cathodes in different electrolytes, and also in conjunction with a polymer-protected Li anode.

Y. Yin, S. Xin, Y. Guo and L. Wan, Angew. Chem. Int. Ed. 2013, 52, 13186 (2013).

S. Evers, L. F. Nazar, Acc. Chem. Res., 46, 1135 (2013);

X. Ji, K. T. Lee, L. F. Nazar, Nat. Mater. 8, 500 (2009).

A. Manthiram, S.-H. Chung, C. Zu, Adv. Mater. 27, 1980 (2015).

S. S. Zhang, Front. Energy Res. 1, 1 (2013).

Ratnakumar Bugga, Simon Jones, Jasmina Pasalic, Dan Addison and Ramanathan Thillaiyan, 228th ECS Meeting, Phoenix, AZ, Oct. 11 (2015)
Investigating Lithium-Sulfur-Metal Interactions in the Host Materials of Li-S Batteries
Authors: Li Zhejun , Lu Yi-Chun
Published: February 2020

Rechargeable Li-S batteries promise to provide a 2 to 3 times higher specific energy than conventional Li-ion batteries.1 The development of Li-S batteries has been strongly hindered by poor rechargeability, limited rate capability and rapid capacity fading, which largely can be attributed to the dissolution, diffusion and side reactions of soluble polysulfides in the electrolyte2. Applying host materials that can chemically bind polysulfides has been shown one of the most effective approaches in suppressing polysulfide shuttle3, which significantly improve the coulombic efficiency and the cycle life of the Li-S batteries. For instance, metal oxides such as TiO2
4, Ti4O7
5, MnO2
6have been reported effective as polysulfide immobilizers. To rationally design the host materials, it is required to understand the nature of the chemical bonding between the host materials and polysulfides and investigate key materials property that dictates the interactions.

In this work, we investigate series of transition metal oxides hosting materials for polysulfide absorption in two model electrolytes including 1,3-dioxolane (DOL):1,2-dimethoxyethane (DME) and dimethyl sulfoxide (DMSO). We apply UV-vis spectroscopy, X-ray absorption spectroscopy and X-ray photoelectron spectroscopy to understand the interactions between transition metals and various form of polysulfides (S8
2-, S6
2-, S4
2-). We further apply selected metal oxide hosting materials in Li-S batteries and characterize the effect of hosting materials in the cycling stability of Li-S batteries. We will examine the correlation between the degree of sulfur-absorption revealed by UV-vis spectroscopy and the improvement in the cycling stability of Li-S batteries. The enhancement mechanism and the nature of the bonding between the host materials and polysulfides will be discussed.

Acknowledgement:

This work is partially supported by a grant from the Research Grants Council (RGC) of the Hong Kong Special Administrative Region (HK SAR), China, under Theme-based Research Scheme through Project No. T23-407/13-N, and partially supported by a RGC project No. CUHK14200615.

Reference:

1. A. Manthiram, Y. Fu, S.-H. Chung, C. Zu and Y.-S. Su, Chem. Rev., 114, 11751 (2014).

2. M. Wild, L. O'Neill, T. Zhang, R. Purkayastha, G. Minton, M. Marinescu and G. Offer, Energy Environ. Sci., 8, 3477 (2015).

3. Q. Pang, X. Liang, C. Y. Kwok and L. F. Nazar, J. Electrochem. Soc., 162, A2567 (2015).

4. S. Evers, T. Yim and L. F. Nazar, J. Phys. Chem. C, 116, 19653 (2012).

5. Q. Pang, D. Kundu, M. Cuisinier and L. F. Nazar, Nat. Commun., 5, 4759 (2014).

6. X. Liang, C. Hart, Q. Pang, A. Garsuch, T. Weiss and L. F. Nazar, Nat. Commun., 6, 5682 (2015).
Phthalocyanines Based Two-Phase Catalysts for Lithium Oxygen Batteries
Authors: Arul Anupriya , Christy Maria , Moon Kwang Uk , Park Hyoseok , Oh Mi Young , Nahm Kee Suk
Published: February 2020

Li-air batteries, which are considered to offer much higher energy density than the current Li-ion batteries suffer from poor cycle life due to electrolyte decomposition and clogging of the air cathode by insoluble discharge products. Efficient bifunctional catalysts could improve the stability of Li-air batteries by lowering the overpotential and prolonging the battery cycle life. This study focuses on Iron phthalocyanines (FePc) as possible bifunctional electrocatalysts. Metal phthalocyanines were utilized mainly because of their structural analogy which could be fine- tuned by the metal being used, accessibility, and low cost. In this work, firstly, FePc supported on graphite nanofibres (GNF) was investigated as solid electrocatalyst in non-aqueous LiTFSI (TEGDME) electrolyte. Secondly, FePc was dissolved in the non-aqueous electrolyte and studied as liquid catalyst with GNF cathode. FePc/GNF (solid catalyst) delivered superior electrocatalytic performance for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) comparable to that of commercial Pt/C. FePc_electrolyte (liquid catalyst) exhibited a steady profile for chronoamperometry, and good diffusivity of lithium ions as measured from electrochemical impedance spectroscopy. The bifunctional catalysts when applied as electrocatalysts in non-aqueous lithium air batteries delivered better electrochemical performance mainly by reducing the large overpotential associated with ORR and OER. Both the cells with solid and soluble FePc exhibited better reversibility and cyclability. The performance of FePc catalyst as solid and liquid has been comparative analyzed in detail.
Electrochemical and Structural Characterizations of a Zinc-Ion Battery System Consisting of Zn2Mo6S8 As the Negative and Zn3[Fe(CN)6]2 As the Positive Material
Authors: Chae Munseok S , Hong Seung-Tae
Published: February 2020

The rechargeable zinc-ion batteries have received attention as candidates for large-scale energy storage systems, being expected to give high performances in terms of the cost effectiveness due to the abundance of the elements, the safety, the energy density and the environmental friendliness.[1, 2] However, zinc metal has serious dendrite problems, resulting in low stability. Using intercalation-based anode materials could be a viable way to solve such problems.

 In this work, we have constructed the prototype of such a zinc-ion battery system, employing Zn2Mo6S8 as the anode material since it intercalates zinc ions at low operating voltage of 0.35 V (vs. Zn2+/Zn),[3] and Zn3[Fe(CN)6]2 as the cathode material that also intercalates zinc ions at higher voltage of 1.75 V (vs. Zn2+/Zn) in ZnSO4 aqueous electrolytes (Fig. 1a and 1b). The negative and positive electrodes consisted of the active materials (Mo6S8 and Zn3[Fe(CN)6]2, respectively), the conductive carbon (Super P), and the binder [poly(vinylidene difluoride)] (8:1:1 w/w). The full-cell system was composed of the negative and the positive electrodes with a mass ratio of 5.5:1. The sufficiently high N/P loading ratio produced a positive-electrode limiting cell. Fig. 1b shows the discharge-charge profiles of each electrode measured with three-electrode system with zinc metal as the reference electrode. The negative electrode showed a flat profile at 0.35 V due to the high N/P ratio. The positive electrode was discharged to 1.10 V, displaying the capacity of 62.3 mAh g-1, and subsequently charged up to 2.05 V. The discharge-charge profile for the two-electrode full-cell showed a reversible cycle with the average discharge voltage at 1.40 V, demonstrating a successful zinc-ion battery system.

 Detailed analyses with ICP-OES, EDX, XRD were performed to confirm the zinc intercalation chemistry. This result should be an important basis for understanding the electrochemical intercalation reaction of zinc as well as other divalent ions into various host materials.

References

[1] C. Xu, B. Li, H. Du, F. Kang, Angew. Chem., 2012, 124, 957–959.

[2] L. Zhang, L. Chen, X. Zhou, Z. Liu, Adv. Energy Mater., 2015, 5, 1400930.

[3] M. S. Chae, J. W. Heo, S. –C. Lim, S. –T. Hong, Inorg. Chem., 2016,
55, 3294–3301.

Figure 1
Tuning Polysulfide Adsorption in Li-S Positive Electrodes with Metal Organic Frameworks.
Authors: Park Haesun , Siegel Donald J
Published: February 2020

A central problem limiting the performance of Lithium-Sulfur (Li-S) batteries is the soluble nature of polysulfide intermediates. To minimize the dissolution of polysulfides (PS) various cathode materials have been proposed. It has been argued that desirable cathodes have high surface areas and strongly adsorb polysulfides. Both of these properties are exhibited by Metal Organic Frameworks (MOFs), which are widely recognized for their ability to capture molecular species such as CO2 or methane. Although many MOFs are known, the compound known as MOF-74 is an especially attractive cathode support due to its regular porosity, high surface area (~1000m2/g), and high density of coordinately unsaturated metal sites (CUSs) which serve as binding sites for adsorbates. Here, we use first-principles computation to identify metal-substituted compositions of MOF-74, “M-MOF-74,” that maximize PS adsorption. Adsorption energies were evaluated for S8 rings, Li2S4, and Li2S across 16 metal substituted variants of M-MOF-74 (M=Be, Mg, Ca, Sr, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Sn). The most promising candidates for use as Li-S cathodes are identified, and the factors that control adsorption are discussed.
Compatibility Studies with New F-Free Electrolyte for Sodium Ion Batteries
Authors: Bitner-Michalska Anna , Trzeciak Tomasz , Poterala Marcin , Zukowska Grazyna Zofia , Niedzicki Leszek , Wieczorek Wladyslaw , Marcinek Marek
Published: February 2020

Up to now sodium battery technology finds application for high temperature systems such as sodium-sulfur and sodium-metal chloride batteries. The challenge, which we took up was synthesis and investigation of the new F-free sodium salts as a base for electrolytes working at room-temperature batteries.

While the best conductivities have been shown by fluorinated salts, there is a paradigm shift in research and development. Since fluorinated salts may negatively affect electrolyte safety, cost and environmental friendliness, some researchers are looking for fluorine-free options [1]. Even partial elimination of the salts containing fluorine (both type YFX
n-or fluoro-organic) should lead to limiting production and emissions of toxic compounds to the environment. Use of a salt which doesn’t contain fluorine has also significant advantages such as stability of the electrode-electrolyte phase boundary in batteries or lack of formation of lithium fluoride layer at the solid-electrolyte interphase.

Three novel sodium salts: sodium pentacyanopropenide, sodium 2,3,4,5-tetracyanopirolate and sodium 2,4,5-tricyanoimidazolate were dissolved in organic solvents for sodium-ion batteries electrolytes. Salts were selected with respect to their fluorine-free composition and diffused negative charges. Due to the unique, non-covalent structural configurations of anions, improved electrolyte properties were observed [2]. Excellent dissociation of salts in carbonate such as PC or mixed carbonates EC/DMC results in high conductivity at room temperature. All presented salts showed high thermal stability and suitable width of electrochemical stability windows between 3 and 5 V.

For the very first time new type of electrolyte based on F-free sodium salts were studied versus electrode materials. Their superior electrochemical properties, compared to the reference systems will be presented.

[1] Scheers, J., et al. All fluorine-free lithium battery electrolytes. J. Power Sources
251,451-458 (2014)

[2] Plewa-Marczewska, A. et al., New Tailored Sodium Salts for Battery Applications, Chem. Mater., 26 (2014), 4908–4914
Improved Performance and Fabrication of Interlayer for Advanced Lithium-Sulfur Batteries
Authors: Kim Hee Min , Manthiram Arumugam , Sun Y.-K.
Published: February 2020

In the search for next-generation energy-storage materials, the lithium-sulfur battery has drawn much attention due to its immensely high theoretical specific capacity of 1675 mAh g-1 and energy density of 2600 Wh kg-1. Its added benefit of being a low-cost, copiously available, and environmentally benign material has also prioritized the Li-S battery as an auspicious candidate. Despite such auspiciousness, the lithium-sulfur battery has inherent disadvantages that hinder its commercialization: (i) elemental sulfur and Li2S suffer from poor electrical conductivity which makes the use of high-sulfur content electrodes challenging and (ii) polysulfide migration to and reverse reaction at the negative electrode during the charge/discharge process, known as shuttle effect, result in a loss of active material and degeneration of capacity and Coulombic efficiency.

A plethora of efforts has been made to resolve these issues. A traditional approach taken by researchers is the use of sulfur mixed with, confined by, and impregnated in all kinds of carbons to augment conductivity. However, polysulfide migration still occurs and cycle life is inadequate for practical applications. Previous papers introduced the use of carbon-paper interlayers in between the sulfur cathode and the polymer separator or carbon-coated membrane and demonstrated high sulfur utilization with better cycle life due to the suppression of polysulfide diffusion to the anode and the serving of the carbon-paper interlayer as a pseudo-upper current collector.

We present here the fabrication of an interlayer consisting of MWCNT and the electrolyte in a single fabrication process. Such MWCNT-electrolyte-paper interlayers are much more effective compared to the bare MWCNT-paper interlayer due to the fast ionic and electronic transport and a better interface between the sulfur cathode and the interlayer as well as between the separator and the interlayer.
Understanding the Mechanism of Two-Step Discharge Behavior in Lithium Air Batteries with Extremely High Capacity
Authors: Kim Won Keun , Kim Jin Soo , Jin Dae Gun , Kim Ji Na , Ryu Kyoung Han , Lee Ho-Teak
Published: February 2020

A rechargeable lithium air battery holds promise as a high theoretical energy density battery system for electric vehicles. However, it requires various air management components other than the batterycells, and this can cause a significant loss in volumetric energy density.1) Many researchers often report specific capacity in the range of 1,000 ~ 3,000 mAh/gcarbon without any consideration of areal and/or volumetric capacity. Based on our estimation of system level energy density including balance of plant, the areal capacity should be around 20 mAh/cm2 for 500-mile ranged vehicle applications. On the path to higher areal capacity, we found abnormally high capacity with two distinct discharge plateaus called two-step discharge behavior as shown in Fig. 1. The first and second discharge appeared at approximately 2.6 and 2.4 V, respectively. This unknown property was frequently accompanied by limited charging capacity, which was under 50% of its full discharge capacity. Several efforts such as controlling the amount of electrolyte and oxygen flow/pressure were performed in an attempt to explain this abnormal behavior at this high discharge capacity.

 In this presentation, we demonstrate reversible lithium air battery system with extremely high capacity over 20 mAh/cm2. The product analysis after each step of reaction confirmed that the main product is crystalline Li2O2 , and partially amorphous carbonates were formed as byproduct. From the result of in-situ DEMS analysis, the two-step discharge behavior had 70% oxygen efficiency (O2_OER/O2_ORR), and clearly exhibited two electron transfer reaction during charging/discharging cycle. Further results and detailed analysis will be discussed in this presentation.

1) K. G. Gallagher et. al., Energy Environ. Sci., 2014, 7

Figure 1
Carbon Coated Mesoporous CeO2 on Graphene Foam As Flexible Cathode in Lithium-Air Batteries
Authors: Jiang Yuexing , Cheng Junfang , Zou Lu , Chi Bo
Published: February 2020

With the rapid development of foldable electronics in recent years, flexible energy storages have received extensive attention. As the key component, several prototypes such as flexible supercapacitors, li-ion batteries, and solar cells have been developed for practical application. However, low theoretical energy density of these power storages will limit their application in new flexible device. Therefore, non-aqueous lithium-air batteries have been developed for their extremely high theoretical specific energy density about 3600 Wh·kg-1, 3-5 times higher than that of the current lithium-ion batteries1, 2. When used in ambient air as flexible batteries, several problems must be overcome: (1) lithium anode should be protected from CO2 and H2O, (2) catalyst of high activity towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) should be introduced at lower oxygen partial pressure3. Thus the structure of the air cathode should be optimized. Macroporous along with mesoporous with high specific surface area should be introduced for the effective adsorption of O2 on the active sites, as well as the enhanced transportation of the reactants and intermediate species on the catalyst4. In our studies, mesoporous CeO2 microspheres were synthesized through hydrothermal process on 3D macrospores graphene foam as flexible cathode. CeO2 microspheres with the size of ~ 300 nm are distributed uniformly on the surface of 3D graphene foam with carbon coated for enhanced electrical conductivity. With the macroporous provided by 3D graphene foam for O2 diffusion and the mesoporous CeO2for enhanced catalytic activity towards ORR and OER, the LABs show better reversible capacity. And the detailed morphological and electrochemical analysis will be discussed in the presentation.

References

[1] P. G. Bruce, S. A. Freunberger, L. J. Hardwick and J. M. Tarascon, Nat. Mater., 11, 19 (2012).

[2] A. C. Luntz and B. D. McCloskey, Chem. Rev., 114, 11721 (2014).

[3] J. Yi, X. Liu, S. Guo, K. Zhu, H. Xue, H. Zhou, ACS Appl. Mater. Inter., 7, 23798 (2015).

[4] J.-J. Xu, Z.-L. Wang, D. Xu, F.-Z. Meng and X.-B. Zhang, Energy Environ. Sci., 7, 2213 (2014).
Honeycomb Compound Na3Ni2BiO6 As Positive Electrode Material for Na-Ion Battery
Authors: Zheng Lituo , Obrovac Mark N
Published: February 2020

Introduction

Layered sodium transition metal oxide materials are promising candidates as positive electrode for sodium ion batteries. Partial substitution of the transition metal with other metal could modify the crystal structure and electrochemistry of the materials. Honeycomb oxides such as Na3Ni2SbO6 have been studied and showed high energy density.1,2 In this study, honeycomb compound Na3Ni2BiO6 was synthesized and characterized in Na cells.

Experimental

Stoichiometric amounts of NiO, NaBiO3 and Na2CO3 powders were mixed by ball milling and pelletized. The pellets were heated at 700 ºC for 8 hours first then 750 ºC for 12 hours under oxygen to obtain Na3Ni2BiO6. Heated samples were transferred to Ar-filled glovebox immediately. Electrodes were made with active material, PVDF binder, carbon black at a ratio of 8:1:1 and dried under vacuum at 120 ℃ overnight. 1M NaPF6 in a solution of EC, DEC, FEC (volume ratio 3:6:1) was used as electrolyte and Na foil was used as counter/reference electrode. X-ray diffraction (XRD) patterns were measured with a Rigaku Ultima IV X-ray diffractometer equipped with a Cu anode X-ray tube and a diffracted beam monochromator.

Results and discussion

Figure 1 shows the XRD pattern of synthesized Na3Ni2BiO6. The structure resembles that of Rm α-NaFeO2 (space group 166), except for the honeycomb ordering at low angles not described by the Rm α-NaFeO2 structure (indicated by stars). The honeycomb structure is generated by the 2:1 ordering of edge sharing NiO6 and BiO6 in the a-b plane. An impurity phase of NiO was present (indicated by solid circles).

Figure 2 shows the voltage curve of Na3Ni2BiO6 for the first 2 cycles in the voltage range of 1.5 V – 3.8 V and 1.5 V – 4.5 V. Na3Ni2BiO6 was found to have a reversible capacity of ~80 mAh/g, corresponding to the reversible removal of ~0.5 Na per NaNi2/3Bi1/3O2. It should be noted that the heavy atomic weight of Bi lowers the gravimetric capacity. The voltage curve is characterized by two flat plateaus located at ~3.3 V and ~3.5 V during charging, which is typical for Ni-compounds. The two plateaus are both reversible during discharging with a hysteresis of ~0.2 V. When the cell was cycled between 1.5 V – 4.5 V, another plateau with a capacity of ~20 mAh/g appears at ~4.3 V upon charging. However this plateau is not reversible, as can be seen by the similar discharge curve to that of cycled between 1.5 V – 3.8 V. The cycling performance, rate capability and structural changes during charge/discharge will also be discussed.

Acknowledgments

The authors acknowledge funding from NSERC and 3M Canada under the auspices of the Industrial Research Chair and Discovery grant programs.

References

1. D. Yuan et al., Adv. Mater., 26, 6301-6306 (2014)

2. J. Ma et al., Chem. Mater., 27, 2387-2399 (2015)

Figure 1
{001} Facets Exposed Anatase TiO2 Nanosheets and Reduced Graphene Oxide Composite Anodes for High Performance Na-Ion Batteries
Authors: Mei Yueni , Huang Yunhui , Hu Xianluo
Published: February 2020

Lithium ion batteries (LIBs) have been widely applied in energy storage applications such as electric vehicles and portable devices, pushing up the price of lithium compounds and making lithium resources more limited. Owing to the high abundance, low cost and similar redox potential compared to lithium, sodium becomes a suitable candidate. Up to now, a variety of cathode materials have been investigated for sodium ion batteries (NIBs). However, finding suitable anode materials remains a huge challenge. Graphite, which has been employed as commercialized anode in LIBs, exhibits poor performance in NIBs (less than 35 mAh g−1). Recently, titanium dioxide (TiO2) has been proposed as anode materials for NIBs1. TiO2 has the advantages of low cost and structural stability, which hold great promise for application in NIBs.

Here, we report a composite electrode that consists of rGO and anatase TiO2 nanosheets with exposed high-energy facets as anodes for NIBs. The thin anatase nanosheets with {001} facets exposed were synthesized via a simple hydrothermal route2. The as-obtained electrode shows enhanced cycling performance and rate capability. This composite electrode exhibits a specific capacity of ~110 mAh g−1 after 500 cycles at 5C rate. Overall, anatase nanosheets/rGO composite electrode was produced and could provide a possible choice for energy storage applications.

1. C. Chen, Y. Wen, X. Hu, X. Ji, M. Yan, L. Mai, P. Hu, B. Shan and Y. Huang, Nature communications, 2015, 6, 6929.

2. C. H. Sun, X. H. Yang, J. S. Chen, Z. Li, X. W. Lou, C. Li, S. C. Smith, G. Q. Lu and H. G. Yang, Chemical communications, 2010, 46, 6129-6131.

Figure 1
Towards All Solid State Batteries Using Perovskite Solid Electrolytes
Authors: Bibienne Thomas , Alvares Pauline , Castro Laurent , Bardé Fanny , Rosciano Fabio , Dollé Mickael
Published: February 2020

Safety and environmental concerns are some of the main issues when considering lithium batteries technology. All Solid State Batteries (ASSB) may give a fundamental solution to solve those concerns. These solvent-free ASSB show major advantages: thermal stability, possibility of multicell assembly, possibility to use high potential electrode materials. We recently reported the approach to assemble ASSB in one step by Spark Plasma Sintering (SPS) using phosphate materials [1, 2]. Investigations on oxide electrolytes were considered. These electrolytes require not only being chemically stable towards electrode materials, but should also provide a good electrochemical stability over a wide potential range. Candidate materials (e.g. perovskite materials) should be relatively low cost, environmentally benign and easy to produce at an industrial scale. Several perovskite electrolytes (covering most of these requirements) were synthesized and characterized by XRD and impedance spectroscopy after sintering by SPS. Their thermal stability towards well-known electrode materials was also investigated, as well as electrodes and electrolyte interfaces using SEM and EDS. This presentation will focus on the required steps to develop ASSB using perovskite solid electrolytes.

[1] A. Aboulaich et al,Advanced Energy Materials, 1, 179-183 (2011).

[2] G. Delaizir et al, Adv. Funct.
Mat., 22, 2140-2147 (2012).
Porous Carbon Nanofibers Decorated with Cobalt Nanoparticles As Binder-Free Efficient Cathode for Lithium-Oxygen Batteries
Authors: Singhal Richa , Kalra Vibha
Published: February 2020

Rechargeable lithium-oxygen (Li-O2) batteries have received much attention because of their ultra-high theoretical energy density, about ten-times higher than that of current lithium-ion batteries.[1-4] However, the development of these batteries is still at its initial stage, owing to various technical challenges such as high overpotentials, low round-trip efficiency, poor rate capability, and low cycle life. Among various issues affecting Li-O2 battery performance, the low performance of the oxygen cathode has been identified as the dominating factor.[5, 6] The development of efficient cathode with nano-architectures, large accessible surface area, and bifunctional catalytic activity is a great challenge for high-performance lithium-air batteries.[7]

In the present study, binder-free high surface area porous carbon nanofibers modified with cobalt nanoparticles (Co-PCNF) are presented as efficient cathodes for Li-O2 batteries. The macroporous inter-connected structure of carbon nanofibers with effective dispersion of cobalt nanoparticles serve as an efficient cathode with high electrocatalytic activity. Co-PCNF demonstrated much better performance as cathodes in Li-O2 batteries, with high discharge capacity, rechargeability, and rate capability, compared to non-cobalt-carbon cathodes. Li-air cells with Co-PCNF as cathode exhibit a high initial discharge capacity of 8800 mAhg-1 at the current density of 100 mA g-1, and can be recharged for more than 50 cycles with limited discharge capacity of 500 mAh g-1. Moreover, the synergistic role of N-and F- doped carbon defects and cobalt nanoparticles leads to faster electronic transfer and stabilize carbon surface, enhancing the reversibility.

 

References:

[1] M. Armand, J.M. Tarascon, Nature, 451 (2008) 652-657.

[2] G. Girishkumar, B. McCloskey, A.C. Luntz, S. Swanson, W. Wilcke, J. Phys. Chem. Lett., 1 (2010) 2193-2203.

[3] P.G. Bruce, S.A. Freunberger, L.J. Hardwick, J.-M. Tarascon, Nat. Mater., 11 (2012) 172-172.

[4] N. Imanishi, O. Yamamoto, Materials Today, 17 (2014) 24-30.

[5] L. Mai, X. Tian, X. Xu, L. Chang, L. Xu, Chem. Rev., 114 (2014) 11828-11862.

[6] Z. Ma, X. Yuan, L. Li, Z.-F. Ma, D.P. Wilkinson, L. Zhang, J. Zhang, Energy Environ. Sci., 8 (2015) 2144-2198.

[7] J. Wang, Y. Li, X. Sun, Nano Energy, 2 (2013) 443-467.
Correctly Evaluating the Performance of Lithium-Oxygen Battery
Authors: Shen Yue
Published: February 2020

The lithium-oxygen battery (LOB) is quite a controversial topic. A lot of people believe it will have a brilliant future because it has the highest theoretic energy density. But there are also other people believing it is largely overestimated. Some papers have reported LOB cathodes with specific capacity of several thousand mAh g-1, and cycle life longer than 100 cycles. But is the state-of-art LOB really that good? We looked into the conventional limited capacity cycling tests with unlimited lithium anode, and found the testing result may be misleading due to the following reasons:

1. The electrochemically active reactant at the cathode side is oxygen, which is unlimited. The active material at the anode side is lithium, also unlimited. In such a test, we are actually testing the reusability of the catalyst instead of the cyclability of the active electrode material.

2. The LOB cathode discharge and charge is accompanied with irreversible formation of side-products such as LiOH, Li2CO3, HCOOLi, Li2SO4, et al. But as long as these side-products are dissolved or simply accumulated away from the cathode and do not hinder the discharge, the cycling can still go on.

3. The cathode/electrolyte weight ratio is usually extremely small, which makes the cathodic weight based specific capacity meaningless.

Because of the above reasons, we propose a novel Li2O2-graphite set-up to evaluate the cathodic cyclability. Unlike the conventional set-up with unlimited lithium metal anode, the total amount of lithium ion in the Li2O2-graphite battery is limited. If any side reactions consumed the lithium-ion, the capacity lose would be objectively reflected to the charge/discharge curves. Based on this set-up, several electrolyte recipes were compared and we found the positive effect of redox mediates to improve the cycling performance is very obvious. On the whole, the LOB still has a future, but we must face the challenge before overcome it.
Lithium Halides As Redox Mediators in Lithium Oxygen Battery
Authors: Kwak Won-Jin , Hirshberg Daniel , Sharon Daniel , Afri Michal , Frimer Aryeh A , Aurbach Doron , Sun Yang-Kook
Published: February 2020

In case of soluble electrolyte catalysts for Li-O2 batteries as a redox mediator, they were utilized to facilitate the exchange of electron and lithium ion, which can help formation and decomposition of discharge product. Although further researches are needed for finding proper catalysts, there is a promising approach fortunately, using lithium halides as a redox mediator in Li-O2 batteries.

Related researches have been progressed vigorously. Previous paper reported in our group demonstrated the reaction mechanism and effect of the lithium iodide (LiI) in Li-O2 battery.1 Lim et al. exhibited the superior performance of Li-O2 battery using LiI additive.2 Recently, Liu et al. developed this concept and exhibited Li-O2 battery having better performance with LiOH as a discharge product by adapting more advanced electrodes.3 However, further research with LiI is necessary for clear comprehension because there is no accurate elucidation on the reaction mechanism which can be activated gradationally in Li-O2 battery system yet.

Therefore, here in, we has progressed comparing and contrasting researches using LiI and lithium bromide (LiBr) for clearly understanding the role of lithium halide materials in Li-O2 battery system. As a redox mediator, LiBr catalyzes the reversible formation and decomposition of lithium peroxide (Li2O2), but hygroscopic LiI generated the side reaction making lithium hydroxide (LiOH) as a byproduct. Especially, when Li-O2 batteries are operated with LiBr and LiI until enough amount of capacities for practical using, LiOH made by LiI included electrolyte couldn’t be reversible compared to Li2O2 made by LiBr included electrolyte. Therefore, in our research, LiBr is much reliable redox mediator to operate the Li-O2 battery system.

References

Kwak, W.-J. et al.
J. Mater. Chem. A
3, 8855–8864 (2015).

Lim, H. et al.
Angew. Chem. Int. Ed. Engl.
53, 3926–31 (2014)

T. Liu. et al.
Science, 350, 6260, 530-533 (2015).
Printable Hecl Electrode Materials for Disposable Bioaffinity Assay Cartridges
Authors: Kulmala Sakari , Salminen Kalle , Kuosmanen Päivi
Published: February 2020

We have demonstrated earlier that hot electrons can be injected into aqueous electrolyte solution from thin insulating film coated cathodes [1, 2]. Insulating film have typically been fabricated from an insulator material with a band gap of ca. 5 eV or preferably higher, with the Fermi level of the insulator somewhere in the mid band gap region. The hot electrons are emitted to aqueous electrolyte solution by direct field-assisted tunneling at these devices [2, 3]. After injection into the conduction band of water the hot electrons are thermalized and solvated to form hydrated electrons which finally act as reducing mediators in the Hot Electron-induced Electrochemiluminescence (HECL) systems. HECL is utilized mainly in immunoanalysis and in DNA-probe assays in which electrochemiluminescent labels are utilized [ 2 - 5 ]. Best labels are certain aromatic lanthanide chelates which allow sensitive time-resolved HECL detection of the labels [3, 6].

Silicon electrodes or silicon chips on which the working electrode/electrodes and counter electrode have been integrated have been shown to be excellent functional components of disposable assay cartridges [5,7]. Recently, we have been able to develop printable HECL electrode materials that show almost equal performance and are based on conductor particles embedded in polystyrene or in some other organic insulating materials.

 

References

[1] S. Kulmala, A. Kulmala, T. Ala-Kleme, J. Pihlaja, Primary cathodic steps of electrogenerated chemiluminescence of lanthanide(III) chelates at oxide-covered aluminum electrodes in aqueous solution, Anal. Chim. Acta. 367 (1998) 17–31.

[2] S. Kulmala, H. Joela, T. Ala-Kleme A. Kulmala, Hot electron injection into aqueous electrolyte solution from thin insulating film-coated electrodes, J. Radioanal and Nucl. Chem. 232 (1998) 91-95.

[3] J. Suomi, S. Kulmala, Hot Electron-Induced Electrogenerated Chemiluminescence, in: Rev. Fluoresc. 2009, 2011: pp. 47–73.

[4] T. Ala-Kleme, P. Makinen, T. Ylinen, L. Vare, S. Kulmala, P. Ihalainen, Rapid electrochemiluminoimmunoassay of human C-reactive protein at planar disposable oxide-coated silicon electrodes, Anal. Chem. 78 (2006) 82–88.

[5] T. Ylinen-Hinkka, a. J. Niskanen, S. Franssila, S. Kulmala, Immunoassay of C-reactive protein by hot electron induced electrochemiluminescence using integrated electrodes with hydrophobic sample confinement, Anal. Chim. Acta. 702 (2011) 45–49.

[6] S. Kulmala, T. Ala-Kleme, J. Suomi, Electrochemiluminescence of Lanthanides, in: Springer Series, Lanthan. Lumin., 2011: pp. 343–360.

[7] A.J. Niskanen, T. Ylinen-Hinkka, M. Pusa, S. Kulmala, S. Franssila, Integrated microelectrode hot electron electrochemiluminescent sensor for microfluidic applications, Sens. 152 (2011) 56–62.