bluuebunny/crossref_metadata_2025 huggingface dataset:
A High-Energy-Density and Long-Life Chalcogenide-Iodide Redox Flow Battery
Authors: Li Zhejun , Lu Yi-Chun
Published: February 2020

Redox flow batteries (RFBs) are promising technologies for application in both grid-scale power station and electric vehicles owing to their flexible architecture decoupling power and energy1, 2. The development of aqueous RFBs has been strongly hindered by low energy density, limited cell voltage and rapid capacity fading, which largely can be attributed to the poor solubility of electroactive species, small voltage window of water and limited ion selectivity capability of membrane1. Chalcogenide has been reported to have high solubility in nonaqueous environment with high charge/discharge reversibility, which makes it a promising anolyte candidate for aqueous RFBs3-5. However, it is found that these sulfur-based RFBs have been challenged by their poor cycle life and rate capability, owing to the strong shuttle phenomenon and slow kinetics of polysulfide reaction3, 5. It is critical to manipulate the competition between diffusion/crossover and the rate of electrochemical reaction of soluble active species in order to improve cycle life of RFBs.

In this work, we exploited a composite-based ion-exchange membrane for chalcogenide-iodide RFBs. We evaluated the effectiveness of various membrane compositions and will discuss the role of each component in the membrane toward long-life operation. We applied UV-vis spectroscopy to probe the active reaction species involved in the RFB operation. In addition, we will discuss the use of complexing agent for polysulfide species to increase the energy density (molar electron number per molecule) and energy efficiency (higher reaction kinetics) of the chalcogenide-iodide RFBs.

Acknowledgement:

This work was fully supported by a grant from the Research Grant Council of the Hong Kong Special Administrative Region, China under NSFC/RGC Joint Research Scheme 2018/19 Project No. N_CUHK435/18.

Reference:

W. Wang, Q. Luo, B. Li, X. Wei, L. Li and Z. Yang, Adv. Funct. Mater., 23, 970-986 (2013).

F. Pan and Q. Wang, Molecules, 20, 20499-20517 (2015).

S. Yun, S. H. Park, J. S. Yeon, J. Park, M. Jana, J. Suk and H. S. Park, Adv. Funct. Mater., 1707593 (2018).

N. Li, Z. Weng, Y. Wang, F. Li, H.-M. Cheng and H. Zhou, Energy Environ. Sci., 7, 3307-3312 (2014).

Z. Li, G. Weng, Q. Zou, G. Cong and Y.-C. Lu, Nano energy, 30, 283-292 (2016).
Aging Study of the Lithium Metal Batteries Using Nickel-Rich Cathode Materials
Authors: Badillo Jimenez Juan Pablo , Börner Markus , Beuse Thomas , Schappacher Falko , Winter Martin
Published: February 2020

The lithium ion battery (LIB) is the most important energy storage device since the last decade, which is due to the excellent characteristics of operating voltage, cycle life and its low self-discharge rate. [1]. Nevertheless lithium ion batteries are gradually reaching their theoretical limits, in terms of energy density, power density as wells as durability and cost [2, 3]. Because electronic portables devices as wells as electric vehicles demand high energy density batteries, the development of next generation batteries has strongly increased during the recent years. To achieve high energy densities in these systems, lithium is used as anode due to its outstanding properties regarding the theoretical specific capacity (3860 mAh g-1) and the negative electrochemical potential (-3.04V vs. standard hydrogen electrode). However, the rapid degradation as well as safety issues related to the morphological transformation from dense to porous lithium metal affect the cell performance [4-7].

In this work, we studied the influence of the test conditions on the morphological changes on the lithium anode and cycle life of the lithium metal battery (LMB). For this, we carried out ex-situ measurements for a better understanding of the morphological changes of the anode material. Depending on the applied conditions, the cycle life of the system was improved with lower capacity fading and at the same time the morphological changes of the lithium anode were suppressed.

In the second part, the investigation is focused into the degradation of different nickel-rich cathode materials. Most of the studies on lithium metal batteries are based on the degradation of the lithium anode, however, here; it could be shown that aging of the cathode material is an important part for the development of the LMB. The results showed a good cycle performance over 300 cycles with relative low capacity fading of the LMB with all the implemented cathodes. The electrochemical data analysis showed the degradation of the cathode material, controlling at the same time the morphological changes of the lithium anode.

Literature

[1] J. Ma, B. Chen, L. Wang, G. Cui, J. Power Sources, 392, 94 (2018)

[2] H. Hao, X. Cheng. Z. Liu, F. Zhao, Energy Pol., 108, 355 (2017)

[3] A. Mahmoudzadeh Andwari, A. Pesiridis, S. Rajoo, R. Martinez-Botas, V. Esfahanian, Renew. Sustain. Energy Rev., 78, 414 (2017)

[4] D. Lu, Y. Shao, T. Lozano, W. D. Bennett, G. L. Graff, B. Polzin, J. Zhang, M. H. Engelhard, N. T. Saenz, W.A. Henderson, P. Bhattecharya, J. Liu, J. Xiao, Adv. Energy Mater., 5, 1400993 (2015)

[5] K. Xu, Chem. Rev.,
104, 4303 (2004)

[6] D. Aurbach, E. Zinigrad, Y. Cohen, H. Teller, Solid State Ionics,
148, 405 (2002)

[7] J. B. Goodenough, Y. Kim, Chem. Mater.,
22, 587 (2010)

Figure 1
(Invited) Designing Highly Stable Sodium Metal Anodes for Sodium Batteries
Authors: Li Weiyang
Published: February 2020

Sodium (Na) metal holds great promise as an anode material for next-generation energy storage systems because of its high theoretical specific capacity, low electrochemical potential, low cost and high natural abundance. Nevertheless, the implementation of Na metal anode is still largely hindered by a number of long-lasting challenges, namely metallic Na dendrite growth and unstable solid electrolyte interphase (SEI) formation. To overcome these challenges, here we present a series of versatile tactical tunings on the Na metal anode, including manipulating the Na nucleation/growth behavior, modifying the electrode-electrolyte interface, and controlling the electrode structures, to realize highly stable and dendrite-free Na metal anodes over a wide current range and long-term cycling. Coupled with different Na cathode materials, the full cells using these regulated Na metal anodes exhibit superior electrochemical performances compared to those using commercial Na metals. More importantly, we found that despite the many similarities in the chemical and physical properties of lithium (Li) and Na, the strategy that was able to stabilize Li metal could not be directly applied to Na metal, but requires more meticulous investigations, thus providing new insights into understanding the differences between Li and Na systems.
Programming the Knowledge: A Trial QSAR Study Towards the Stability of Dialkoxy Benzene Based Catholyte Molecules for Nonaqueous Redox Flow Batteries
Authors: Zhang Lu , Zhang Jingjing , Silcox Benjamin , Shkrob Ilya A , Assary Rajeev , Cheng Lei , Thompson Levi
Published: February 2020

Programming the knowledge: A trial QSAR study towards the stability of dialkoxy benzene based catholyte molecules for nonaqueous redox flow batteries

Lu Zhang1, Jingjing Zhang1, Benjamin Silcox3, Illya A. Shkrob1, Rajeev S. Assary2, Lei Cheng2, Levi Thompson4

1Chemical Sciences and Engineering Division, 2Material Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, United States

3Chemical Engineering, University of Michigan, 500 S State St, Ann Arbor, MI 48109, United States

4Department of Chemical and Biomolecular Engineering, University of Delaware,Newark, DE 19716, Unite States

The stability of redox active molecules is a paramount property that dramatically affects the cycling performance in redox flow batteries. Computationally, it requires huge amount of resource to exhaustively iterate all the possible degradation pathways in order to estimate the stability of active species, such as radical cations.1 QSAR, or quantitative structure–activity relationship, provides an interesting approach to correlate chemical structures and properties based on the idea of property changes are all coming from structure modifications. While this approach simplified the insightful analysis of the detailed mechanism, it becomes particular useful to simulate or even predict complex properties, such as the stability of redox molecules. In this talk, we developed a series of dialkoxy benzene based catholyte molecules that are of potential use to nonaqueous redox flow batteries and systematically changed their substitutions on the alkoxy moieties. Then their electrochemical/chemical properties, including redox potential, charged state stability (reflected by EPR life time), and even cycling numbers, have been characterized and analyzed. Importantly, a number of descriptors have been identified based on our long accumulated knowledge regarding stability of the charged radical cations. Finally, a linear regression model was established using those descriptors to simulate the EPR life time, and even cycling numbers and the resulted fittings delivered quite satisfactory correlation between the selected descriptors and properties. While this is only a trial study based on a small set of molecules, the QSAR approach proves to be useful in understanding complex properties for redox active molecules, which could stimulate further understanding and development of such promising materials.

Assary, R. S.; Zhang, L.; Huang, J.; Curtiss, L. A., Molecular Level Understanding of the Factors Affecting the Stability of Dimethoxy Benzene Catholyte Candidates from First-Principles Investigations. The Journal of Physical Chemistry C
2016,
120 (27), 14531-14538.
Aqueous Flow Batteries Utilizing Redox-Active Organic Molecules: Phenazine Derivatives As a Promising Anolyte Material
Authors: Hollas Aaron , Feng Ruozhu , Wellala Nadeesha , Murugesan Vijayakumar , Nie Zimin , Thomsen Ed , Shao Yuyan , Wang Wei , Reed David , Sprenkle Vincent
Published: February 2020

Redox flow batteries have gained increased attention for grid energy storage. The decoupling of power and energy between stack and electrolyte tanks offers tunability to system parameters and, when based on an aqueous electrolyte, offers a level of safety not available in traditional lithium ion batteries. The current state-of-the-art aqueous flow battery is the vanadium redox flow battery. While this system possesses desirable features of high solubility, high cell voltage, and long cycling life, the high cost of vanadium has prevented wide-scale deployment. Redox-active organic molecules have emerged as a promising alternative to vanadium. Systems based on organics offer significant synthetic tunability to optimize critical design parameters of solubility, cell voltage, and cycle life. If derived from low-cost commodity chemicals, organic systems offer a pathway to lower-cost flow battery electrolytes. Presented will be our investigation of phenazine-based anolyte species. Our approach toward molecular functionalization will be detailed, which has yielded systems that offer beyond 2e- equivalent concentrations and high cell voltages up to 1.4 V when coupled with a ferricyanide catholyte.
Zinc Anode Design for Rechargeable Aqueous High-Energy Zn Batteries
Authors: Zhang Yamin , Wu Yutong , Yan Yu , Zhou Zhubo , Liu Nian
Published: February 2020

As an energy storage system, Li-ion batteries are not safe because they use flammable organic electrolytes. A safer alternative is rechargeable Zn-based batteries with aqueous electrolytes. Among them, Zn-air batteries have high theoretical volumetric energy density (4400 Wh/L), which can even compete with lithium-sulfur batteries. Alkaline electrolyte is preferable for Zn-air batteries. However, the performance of Zn anodes in alkaline electrolyte is limited by passivation, dissolution and hydrogen evolution. Through SEM investigation, critical passivation size was found to be ~ 2 µm. Sub-micron-sized Zn anodes won’t have passivation problem. As a result, we focus our research on nanoscale. However, Zn dissolution of nanosized anodes will be accelerated because of large electrode-electrolyte surface area.

Thus, anode modification and protection are needed to alleviate the dissolution. We designed a (1) Zn mesh@GO anode (Fig. 1a): graphene oxide (GO) layers on the Zn mesh surface deliver electrons across insulating ZnO and can slow down the Zn dissolution; (2) lasagna-inspired ZnO@GO anode (Fig. 1b): ZnO nanoparticles encapsulated by GO can solve simultaneously the passivation and dissolution problems; (3) core-shell ZnO@TiN nanorod anode (Fig. 1c): thin and conformal TiN coating mitigates Zn dissolution, mechanically maintains the nanostructure, and delivers electron to nanorods. These coatings are ion selective, which allow permeation of OH- and water, and prevents loss of Zn active material through blocking bigger Zn(OH)4
2-.

Hydrogen evolution is a competitive side reaction on the zinc anodes, which causes low efficiency of Zn based batteries. Two approaches are investigated to suppress hydrogen evolution, including (1) modify the anode with a hydrogen suppressive material: core-shell ZnO@TiO2 nanorod anode was made with hydrogen suppressive TiO2 coating, which solves hydrogen evolution, passivation and dissolution problems at the same time; (2) design a hydrogen evolution suppressive nanostructured alloy anode: Zn-Ag alloy with increased standard reduction potential was used, which is more competitive compared with hydrogen evolution and more stable in aqueous electrolyte.

All of these anodes show superior performance compared with unmodified anodes. These anodes can be paired with air cathodes to make high energy Zn-air batteries. The nanoscale design principles here can potentially be applied to overcome intrinsic limitations of other battery materials.

Figure 1
Determining Interphase Identity and Directing Cation Transport Properties at Mg and Ca Electrodes
Authors: Zavadil Kevin R , Hahn Nathan T , Feng Xuefei , Liu Yi-Sheng , Guo Jinghua
Published: February 2020

Regulating cation transmission at electrode interfaces is an essential function required for realizing storage based on multivalent working ions, including Mg and Ca. Cation transmission regulating interphases are believed to exist at both anode and cathodes surfaces for a host of electrolytes based on ethereal solvents, contributing to energetic barriers to cation accommodation at metal deposits and (de)insertion into cathodes. These interphases are derived from supporting electrolyte anion, solvent or impurity decomposition or more complex synergistic reactions. Weakly coordinating anions, of defined reductive/oxidative stability in highly purified form, provide an opportunity to explore the origin and consequences of reactivity and interphase formation. In this presentation, we describe several examples where origin of reactivity has been successfully probed through electrolyte constituent control and application of operando (e.g., electrochemical X-ray absorption) and ex situ (e.g., analytical transmission electron microscopy) methods. Results highlight critical phases and distributions responsible for cation transport and provide new insight into directing interphase formation to facilitate cation transport enhancing electrode performance.

This work was supported as part of the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525.
Going Beyond Intercalation Capacity of Aqueous Metallic Zn-Anode Batteries
Authors: Yadav Gautam Ganapati
Published: February 2020

Research interest on zinc (Zn)-anode aqueous-based batteries have renewed recently because of its low equilibrium potential in aqueous electrolyte, low cost, non-toxic and nonflammable characteristics compared to lithium-ion batteries. Zn has a high theoretical capacity of 820mAh/g based on two electron reactions, thus it has the capacity to deliver high energy density if it is paired with an equally high capacity cathode. Silver and nickel are high capacity cathodes; however, they are very expensive and require the addition of expensive additives like cobalt in nickel to increase the rate of the battery. MnO2 is the best cathode to be paired with Zn because it has a high two electron capacity of 617mAh/g and it is extremely safe and economical. Recently, we showed that attaining the two electron capacity of 617mAh/g for over 3000 cycles was possible with the used of bismuth and copper additives. Energy densities >160Wh/L were attainable when the cathodes were paired with Zn at 15% utilization.1-5 However, they are still susceptible to Zn poisoning which lead to the formation of inactive phase called haeterolite (ZnMn2O4). To improve the energy densities of Zn-anode batteries new inexpensive and safe cathodes with higher capacity than MnO2 and increasing Zn utilizations to >20-25% are a must.

In this presentation, we will report the synthesis of a new Mn-based cathode that delivers capacity ~800mAh/g, which is almost comparable to the Zn anode theoretical capacity. This new Mn-based cathode is able to deliver its capacity at high rates and maintain its capacity at high cycle life. We will present the reaction mechanism of this Mn-based cathode through real time microscopy videos and images, high resolution transmission microscopy and electroanalytical methods. We also report on the use of new Zn-based anodes that utilize >90% of its theoretical capacity and, at the time of this writing, still cycle with much deterioration in capacity due to shape change or passivation. The combination of the new high capacity Mn-based cathode and high utilization Zn-based anode results in a cell that delivers energy density >210Wh/L.

References:

1] Gallaway, J. W.; Hertzberg, B. J.; Zhong, Z.; Croft, M.; Turney, D. E.; Yadav, G. G.; Steingart, D. A; Erdonmez; C. K.; Banerjee, S. Journal of Power Sources, 2016, 321, 135-142

2] Huang, J.; Yadav, G. G.; Gallaway, J. W.; Wei, X.; Nyce, M.; Banerjee, S., Electrochemistry Communications, 2017, 81, 136-140

3] Yadav, G. G.; Gallaway, J. W.; Turney, D. E.; Nyce, M.; Huang, J.; Wei, X.; Banerjee, S., Nat. Commun., 2017, 8, 14424

4] Yadav, G. G.; Wei, X.; Huang, J.; Gallaway, J. W.; Turney, D. E.; Nyce, M.; Secor, J.; Banerjee, S., J. Mater. Chem. A, 2017, 5 (30), 15845-15854

5] Yadav, G. G.; Wei, X.; Gallaway, J. W.; Chaudhry, Z.; Shin, A.; Huang, J.; Yakobov, R.; Nyce, M.; Vanderklaauw, N.; Banerjee, S. Materials Today Energy, 2017, 6, 198-210.
(Invited) Pushing the Capacity of Layered Oxide Cathode to the Limit
Authors: Yang Lufeng , Li Xiang , Xiong Shan , Hu Yan-Yan , Chen Hailong
Published: February 2020

Na-ion batteries are being extensively investigated as one of the possible alternatives to very popular Li-ion batteries. Compared with Li-ion batteries, Na-ion batteries have the advantage in cost, because of the much higher natural abundance and availability of Na than Li, which makes Na-ion batteries potentially a candidate for gird level energy storage. However, currently the energy density of Na-ion batteries is in general lower than those of Li-ion batteries, limited by multiple components in the cell, majorly by the cathode. Currently, most high capacity cathodes for Na-ion batteries are layered oxides with a general formula NaxMO2, where M is a transition metal or the combination of transition metals. Most of the layered oxide cathodes, however, can only stably cycle at <50% of their theoretical capacities, which greatly limits the energy density of the full cell.[1, 2] What is the limit of energy density of Na-ion batteries in current configuration? How to push the capacity of layered oxide cathodes to its theoretical limit? These are the questions to be addressed towards the goals of using Na-ion batteries to replace Li-ion batteries. In this work, we explored the fundamental reasons that limit the reversible capacity of layered oxide cathodes and demonstrated a new strategy to push their capacity to the limit, with using a group of rationally designed compounds as examples. A series of oxides, including Na0.66(Li0.2Mn0.2)O2 [3] and Na0.66Li0.18Fe0.12Mn0.7O2, etc. were designed to verify the proposed strategies and these compounds were successfully synthesized in desired P2 type layered structures. Many of these compounds demonstrated high cycling capacities ranging from 190 to 230 mAh/g, which are very close to the theoretical limit. In-depth structure characterizations with using in situ and ex situ synchrotron X-ray diffraction, neutron diffraction and solid state NMR were performed, in order to reveal the functioning mechanism of these compounds and provide more guidance to the materials design to further improve the capacity, voltage and cycling stability of the cathode materials.

[1] B.L. Ellis, L.F. Nazar, Sodium and sodium-ion energy storage batteries, Current Opinion in Solid State & Materials Science, 16 (2012) 168-177.

[2] S.P. Ong, V.L. Chevrier, G. Hautier, A. Jain, C. Moore, S. Kim, X.H. Ma, G. Ceder, Voltage, stability and diffusion barrier differences between sodium-ion and lithium-ion intercalation materials, Energy & Environmental Science, 4 (2011) 3680-3688.

[3] L.F. Yang, X. Li, X.T. Ma, S. Xiong, P. Liu, Y.Z. Tang, S. Cheng, Y.Y. Hu, M.L. Liu, H.L. Chen, Design of high-performance cathode materials with single-phase pathway for sodium ion batteries: A study on P2-Na-x(LiyMn1-y)O-2 compounds, J. Power Sources, 381 (2018) 171-180.
Liquid Structure and Battery Application of Highly Concentrated Sulfolane-Based Sodium Electrolytes
Authors: Okamoto Yukihiro , Tsuzuki Seiji , Ueno Kazuhide , Dokko Kaoru , Watanabe Masayoshi
Published: February 2020

Sodium is earth-abundant compared to lithium, and sodium ion battery has drawn much attention as an alternative battery system. We report here the physicochemical properties, solvation structure, and electrochemical properties of highly concentrated electrolytes composed of NaN(SO2F)2 (NaFSA) and sulfolane (SL) solvent for Na-ion batteries. Our group recently reported that highly concentrated Li electrolytes of SL show Li ion hopping conduction.1 In the highly concentrated lithium salt (LiX)/SL electrolytes, two oxygen atoms of SL were found to coordinate to different Li ions, forming extended chain-like Li ion coordination structures of -SL-Li+-SL- and -X--Li+-X--. In the highly concentrated electrolytes, Li ion exchanges ligands (solvent and anion), leading to the hopping-like Li ion conduction. The ionic size of Na+ is larger than that of Li+, and the Na+ ion has lower charge density compared with Li+. In this study, the effects of cation size on the physicochemical and electrochemical properties of SL-based electrolytes were investigated. We found that NaFSA and SL form a stable solvate at a molar ratio of 1:3. In the single crystal of NaFSA/SL = 1/3, two oxygen atoms of SO2 moiety of SL coordinate to two different Na ions. In addition, an oxygen atom of one SO2 moiety of FSA anion and an oxygen atom of another SO2 moiety coordinate to different Na ions as shown in Figure. At molar ratio of [NaFSA]/[SL] ≥ 1/1.6, the mixtures become glass forming liquids and keep liquid state at room temperature. Raman spectra for the liquids of [NaFSA]/[SL] ≥ 1/1.6 suggest that solvent-bridged structure (-SL-Na+-SL-) and anion-bridged structure (-FSA--Na+-FSA--) are formed even in the liquid state. Walden plot for [NaFSA]/[SL] ≥ 1/1.6 indicated that the ion conduction partially decoupled from the viscosity of the liquid. Molecular dynamics simulation suggested that Na+ ion diffuses faster than SL in the concentrated electrolytes. Battery tests of Na/hard carbon and Na/Na0.44MnO2 cells were carried out using an electrolyte of [NaFSA]/[SL] = 1/1. The cells showed stable charge-discharge behaviors, suggesting that the highly concentrated NaFSA/SL electrolyte possesses a wide electrochemical window and a potential application in Na-ion batteries.

Reference

1. Dokko, K.; Watanabe, D.; Ugata, Y.; Thomas, M. L.; Tsuzuki, S.; Shinoda, W.; Hashimoto, K.; Ueno, K.; Umebayashi, Y.; Watanabe, M. Direct Evidence for Li Ion Hopping Conduction in Highly Concentrated Sulfolane-Based Liquid Electrolytes. J. Phys. Chem. B
2018, 122 (47), 10736–10745.

Figure caption

Figure. Crystal structure of NaFSA/SL = 1/3.

Figure 1
(Invited) Carbon Fiber-Paper–Supported Carbon Nanofoams As Free-Standing Electrode Architectures for Reversible Sodium-Ion Storage
Authors: Long Jeffrey W. , DeBlock Ryan , Sassin Megan B. , Rolison Debra R. , Hoffmaster Ashley , Ko Jesse S.
Published: February 2020

Hard (non-graphitizable) carbon has emerged as a prospective charge-storage material for negative electrodes in sodium-ion batteries, yet reported electrochemical performance across this broad category of carbons varies widely. Such discrepancies arise in part due to the multiple distinct sodiation reactions that are possible with disordered carbon electrodes, whereby sodium ions can be stored in defect sites, graphitic layers, and/or micropores depending on the pore–solid architecture, surface chemistry, and solid-state structure of a particular carbon. To address both fundamental questions and practical application in Na-ion batteries, we are investigating carbon nanofoam papers (CNFPs), synthesized by infiltrating the voids of carbon-fiber paper with resorcinol–formaldehyde (R–F) formulations to form porous polymer nanofoam that is subsequently converted to the conductive carbon analog via pyrolysis at 1000°C [1]. When tested as free-standing electrode architectures in Na-ion cells, CNFPs deliver specific capacity >300 mAh g–1 at a 1C rate and >250 mAh g–1 at 10C, with a first-cycle Coulombic efficiency near 85% under galvanostatic operation. The galvanostatic intermittent titration technique (GITT) confirms that Na-ion diffusion is facile in the defect-mediated charge-storage regime. We attribute these favorable properties to the high defect concentration in the disordered R–F-derived carbon domains, the 3D-interconnected porosity within the carbon nanofoam, and the absence of otherwise-necessary binder and conductive additives that are commonly used in conventional powder-composite electrodes. Our results demonstrate the utility of CNFPs as device-ready, self-supported electrodes and advance the design of related carbon materials for next-generation Na-ion batteries.

[1] J.C. Lytle, J.M. Wallace, M.B. Sassin, A.J. Barrow, J.W. Long, J.L. Dysart, C.H. Renninger, M.P. Saunders, N.L. Brandell, and D.R. Rolison, Energy Environ. Sci., 4 (2011) 1913–1925.
Structural Evolution of Solid-State Li2O2 with Reduced Charge Overpotential in Li−O2 Batteries
Authors: Tan Guoqiang , Lu Jun , Chong Lina , Wen Jianguo , Ma Lu , Yuan Yifei , Zeng Xiaoqiao , Li Tao , Wu Tianpin , Liu Cong , Liu Di-Jia , Amine Khalil
Published: February 2020

Reducing charge-discharge overpotential is helpful to enhance efficiency and cyclability of Li−O2 batteries. In a common non-aqueous Li−O2 cell, the overpotential is largely related to the formation and decomposition processes of solid-state Li2O2. Although several intrinsic properties of Li2O2 have been considered to contribute to the high overpotential, such as the low electrical conductivity, slow dynamics, large particle aggregations, and side-reaction products, et.al,1-4 a fundamental study of specific relationship between overpotential and electrochemical reactions associating with structural evolution of Li2O2 has yet to be undertaken. Besides, the underlying mechanism of the oxygen evolution reaction on charge remains less understood.

To address the above problems, in this work, we proposed a Pt modification strategy to tune cathode architectural to optimize catalytic and electrical properties as well as electrode dynamics. We employed two different approaches of magnetron sputtering and thermal reduction to realize the Pt surface-coating and bulk-doping, respectively. Both could significantly reduce the charge overpotentials of Li−O2 cells with a higher performance from the bulk-doped catalyst. Meanwhile, systematic studies showed an unprecedented relevancy between overpotential and structural evolution of Li2O2, and the Pt nano-composition in the cathode was found to directly affect the formation and decomposition mechanism of Li2O2. Furthermore, we carried out the density functional theory calculations that provided molecular insights into the catalytic role of Pt and Pt3Co nanocrystals (resulting from surface-coating and bulk-coating, respectively) in reducing the charge overpotential.

As a result, the nanoscale bulk-doping approach was demonstrated to be a promising strategy to address the insufficient catalytic and electrical properties and sluggish electrode dynamics of oxygen cathodes for Li−O2 batteries. The exclusive insight into structural evolution of Li2O2 with the reduced charge-discharge overpotential could afford favorable theoretical investigates for further explorations on cathode materials.

Figure 1 Electrochemical discharge/charge profile and corresponding formation and decomposition mechanism of Li2O2 for the Pt bulk-doping catalyst.

References

1 Freunberger S A, et al. Reactions in the rechargeable lithium–O2 battery with alkyl carbonate electrolytes. J.
Am. Chem. Soc., 2011, 133, 8040-8047.

2 Thotiyl M M O, et al. A stable cathode for the aprotic Li–O2 battery. Nat. Mater., 2013, 12, 1050-1056.

3 Chen Y, et al. Charging a Li–O2 battery using a redox mediator. Nat.
Chem., 2013, 5, 489-494.

4 Lim H-D, et al. Rational design of redox mediators for advanced Li–O2 batteries. Nat.
Energy, 2016, 1, 16066.

Figure 1
Exploring the Effect of Varying Reduced Graphene Oxide Content on the Stable Electrochemical Performance of Sb Nanoparticles Anode for Na-Ion Batteries
Authors: Dashairya Love , Das Debasish , Majumder Subhasish B , Saha Partha
Published: February 2020

Secondary batteries have wide applications ranging from portable electronics to hybrid electric vehicles owing to increasing demand around the world for higher capacity and longer life. In this regard, metal-based anodes (Sb, Sn, etc.) are considered the material of choice, offering higher gravimetric capacity albeit with rapid fade, owing to detachment of the active material from the current collector associated with volumetric strain during repeated galvanostatic cycling. In the present work, we successfully demonstrate that reduced graphene oxide anchored nanocrystalline antimony particles (Sb/RGO) based sodium-ion batteries (SIBs) anode affords a stable capacity for 100 cycles with minimum capacity fade (~1.1%) by varying the RGO content. The optimum RGO content (~15 wt.%) is able to withstand the severe volumetric strain of SbNPs during sodium-ion alloying/de-alloying reactions and thereby prevents the detachment of Sb particles from the current collector. The improved electrochemical performance of optimal RGO anchored SbNPs manly stems from the lower electrochemical charge transfer resistance (Rct) and accommodation of volumetric strains of Sb during cycling by RGO matrix. The optimal Sb/RGO anode exhibits excellent capacity (average discharge and charge capacity of ~374.8 mAhg-1 and ~366.9 mAhg-1, respectively from 1st to 100th cycle) and Coulombic efficiency (~98.8% from 1st to 100th cycle) with excellent capacity retention of ~74.8%. Among the Sb/RGO composite anodes, the anode (Sb/RGO-15wt%) with appropriate RGO content achieves an impressive reversible capacity of ~347.1 mAhg-1 after 100 cycles at a constant current rate of 100 mAg-1 and the rate capability of ~331.9, ~320.4, ~312.3, ~307.8, ~291.5, ~280.3, ~258.1, ~235.5, and ~339.7 mAhg-1 at, 0.2 Ag-1, 0.3 Ag-1, 0.4 Ag-1, 0.5 Ag-1, 0.75 Ag-1, 1 Ag-1, 1.5 Ag-1, 2 Ag-1, and 0.1 Ag-1 current rate, respectively.

Figure 1
Solvate Ionic Liquid Electrolytes for Mg Batteries
Authors: Dokko Kaoru , Suzuki Soma , Terada Shoshi , Hashimoto Kei , Tsuzuki Seiji , Thomas Morgan L. , Mandai Toshihiko , Watanabe Masayoshi
Published: February 2020

We report here the structures and physicochemical properties of Mg[N(SO2CF3)2]2 (MgTFSA2)/glyme solvate ionic liquid electrolytes for Mg batteries. MgTFSA2 and certain glymes, such as triglyme (G3), tetraglyme (G4), and pentaglyme (G5), form equimolar complexes.1 The melting points of [Mg(G3)]TFSA2, [Mg(G4)]TFSA2, and [Mg(G5)]TFSA2 complexes are 70, 138, and 141 °C, respectively. X-ray crystallography revealed that each glyme wraparound a Mg2+ ion and forms a [Mg(glyme)]2+ complex cation in the crystalline solvate. To decrease the melting points of (MgTFSA2)/glyme complexes, asymmetric structure was introduced to the ligand (glyme). One of the terminal methyl groups of G3 molecule was substituted with other alkyl groups having various chain lengths. In this study, we used triethylene glycol ethyl methyl ether (G3Et) triethylene glycol butyl methyl ether (G3Bu) as ligands. As we expected, the melting point of [Mg(G3Et)]TFSA2 is 57.3 °C, which is lower than that of [Mg(G3)]TFSA2.2 The entropic term of melting increased with increasing asymmetric alkyl chain length, indicating that conformational flexibility successfully decreased the melting point. [Mg(G3Bu)]TFSA2 became a glass forming liquid and maintained liquid state at room temperature. Raman spectra for the [Mg(G3Bu)]TFSA2 indicated that the 1:1 complex structure of [Mg(G3Bu)]2+ is kept even in the liquid state. [Mg(G3Bu)]TFSA2 is thermally stable and does not decompose up to 251 °C. The oxidative stability of [Mg(G3Bu)]TFSA2 was analyzed by linear sweep voltammetry. [Mg(G3Bu)]TFSA2 possesses a higher oxidative stability compared with uncoordinated glymes. This is because the HOMO energy level of glyme is lowered by the complexation with Mg2+ ion.1,3 Mg metal deposition and dissolution are also possible in this electrolyte. Physicochemical properties of [Mg(glyme)]TFSA2 complexes will be compared with those of other glyme-based solvate ionic liquids such as [Li(glyme)]TFSA and [Na(glyme)]TFSA.

Acknowledgements

This study was supported in part by JSPS KAKENHI (Grant Nos. 18H03926) from the Japan Society for the Promotion of Science (JSPS), the MEXT program “Elements Strategy Initiative to Form Core Research Center” of the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan and the Advanced Low Carbon Technology Research and Development Program (ALCA) of the Japan Science and Technology Agency (JST).

References

S. Tsuzuki, T. Mandai, S. Suzuki, W. Shinoda, T. Nakamura, K. Ueno, S. Seki, Y. Umebaysashi, K. Dokko, M. Watanabe, Phys. Chem. Chem. Phys., 2017, 19, 18262-18272.

K. Hashimoto, S. Suzuki, Morgan L. Thomas, T. Mandai, S. Tsuzuki, K. Dokko, Phys. Chem. Chem. Phys.,
2018, 20, 7998-8007.

T. Mandai, K. Dokko, M. Watanabe, Chem. Rec.
2019, 19, 708-722.
Lithium Ion Conducting Block Copolymers: Conductivity and Battery Performance
Authors: He Yubin , Min Youn Ji , Liu Nian , Kohl Paul A
Published: February 2020

Polymeric solid electrolytes are an enabling technology for an all solid-state lithium battery using an intercalation or metal anode. In this study, random and block copolymers with polar functional groups were characterized for use in lithium batteries. The focus of this talk is on the lithium ion conductivity and structure-property relationship of the solid polymer electrolyte.

The block copolymer is synthesized by sequential raft polymerization of different monomers. The first block is poly(acrylate) or poly(styrene), which is imparts sufficient mechanical properties to the polymer. The second block is poly(carbonate) (PC) or polyethylene glycol (PEG) to solvate the lithium ions. Nano-phase separation occurs when the polymer is cast due to differences in polarity between the two blocks. Lithium salts and plasticizer are included in the polymer mixture. The interconnected polycarbonate phase provides ion conducting channels for lithium ion conduction. The mechanical properties of the solid polymer electrolyte are also improved by creating a crosslinking network.

Experimentally, a series of block co-polymers with different molecular weight and block ratio have been synthesized. The chemical structure of the block co-polymers was characterized by NMR and gel permeation chromatography. The nano-phase separation is confirmed by small angle scattering spectroscopy. Li ion conductivity was measured by electrochemical impedance spectroscopy (EIS). The battery performance was tested with Li metal anode and LiFePO4 cathode. The relationship between polymer structure, nano-phase separation and membrane performance will be discussed in this talk.
Conducting Polymers for Batteries
Authors: Chhin Danny , Padilla-Sampson Laura , Lepage David , Savignac Laurence , Nazemi Ali , Schougaard Steen Brian
Published: February 2020

Charge storage in organics has been a dream for many years. In part because organics offer advantages in terms of processing, sourcing of starting materials, and a high degree of tailorability. The first part of the talk, will cover recent advances in using conductive polymers to enhance performance of classical battery chemistries. This is followed by our recent work using catechols as the charge storing unit, specifically using blended and co-polymer techniques. A major part of the talk will be devoted to the challenges and methods of characterizing the charged and discharged state of these new charge storage systems.
Scalable Synthesis of Li2S-Based Composite Cathodes from Li2SO4
Authors: Johnson Billy , Glaser Rebecca , Ewers Kyle , Spivock Bryston , Sanghadasa Mohan , Yushin Gleb
Published: February 2020

Lithium-sulfur is commonly considered as one of the most promising chemistries for replacing traditional lithium-ion batteries in weight sensitive applications due to high theoretical capacity of sulfur (S) and lithium sulfide (Li2S) and high gravimetric energy density of such cells. Fully-lithiated (Li2S) cathodes are of greater interest than elemental sulfur cathodes because they can be used with lithium-free anodes during cell assemblage, are significantly more thermally stable, and offer greater mechanical stability as no further volumetric expansion occurs upon cycling. However, commercially available Li2S particles are not suitable for use in cells: they are too bulky in size (even after milling), must be handled only in inert atmospheres (making production of high-performance cathode materials, on a commercial scale, quite difficult) and suffer from rapid degradation in cells during cycling. The large particle size results in poor active material utilization and subsequently poor specific capacity. Another intrinsic difficulty that must be overcome to supplant traditional lithium-ion batteries is a poor cycle life due to the formation and dissolution of polysulfide intermediates that takes place upon a direct contact of active material with electrolyte during cycling. The dissolved polysulfides deposit on the surface of both electrodes resulting in a rapid impedance growth, loss in active material and ultimately battery failure. In this work, we report on a simple, safe and scalable production of chemically and electrochemically stable Li2S-carbon composite cathode materials, where nanosized Li2S particles are embedded into an ionically and electronically conductive carbon matrix and further protected from the undesirable interactions with electrolyte by a carbon shell to attain high capacity utilization and stable performance in cells. Low-cost Li2SO4 is used as an environmentally friendly precursor for Li2S. The effect of carbon source and structure and processing conditions on the electrochemical performance will be discussed.
Metal Phosphide-Embedded Phosphorus-Based Nanocomposite Anode Materials for Rechargeable Batteries
Authors: Kim Sang-Ok
Published: February 2020

The development of high-performance rechargeable batteries including advanced lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) has been accelerated due to the rapid growth of electric vehicles and stationary large-scale energy storage systems. As one of promising alloying-based anode candidates, elemental phosphorus has attracted much attention among researchers because of its significantly high theoretical specific capacity of 2595 mA h g-1 in both LIBs and SIBs, low-cost, and environmental benignity. However, there are shortcomings such as the large volume change during alloying/dealloying reactions and low conductivity (10-14 S cm-1) of phosphorus, which results in poor cycle performance and slow electrode kinetics. Most approaches aiming at the development of phosphorus-based anode materials have focused on overcoming these difficulties through the utilization of composite structure with nanoscale carbonaceous materials as conductive buffer matrices. While these composites have shown improved cycle and rate performance of phosphorus, they suffer from low initial charge/discharge efficiency and low energy density due to the high carbon content in the structure.

In this work, phosphorus-based nanocomposites containing both metal phosphide structure-reinforcing buffer and carbon network have been synthesized by a simple mechanical ball milling method. Morphological characterization shows that metal phosphide particles are well-mixed with phosphorus and further dispersed in carbon matrix. The resultant phosphorus-based nanocomposites exhibit a significantly improved electrochemical performance compared with amorphous red phosphorus, with a high initial Coulombic efficiency of over 80% in both LIB and SIB systems. Combined structural and electrochemical investigation demostrates that the performance improvement is mainly attributed to the presence of conductive phosphide inclusions that mitigates structural degradation and offers high conductivity.
Electrochemical Properties of Chemical Composition-Tuned SnPx/C Nanocomposite Anode in a Sodium-Ion Battery
Authors: Song Hayong , Lee Hwon-gi , Eom KwangSup
Published: February 2020

Tin phosphides (SnPx) has been considered as one of the most promising anode materials for sodium-ion batteries (SIBs) due to the high theoretical volumetric and gravimetric capacities. Nevertheless, SnPx has a low electrical conductivity and undergoes the severe pulverization resulted from a large volume change during sodiation/desodiation process, which leads to rapid decline in the performance. These problems can be solved by tuning nanostructure of the composite materials composed of SnPx and conductive carbon materials. On the other hand, SnPx has three different forms depending on phosphorus (P) content, Sn4P3, SnP, and SnP3, the higher the P content provide the higher theoretical capacity because the theoretical capacity of P is about three times higher than metallic tin. However, only a method using ball milling has been reported for the synthesis of SnPx having a high P content, and the nanostructure can’t be precisely controlled by this method [1]. Additionally, solvothermal method between metallic tin and red P allows to prepare thenanostructured SnPx/C composite, however, it gives only Sn4P3 phase which has the lowest P content [2].

In this work, to suggest the appropriate nanostructure and P content to obtain the high reversible capacity of SnPx as well as improved rate capability in SIBs, we synthesized hybrid nanocomposites composed of size-controlled SnPx (x = 3/4, 1, and 3) nanoparticles and low-dimensional carbon material by a facile direct reaction method between liquid phase tin and gas phase P. Through this method, we could control the Sn/P composition by regulating of cooling rate after reaction and P partial pressure in a reactor, which is confirmed by XRD analysis of Fig. 1(a). Using the three types of as-prepared SnPx/C composites with different P contents and nanostructures., we investigated their electrochemical properties for sodium ion battery anodes The obtained SnPx/C nanocomposite with x=3/4, 1, and 2 showed 500, 610, and 810 mAh g-1 of reversible capacities, respectively, as anode active materials of SIBs. Although SnPx with the higher the P content gave the enhanced reversible capacity, the poor rate capability and cycle durability were obtained presumably due to the increased internal resistance components and volume expansion ratio. For this reason, SnPx/C anode requires the empty space, where the volume expansion of sodiated SnPx can be accommodated without pulverization. Specifically, by preparing the Yolk-shell structured SnP/C (Y-SnP/C) composite (Fig. 1(b)), we achieved 3 times larger capacity retention at 3.2 A g-1 of current density as shown in Fig. 1(c).

References

[1] X. Fan, J. Mao, Y. Zhu, C. Luo, L. Suo, T. Gao, F. Han, S-C. Liou, and C. Wang, Adv. Energy Mater., 2015, 5, 1500174

[2] J. Liu, P. Kopold, C. Wu, P. A. van Aken, J. Maier, and Y. Yu, Energy Environ. Sci., 2015, 8, 3531-3538

Figure 1
A Highly Conductive Artificial Interface Layer Based on V
O-Rich Zirconia/Polymer Hybrid Nanoparticles for Stable Lithium Plating/Stripping
Authors: Li Sipei , Whitacre Jay , Matyjaszewski Krzysztof
Published: February 2020

The ability to implement a lithium metal anode is regarded as enabling technology for next-generation high-energy-density rechargeable batteries. However the unstable interface between the metallic lithium and electrolytes leads to formation of lithium dendrite that can result in both low Coulombic efficiencies and ultimately cell failure. In this work, we explore the promise of implementing a “purpose made” SEI layer directly onto the metallic lithium surface to counter deleterious effects. Specifically, polymer/inorganic composites containing hybrid nanoparticles were prepared by covalently grafting polyacrylontrile (PAN) from oxygen vacancy (Vo) rich yttria stabilized zirconia (YSZ) nanoparticles using atom transfer radical polymerization (ATRP). A thin layer of the YSZ-PAN hybrids was coated onto the surface of metallic lithium anode as an artificial SEI. It was found that the YSZ-PAN hybrids materials showed high ionic conductivity (> 10-4S/cm at r.t.), improved transference number (>0.5) and robust mechanical strength. Due to these unique properties, the YSZ-PAN hybrids SEI greatly improved the lithium stripping/plating process with up to 600 hundred hours of symmetric cycling at 1 mA/cm2 without voltage polarization.

Figure 1
Composite Anode of Lithium Metal Powder and Graphite for Improving Performance of Lithium Metal Anode
Authors: Go Nak Gyu , Lee Seung Taek , Yoon Woo Young
Published: February 2020

Over the last several decades, new battery technologies have been developed due to the need for consistently high energy density batteries. Lithium metal is the ideal cathode for next-generation lithium batteries, because it has a high specific capacity (3860 mAh g−1) and the lowest reduction potential (−3.040 V vs. standard hydrogen electrode, SHE). However, safety issues caused by Li dendritic growth during Li plating interfere with the use of lithium metal-based rechargeable batteries. Li dendrites can cause dead lithium to accumulate on the lithium metal surface, resulting in increased resistance at the interface or short-circuiting, which can lead to explosion. Several studies have been proposed to inhibit the growth of lithium dendrites, such as electrolyte additives, surface coating, separator modification, and lithium metal host. In this experiment, Li was isolated by physically mixing Li and graphite to form a composite electrode, thereby suppressing Li dendrite growth. Li metal powder is synthesized by the droplet emulsion technique and this shape is prohibited dendrite growth. These Li metal powder+graphite composite anode was experimented with constant current charge/discharge tests and constant voltage tests. And the structure, morphology, and electrochemical properties of the new type of battery’s electrode were investigated by the implementation of X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and energy dispersive spectroscopy (EDS). The result was analyzed by electrochemical impedance spectroscopy (EIS).