bluuebunny/crossref_metadata_2025 huggingface dataset:
“Water-in-Salt” Electrolyte Promises Reversible Anion Intercalation into Graphite for Energy Storage Applications
Authors: Zafar Zahid Ali , Abbas Ghulam , Silhavik Martin , Cervenka Jiri
Published: December 2020

Electrochemical energy storage systems (EESS) with high energy density, safety, low cost, and low carbon footprint have become indispensable in the modern era of ubiquitous electronics, electric vehicles, and grid storage. Current EESS lack of these characteristics due to the utilization of critical materials which are precious, flammable and difficult to recycle. Whereas, aqueous electrolytes offer higher safety and lower costs. Nevertheless, their biggest bottleneck is the narrow electrochemical window (1.23V) that is preventing from attaining higher energy and power densities in most of the aqueous EESS. For instance, aqueous rechargeable aluminum ion batteries promise high energy density due to multivalent redox chemistry of aluminum ion (Al3+) but they exhibit much lower energy density in real experiments due to the limited electrochemical windows of the aqueous electrolytes. The water-in-salt based electrolytes (WiSE) can potentially eliminate this barrier by offering a larger electrochemical window by reducing the overall electrochemical activity of water on the electrodes. Here, we demonstrate a new concept using aluminum perchlorate based WiSE that is showing a stable and wide electrochemical window of nearly 4 V against Ag/AgCl. The electrochemistry tests of the electrolyte are performed using carbon-based redox-active electrode materials. We employ the new electrochemical system in aqueous rechargeable aluminum ion batteries, revealing superior performance to standard aqueous electrolytes. Our findings provide new possibilities for widening the electrochemical window and enhancing the energy and power density in aqueous EESS.
Probing the Operating Voltage and Structural Transitions in Li-Mn-O Layered-Spinel Composite Nanoarchitectures during the Discharge Process.
Authors: Hlungwani Donald , Ledwaba Raesibe Sylvia , Ngoepe Phuti
Published: December 2020

Li-Mn-O layered-spinel (LS) composite is one of the utmost promising cathode materials for advancing lithium-ion batteries, which are lacking in comparison to technological advancements. The currently used cathode materials are one of the limiting factors in realising the envisaged affordable, durable, and safe rechargeable lithium-ion batteries. Their limitations include capacity fading transpiring during cycling, inherent low operational capacities, safety issues due to thermal instabilities, and high cost which inhibit their full utilisation in large scale systems. The LS composite demonstrates enhanced electrochemical properties owing to the synergism of the layered and spinel components. In particular, the 0.7Li2MnO3.0.3Li4Mn5O12 composite, which has demonstrated a higher specific capacity, >250 mAh/g. Recent studies have focused mainly on enhancing the specific capacity of LS composites. However, there is limited knowledge of the structural changes that take place during the discharge process and how they affect the working voltage of the LS composite cathode material. Li-Mn-O LS composites indicating different stages of the discharge process have been generated using the molecular dynamics simulated amorphisation and recrystallisation method, which utilises empirical interatomic potentials. Different structural features of the LS composites in all significant stages of the discharge process were visualised and captured. X-ray diffraction patterns (XRDs) and radial distribution functions were used to characterise the formed layered and spinel components of the LS blend nanoparticles. Moreover, their average voltages were also computed using the linear scaling density functional theory code.
Application of Thin Film As Polymer Gel Electrolyte for 3D Li-Ion Battery
Authors: Tolganbek Nurbol , Serik Nurassyl , Batrygali Nursaule , Naizakarayev Miras , Mentbayeva Almagul , Bakenov Zhumabay
Published: December 2020

Three-dimensional materials can improve the performance of energy storage systems by providing large active surface. Thus, the research was focused on designing a full 3D battery based on electrodeposited Ni3Sn4 (Ni-Sn) anode and polymer gel electrolyte/separator that was coated via layer-by-layer (LbL) technique. Advantages of the LbL approach was appliance of polymer material onto a rough surface of 3D structured electrode material, and thickness control of the coated gel polymer electrolyte. The structure of deposited electrode material was confirmed by XRD. The thickness estimation of coated layers, and cross-section view of 3D battery were depicted via SEM. Electrochemical activity of Ni-Sn alloy with LbL coated gel electrolyte demonstrated redox couples for lithiation and delithiation processes. LbL technique proved that polymer can be coated uniformly onto 3D structure electrode and function as the electrolyte and separator.

Acknowledgement

This research was supported by the research grants #091019CRP2114 “Three-dimensional all solid state rechargeable batteries” from Nazarbayev University.
The Role of Niobium Substitution in Lithium Vanadyl Phosphate for Lithium-Ion Batteries
Authors: Lee Krystal , Hidalgo Marc Francis , Zong Yanxu , Chernova Natasha , Zhou Guangwen , Liu Hao , Whittingham Stan
Published: December 2020

Li-ion intercalation compound enlisting multi-electron redox is a promising strategy to maximize the storage capacity of LIBs. Lithium vanadyl phosphate, LiVOPO4, is one such material that can intercalate up to two Li+ ions per vanadium ion through the change in vanadium valence from V5+ to V3+, which translates to a theoretical capacity of 305 mAh/g and an energy density above 900 Wh/kg. However, Li-ion intercalation in the high voltage region (V5+/V4+) is kinetically limited by the sluggish Li-ion diffusion, and thus impedes the use of LiVOPO4 in practical applications. The goal of this work is to explore experimentally if niobium substitution can enhance the electrochemical performance of LiVOPO4. Lab X-ray diffraction, electron microscopy-energy-dispersive X-ray analysis, and inductively coupled plasma atomic emission spectroscopy indicate niobium is substituted into the LiVOPO4 crystal structure. A qualitative difference in the charge-discharge voltage profile is observed between the pristine and the niobium-substituted samples, suggesting a more complex substitution mechanism than the direct V substitution with Nb. The effects of niobium substitution on the crystal structure and the electrochemical performance of LiVOPO4 will be discussed.
(Invited) Insight into Interfacial Processes between Lithium-Rich Layered Oxide Cathode and High-Voltage Electrolyte
Authors: Song Seung-Wan
Published: December 2020

Lithium-rich layered oxide, xLi2MnO3·(1-x)LiMO2 (M = Mn/Ni/Co), is a promising high-capacity cathode active material for high-energy density rechargeable lithium batteries. While the capacity of lithium-rich layered oxide cathode can increase by increasing the charge cut-off voltage toward 5 V, it t relies on the anodic stability of electrolyte and the interface stability of charged cathode. We have been developing and suggesting fluorinated carbonates as effective high-voltage additives and solvents of new designed electrolytes, which provide a significant improvement in the stability of cathode-electrolyte interface, solid electrolyte interphase (SEI) layer and cycling performance, and longer life span of various high-capacity cathodes, with respect to commercial electrolyte system. Herein, we present our recent progress on the exploration of the limit of anodic stability of fluorinated carbonate-assisted electrolyte toward 5 V level and the capacity of a Li-rich cathode based full-cell, and the enhancement of battery safety. The mechanistic studies utilizing systematic spectroscopic analyses on the correlation among interfacial processes, the SEI formation and stabilization, and performance improvement would be discussed in the meeting.

Acknowledgements

This research was supported by the Ministry of Trade, Industry and Energy (A0022-00725) and the National Research Foundation grant (2019R1A2C1084024) funded by the Ministry of Science and ICT of Korea.
(Invited) SEI or Solvation Structure: What Determines Electrode Stability in Rechargeable Batteries?
Authors: Li Qian , Cao Zhen , Cavallo Luigi , Sun Yang-Kook , Alshareef Husam N. , Ming Jun
Published: December 2020

Solid-electrolyte interphase (SEI) chemistry has garnered significant research interest in the past two decades because of its positive effect on boosting electrode performance in rechargeable batteries. Herein, we present a new viewpoint based on metal ion solvation structure and molecular-scale interfacial model on electrode surface, which could compliment exiting knowledge about the SEI effect. We show that the observed variation in de-solvation behavior of mobile ions also depends on their solvation structure, which is determined by multiple factors (e.g., cations, solvents, anions, and additives present in the electrolyte). The presented interfacial model can predict the experimentally-observed electrode performance (e.g., graphite, alloying, metal anode, and cathode) in different types of electrolytes. Our model can predict electrode performance through the proposed cation-solvent interactions and de-solvation behaviors, and can be used as basis to develop new types of electrolytes for mobile (ion) batteries.
Effect of Lithium Bis(oxalato) Borate Additive on Electrochemical Performances of 5V Class Cathodes at 60°C
Authors: Ha Seyoung , Han Jung-Gu , Song Young-Min , Choi Nam-Soon
Published: December 2020

Spinel LiNi0.5Mn1.5O4 material is one of the promising cathode materials for high energy density of lithium-ion batteries because of its high voltage, acceptable stability, and good cycling performance. However, these 5V class cathode has been noticed to be unwanted interfacial reaction with electrolyte at the high voltage. In this study, the positive impact of an electrolyte additive LiBOB on electrochemical performances of LiNi0.5Mn1.5O4 cathodes at 60°C will be discussed. In addition the oxidative decomposition of electrolytes at the cathode surface was investigated at various charged states by means of X-ray photoelectron spectroscopy(XPS) and scanning electron microscope(SEM).
Studies of Interfacial Reaction Behaviour of Nickel-Rich Cathode in Lithium-Ion Batteries
Authors: Tran Yen , An Kihun , Kwak Sehyun , Han Jisoo , Song Seung-Wan
Published: December 2020

Lithium-ion batteries (LIBs) are being dominant power sources for smart phones, electric vehicles and energy storage systems because of higher energy density, lighter weight, smaller volume design and longer cycle than other batteries. However, LIBs operated at high or low temperatures suffer from severe loss of power and energy due to degradation of structure and surface of cathode and anode, with an impedance rise. In addition, lithium plating occurs at a high rate cycling. Nickel-rich layered oxides of Li(Ni1
–

x

–

y
Co
x
Mn
y
)O2 (NCM, 1–x–y ≥ 0.5) has been regarded as a promising cathode active material because of high specific capacity and good thermal stability but its performance is limited by the interfacial stability with commercial electrolyte. In this presentation, we report our recent development and application of designed electrolyte that provides highly stable nickel-rich cathode-electrolyte interface under high-voltages. The correlation between improved performance and interface chemistry would be discussed in the meeting.

Acknowledgements: This research was supported by the National Research Foundation grant funded by the Ministry of Science and ICT (No. 2019R1A2C1084024) and Creative Human Resource Development Consortium for Fusion Technology of Functional Chemical/Bio Materials of BK Plus program by Ministry of Education of Korea.
Electrolyte Modification and Its Application for High Performance Li Metal Batteries
Authors: Zeng Ziqi , Jiang Zhipeng , Xie Jia
Published: December 2020

Lithium metal have received considerable attention as a promising anode material for next generation batteries because of its high theoretical capacity (3860 mAh g-1) and lowest electrochemical potential (-3.04 V vs. the standard hydrogen electrode), and lightweight. However, the irreversible consumption of electrolytes and the disordered dendrites growth could cause the low Coulombic efficiency and safety issues hindering the lithium anode from the commercialization. Various schemes, such as structured Li anodes, artificial SEI, and various electrolyte additives have been proposed to decouple the cycling lifespan of metallic Li anode with the dendritic growth. As one of the most critical components, the modification of the electrolyte will be one promising and complementary approach for preparing high performance Li metal battery. Inspired by these challenges, in this presentation the effects of novel highly concentrated electrolytes (HCEs) and diluted high concentration electrolytes (DHCEs) on the electrochemical performances of the Li metal anodes is provided. HCEs significantly improve the stability of lithium metal anodes, but applications are often impeded by their limitation of density, viscosity, and cost. To address such shortcomings without sacrificing their superiority in cycling performance, we introduce a new co-solvent to dilute the HCE. The performance of novel DHCE is further demonstrated in full cells under practical conditions, including ambient to low temperature (−20 °C), high areal capacity (7.6 mAh cm−2), high current density (3 mA cm−2), limited excess Li (20 μm Li), and lean electrolyte (3 g Ah−1).
Visualization of Ion Transport and Electrode/Electrolyte Interaction in Electrolytes for Lithium Metal Batteries
Authors: Yang Yuan , Cheng Qian , Min Wei
Published: December 2020

Visualization of ion transport in electrolyte provides fundamental understandings of electrolyte dynamics and electrolyte-electrode interaction, shedding light on material designs to enhance device performance, such as batteries and fuel cells. However, this task is challenging for existing techniques, since it is difficult to capture the low ionic concentration (<1 M) and the fast dynamics (1-10 s) of the electrolyte. Here we show that an emerging Stimulated Raman Scattering (SRS) microscopy offers the required spatial (sub-micrometer optical resolution), temporal (faster than 1 s per frame) and chemical (around mM) sensitivities to address this challenge.

The SRS microscopy has been used to study ion depletion and lithium dendrite growth in both liquid and polymer electrolyte, and distinct behaviors are observed. In liquid electrolyte, we observe a three-stage lithium deposition process, each corresponding to no-depletion, partial-depletion and full-depletion regime of Li+, respectively. A positive feedback mechanism between the inhomogeneous growth of lithium and the local ionic concentration or flux. In polymer electrolyte, we clearly see phase separation due to ion depletion and observe the accompanying transport of plasticizer inside, which was not observed in the past. The new phase has significantly higher modulus than the bulk electrolyte. These new understanding also leads to new strategies to suppress lithium dendrites. This study shows that SRS microscopy is a powerful technique for imaging ion transport and will open various applications in materials and energy fields.

References:

Qian Cheng et al., Operando and three-dimensional visualization of anion depletion and lithium growth by stimulated Raman scattering microscopy, Nature Communications 9, Article number: 2942 (2018) .
(Invited) Lithium-Ion Transfer Kinetics through Solid Electrolyte Interphase on Graphite Electrodes
Authors: Abe Takeshi
Published: December 2020

For the development of lithium-ion batteries (LIBs) for EV, the internal resistances of LIBs should be required for rapid charge. We have focused on the elucidation of the active sites for lithium-ion intercalation/deintercalation reaction on the graphite negative electrodes. In this study, the influence of the SEI on active sites for lithium-ion intercalation/deintercalation at highly oriented pyrolytic graphite (HOPG) and graphite composite electrode was investigated. We clarified the relation between the standard rate constant (k
0) of [Ru(NH3)6]3+/2+ that is a parameter for edge site of graphite and the interfacial lithium-ion transfer resistance (R
ct) in various electrolyte solutions. In plots of k
0 vs. 1/R
ct, slopes of straight lines varied with electrolyte solutions. This means that the SEI partly blocked the active site, since the activation energies were not dependent on the SEIs. As a result , we could conclude that the number of the active sites for lithium-ion intercalation/deintercalation strongly depend on the kind of SEIs.
Control of Electrolyte Reactivity: A New Design of Electrolyte Additives for High Voltage Lithium Ion Batteries
Authors: Liao Chen , Yang Jianzhong , Shkrob Ilya A , Liu Kewei , Dietz Rago Nancy L. , Connell Justin G. , Zhang Zhengcheng
Published: December 2020

To reach a higher energy density, lithium ion batteries have been pushed to cycle at a higher voltage. The development of new high voltage electrolytes and additives are essential as the fading mechanism at high voltages is tied up with exacerbating oxidation, cathode electrolyte interface formation, as well as the blockage of accessible active Li+. The additive development strategy has mostly followed the trial and error principle, and a paradigm shift is hard.

Here we report a development strategy which tames the spontaneity of electrolyte reactivity and opens an avenue to new additives that would be impossible to achieve otherwise. The talk will cover the recent development of a series of in-situ additives that utilize the reactivity of bistrimethylsilyl carboxylates with two -OSiMe3 groups to react with LiPF6 and form highly moisture sensitive lithium carboxylato phosphate additive (Figure 1).1,2 These additives targets at alleviating cathode impedance rise and show exceptional performance with NMC 532//Gr cell at 4.4 V.

Figure 1. Structure of in-situ additives and the exchange reaction between -O-TMS and LiPF6.

Recently we were also able to use a rational design to expand the family of in-situ additives to include functionality of - N-SiMe3 (TMSML, see Figure 1).4 High nickel cathodes show better performance with the -N-SiMe3 containing additive as they prevent the hydrolysis of LiPF6 caused by traces of water in a carbonate electrolyte, both ex and in situ. It also inhibits oxidative decomposition of electrolytes on the energized cathode through deactivation of the Transition Metal-Oxide (-TM-O.) radical center. We trace these beneficial functions to the ease of nucleophilic substitution and the formation of TM-O.N< that reduce electrolyte oxidation.

Overall, a new design of additives has been implemented with invention of two classes of new additives that improve the performance of high voltage lithium ion batteries.

References

I. Shkrob, B. Han, R. Sahore, A. P. Tornheim, L. Zhang, D. P. Abraham, F. Dogan, Z. Zhang, C. Liao,* Chemistry of Materials 2019, 31, 2459-2468.

Yang, I. Shkrob, Q. Liu, N. L. Dietz Rago, Y. Liu, K. Liu, Z. Zhang, C. Liao,* Journal of Power Sources 2019, 438, 227039.

Yang, I. Shkrob, K. Liu, J. Connell, N. L. Dietz Rago, Z. Zhang a and C. Liao*, J. Electrochemical Society, 167 (7), 070533

Figure 1
High-Voltage Performance Enhancement of Nickel-Rich Cathode through Improved Binding Ability of Designed Binder
Authors: Kwak Sehyun , Han Jisoo , Jung Hyun Min , Song Seung-Wan
Published: December 2020

As mobile electronics and electric vehicles become essential in our lives, the specific energy density of a lithium-ion battery is one of the criteria that determines the quality of a battery and customers’ use range. Cathode is the one that primarily determines the capacity and energy density of the battery, and consists of active material, binder and carbon black. Nickel-rich layered oxides such as LiNi0.8Co0.1Mn0.1O2 (NCM811) are promising high-capacity cathode active materials, and its reversible capacity increases more by charging to higher cut-off voltages than the conventional 4.2 V. We observed that NCM811 cathode fabricated with commercial polyvinylidene fluoride binder has an unstable interface to electrolyte under high cut-off charge voltages and undergoes drastic structural changes during cycling in particular at elevated temperature, leading to capacity fade and reduced lifespan of the battery. In order to acquire a high reversible capacity and enhanced cycling performance with NCM811 cathode by mitigating the problems, we have designed an unique and functional high-voltage binder and make the combination with NCM811. In the meeting, we are going to report improved thermal stability and cycling performance of the designed binder-assisted cathode.

Acknowledgement

This research was supported by the Ministry of SMEs and Startups (S2788978) of Korea, National Research Foundation grant funded by the Korean Ministry of Science and ICT (No. 2019R1A2C1084024) and Creative Human Resource Development Consortium for Fusion Technology of Functional Chemical/Bio Materials of BK Plus program by Ministry of Education of Korea.
Electrochemical Evaluation of the Application of Hydrogel Electrolytes to Rechargeable Zn|MnO2 Alkaline Batteries
Authors: Cho Jungsang , Huang Jinchao , Yadav Gautam Ganapati , Nyce Michael , Weiner Meir , Upreti Aditya , Messinger Robert J. , Banerjee Sanjoy
Published: December 2020

Zinc-manganese dioxide (Zn|MnO2) alkaline batteries have been widely studied as the active materials exhibit high theoretical capacities (820 mAh/g for Zn and 620 mAh/g for MnO2), low cost, and are inherent safety. Furthermore, the active materials are electrochemically active in aqueous alkaline electrolytes, such as potassium hydroxide (KOH), which is beneficial from a cost and safety perspective. It is widely known that one of the issues with this system is active MnO2 poisoning by zincate anions during the 2nd electron reaction of MnO2. As a result, an electrochemically inert material, ZnMn2O4 (hetaerolite), is formed, which reduces the capacity and cycle life of Zn|MnO2 batteries. Another issue is associated with high depth-of-discharge (DOD) of each material. For example, at high DOD, Zn will undergo shape change, dendritic growth and passivation, while MnO2 will form inactive phases like Mn3O4. Therefore, the 1st electron reaction range of MnO2 is normally accessed in rechargeable Zn|MnO2 batteries with low DOD.

We have observed that the use of alkaline-based hydrogel electrolytes can significantly increase the cycle life of Zn|MnO2 batteries. Large-scale Zn|MnO2 cells were tested with either hydrogel or conventional alkaline electrolytes, whose nameplate capacities were 95 Ah based on the 1st electron capacity of MnO2. The hydrogel electrolytes were formed by mixing KOH solution, acrylic acid, and potassium persulfate solution as an initiator. Galvanostatic tests were carried out at cycling rates of C/20 (4.75 A) with 20% DOD of the capacity (19 Ah). The single full discharge performance to 0 V with hydrogels was compared to that with KOH aqueous electrolytes. The cell with the KOH electrolyte showed two sigmoidal curves, which means that two steps of electrochemical reactions were undergone, achieving 131 Ah. After recharging it, the single full discharge was conducted again, but nevertheless it attained less than 4 Ah to 1 V onwards. On the contrary, the cell with the hydrogel presented one sigmoidal curve with 40 Ah to 0 V, and it was continuously able to extract discharge capacities ≥28 Ah to 1 V during 40 cycles. Thus, the hydrogel electrolytes significantly enhanced the electrochemical performance of Zn|MnO2 cells, compared to conventional KOH electrolytes, the reasons for which will be discussed. The results suggest that hydrogels could help preserve active materials without the aforementioned issues and make rechargeable Zn|MnO2 batteries achieve better performance while accessing the 1st electron reaction of MnO2.
(A04 Best Poster Award Winner) Improved Low-Temperature Performance of Lithium-Ion Battery with so2-Based Inorganic Electrolyte
Authors: Choi Seong Hoon , Lee Jiwhan , Youn Donghan , Ma Donghyeok , Kim Hansu
Published: December 2020

Lithium ion batteries (LIBs) are the most promising candidates for power source of energy storage systems, electronic devices, and electric vehicles, but still have some issues to be solved. Poor electrochemical performance of LIBs with the organic electrolyte at low temperature is one of the main concerns for applications under extreme condition. In this presentation, we demonstrate LIBs with mixture inorganic liquid electrolyte system of LiAlCl4-3SO2 and NaAlCl4-2SO2, of which the freezing point are under -10 ºC. It was found that the capacity of graphite electrode obtained in the inorganic liquid electrolyte was five times higher than that of organic liquid electrolyte at -20 ºC. It could be ascribed to lower interfacial impedance, higher molar density of Li ion and higher ionic conductivity of mixed SO2-based inorganic liquid electrolytes than organic electrolytes. Detailed mechanism of mixed inorganic electrolytes system will be discussed in the presentation.
The Sodium-Ion Battery: Effect of Electrolyte Additives on the SEI Layer of Hard Carbon Anodes
Authors: Dimogiannis Konstantinos , Bhaskar Akkisetty , Johnson Lee R
Published: December 2020

Since their discovery, lithium-ion batteries (LIBs) have dominated the energy storage and power market due to their attractive attributes. However, LIBs cannot cope with the ever-growing energy demand and new alternatives must be explored. The low cost, and abundance of sodium, as well as its similar chemical properties to lithium, make the sodium-ion battery (SIB) a promising alternative for the future.1-5

SIBs often suffer from a short cycle lifespan, which is mainly attributed to the formation of an unstable solid electrolyte interphase (SEI) layer on the hard carbon anode surface. During the first cycle, the electrolyte solution is reduced, and its decomposition products form a passivation film (SEI) on the anode. Ideally, the SEI should protect the electrolyte from further decomposition during subsequent cycling, while being permeable to sodium ions. To reach this ideal situation, the employment of film-forming electrolyte additives in small amounts is necessary.6-11

In this study, in-operando electrochemical quartz crystal microbalance is used to monitor how additives affect the mass variation during the sodium intercalation/de-intercalation process. Mass spectrometry is further employed to identify and quantify the generated gaseous species during the initial SEI formation. After cycling, scanning electron microscopy and X-ray photoelectron spectroscopy are used to explore the additives effect on the SEI thickness and composition. A range of additives are considered including 1,3-propane sultone, succinonitrile and sodium-difluoro(oxalato)borate. The results of this study will be presented, along with suggestions for future research.

Reference
s
:

[1] P. K. Nayak, L. Yang, W. Brehm, P. Adelhelm, Angew. Chem. Int. Ed. 57 (2018) 102–120.

[2] S. Roberts, E. Kendrick, Nanotechnol. Sci. Appl.11 (2018) 23-33.

[3] H. Li, X. Zhang, Z. Zhao, Z. Hu, X. Liu, G. Yu, Energy Storage Mater. 26 (2020) 83–104.

[4] J. Deng, W. B. Luo, S. L. Chou, H. K. Liu, S. X. Dou, Adv. Energy Mater. 8 (2018) 1–17.

[5] L. Li, Y. Zheng, S. Zhang, J. Yang, Z. Shao, Z. Guo, Energy Environ. Sci., 11 (2018) 2310–2340.

[6] G. Eshetu, M. Martinez-Ibañez, E. Sánchez-Diez, I. Gracia, L. Chunmei, L. M. Rodriguez-Martinez, T. Rojo, H. Zhang, M. Armand, Chem. Asian J. 13 (2018) 2770-2780.

[7] M. Dahbi, T. Nakano, N. Yabuuchi, S. Fujimura, K. Chihara, K. Kubota, J.Y. Son, Y.T. Cui, H. Oji, S. Komaba, ChemElectroChem, 3 (2016) 1856–1867.

[8] G. Yan, K. Reeves, D. Foix, Z. Li, C. Cometto, S. Mariyappan, M. Salanne, J.M. Tarascon, Adv. Energy Mater. 4 (2019) 36244–36251.

[9] S. Komaba, W. Murata, T. Ishikawa, N. Yabuuchi, T. Ozeki, T. Nakayama, O. Atsushi, G. Kazuma, K. Fujiwara, Adv. Funct. Mater. 21 (2011) 3859-3867.

[10] A. Bouibes, N. Takenaka, T. Fujie, K. Kubota, S. Komaba, M. Nagaoka, Appl. Mater. Interfaces. 10 (2018) 28525-28532.

[11] M.A. Muñoz-Márquez, D. Saurel, J.L. Gómez-Cámer, M. Casas-Cabanas, E. Castillo-Martínez, T. Rojo, Adv. Energy Mater. 7 (2017) 1-31.
Correlating Transient Mechanical and Electrochemical Behaviors in Lithium Ion Batteries
Authors: Hodson Thomas , Patil Shripad , Steingart Daniel A.
Published: December 2020

Lithium-ion batteries (LiBs) represent a dominant technology in the current energy storage market. However, many aspects of these batteries are still poorly understood, and proper engineering of these aspects will lead to increased cycle life and performance parameters. In particular, the electrode - electrolyte interface is still an actively researched topic and is notoriously difficult to study. A new ultrasound acoustic characterization technique is introduced to probe the electrode/electrolyte interface in operando using signal amplitude analysis. This technique gives insight into lithium ion concentration accumulation and depletion at the electrode/electrolyte interface, and these findings are consistent with Dualfoil model simulations.

Figure 1
Prevention of Dendrites on Graphite By K+ Cation Addition to Electrolyte
Authors: Moharana Sanghamitra , Busà Chiara , Walker Marc , West Geoff , Loveridge Melanie J
Published: December 2020

With the ever-increasing demand for energy, one of the biggest challenges with Lithium ion batteries (LIB) is to enable the fast charging capability for automotive electrification. However, graphite, the most common anode material for LIB cannot fully accommodate fast charging and provokes safety issues such as lithium plating and subsequent dendrite growth. This could lead to an internal short circuit, which can result in a fire in the battery. In this work, a systematic study has been performed with various concentrations of KPF6 salt addition to electrolyte in order to understand the effect of salt additives on dendritic growth in graphite anodes. K ions easily deposit on defect sites present on graphite particles, confirmed by secondary electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy detector (EDX). This prevents the dendrite formation by restricting the incoming Li ions even at 2C-rate (corresponding to 5.52mA) cycling, which was observed by SEM imaging. After close inspection, it concluded that, the KPF6 modified electrolyte is very much beneficial in inhibiting dendritic morphology without forming SEI products (confirmed by X-ray photoelectron spectroscopy; XPS). Moreover, there were no observable adverse effects on the electrochemical properties, such as capacity, ionic conductivity and resistance of the cell.
Investigating Abuse Tolerance and Improved Cycle Life in Si Anode Systems with Novel Electrolyte Design
Authors: Torres Gabriel , Brown Kevin , Raghunathan Aditya , Vaidya Rutvik , Moganty Surya
Published: December 2020

Si has emerged as the most promising successor to graphite as an anode material in Lithium-ion batteries. Known to have nearly ten times the capacity of graphite, Si is increasingly being used to partially replace traditional graphite to raise the overall energy density of a cell. High nickel cathode chemistries such as NMC811 are also of particular interest due to its high specific capacity and low cobalt content, which drives down cost. Pairing these active materials is an obvious design choice, however it results in combining their respective drawbacks. Relative to lower nickel NMCs, NMC811 has been shown to be more reactive with carbonate electrolyte components and is known to be more violently reactive upon thermal decomposition. Si based materials swell dramatically upon lithiation, causing the SEI layer to break and reform with repeated cycling, consuming the electrolyte in the process. In combination, high energy density also implies increased safety concerns. To overcome these problems new electrolyte additives are needed.

We report a new family of electrolyte additives designed to improve the robustness of the SEI and overall stability of the electrolyte system, which carries significance in improving cycle life and abuse tolerance in higher energy density cells. This is a tunable, drop-in solution to addressing the need for improving battery performance as well as safety. We demonstrate the effect of these additives on the SEI via analytical characterizations (SEM, XPS) and how it relates to improved long-term cycle life. The effect of additives on thermal decomposition at the material level is investigated via DSC and on the cell level via ARC, presenting a relationship between electrolyte design and inhibited electrode-electrolyte decomposition reactions. Novel electrolyte additives are thus shown to be a promising approach to resolving future high energy demand without compromising safety.
A Numerical Framework for Concentrated-Solution Theory
Authors: Van-Brunt Alexander John , Farrell Patrick E. , Monroe Charles W.
Published: December 2020

Effective and stable electrolytes will be crucial to the implementation of next-generation battery chemistries. In particular, the engineering of novel electrolytes that suppress dendrites and facilitate stable SEI formation, whilst maintaining high conductivity and other desirable transport properties, will be necessary to enable lithium-metal anodes. Beyond this, electrolyte models that account for multiple dissolved components would be useful to analyze metal-oxygen batteries and lithium-sulfur batteries, and could shed light on the numerous transport processes potentially associated with the known side reactions that degrade today's lithium-ion cells.

The Onsager--Stefan--Maxwell (OSM) equations from irreversible thermodynamics, which underpin concentrated solution theory, provide a natural framework for multicomponent-electrolyte multiphysics. OSM flux laws are force-explicit, however, which has led to difficulties in numerical implementation, and in turn posed a barrier for electrolyte designers to apply the transport equations in their most natural form. Leaving the implementation issues aside, the OSM formalism can be useful because it more readily includes additional physics such as elasticity and pressure, which could be important for developing accurate models of intercalation materials and solid electrolytes.

This presentation will focus on numerical methods applicable to complex geometries. We will develop a general methodology to compute solutions of OSM transport problems, with a particular focus on how robust, rapidly converging results can be achieved when simulating materials that span multiple spatial dimensions. This methodology can be applied in both ideal and non-ideal settings, and will be illustrated with a variety of three-dimensional simulations. Particular emphasis is placed on devising a numerical algorithm which preserves and exploits the thermodynamic structure of the problem. The role of physical effects such as pressure and momentum, which tend to be neglected in most continuum simulations, will be highlighted. Insight into electrolyte design from these simulations will be discussed, and comparisons will be made to experimental data.
Bioinspired Nanoporous Ion Conducting Membranes for Next Generation Batteries
Authors: Emre Ahmet , Fan Jinchen , Gerber Alycia , Cecen Volkan , Kotov Nicholas
Published: December 2020

Bioinspired ion transport membranes have been widely investigated for energy storage applications. High theoretical specific energy density (2600Wh/kg) and high specific capacity (1675mA/g) along with natural abundance and low toxicity of sulfur have been attracting significant attention for development of an alternative battery system to replace traditional lithium ion batteries which suffer from safety and capacity/energy density limitations in various applications. However, challenges such as polysulfide dissolution and shuttling prevent mass commercialization of metal sulfur batteries. Inspired from biological ion transport mechanisms, we show a practical yet comprehensive approach for development of high-performance metal sulfur batteries. Aramid nanofiber (ANF) based composite ion transport membranes not only prevent dendrite formation but also confine polysulfides on the cathode side. ANF composite battery separators provide diverse and opposing properties including high mechanical properties, high ionic conductivity and high thermal/chemical stability. Highly selective ion sieving properties of these biomimetic separators provide safe and high-performance batteries. Fabrication of such biocompatible, affordable, flexible and high energy density battery is quite crucial in powering next-generation electronics including but not limited to portable, wearable and implantable biomedical devices.
New Solid-State Electrolytes Based on Organic Ionic Plastic Crystals
Authors: Pringle Jenny , Yunis Ruhamah , Al-Masri Danah , Howlett Patrick C , Forsyth Maria , Hollenkamp Anthony F.
Published: December 2020

The development of new solid-state electrolytes for energy storage devices is important for increasing their stability, reliability and safety. Organic ionic plastic crystals (OIPCs) are a relatively new class of material that show increasing promise as solid state electrolytes for devices such as lithium or sodium batteries.[1]

OIPCs are crystalline phases found in many of the same organic salt families as ionic liquids but these materials have elevated melting points and exhibit various forms of disorder, which is the origin of their plastic mechanical properties. One of the keys to the development of OIPCs as solid state electrolytes is expanding the range of cations and anions available, and understanding the structure and dynamics of the resultant material.

For application in a device, OIPCs are combined with salts of the target ion (e.g. Li+ or Na+), after which detailed analysis of the electrochemical and device parameters is performed. OIPC-based electrolytes can also be combined with polymer nanofibers to further improve their mechanical and transport properties.

This presentation will provide an overview of the new OIPC families that we have recently designed and synthesized, and progress of these materials towards their use in practical solid-state lithium and sodium based batteries. We have also investigated the use of nanoscale polymer composites and the combination of OIPCs with very high concentrations of lithium or sodium salts,2 and the recent work on developing these composite materials will be discussed.

References:

[1] H. Zhu, D. R. MacFarlane, J. M. Pringle, M. Forsyth Trends in Chemistry, 2019, 1 (1), 126

[2] D. Al-Masri, R. Yunis, H. Zhu, L. Jin, P. Bruce, A. F. Hollenkamp, J. M. Pringle Journal of Materials Chemistry A, 2019, 7, 25389-25398
Designing Solid Electrolyte Interface for Stabilized Silicon Anode for Lithium-Ion Battery
Authors: Jiang Sisi , Zhang Zhengcheng
Published: December 2020

The exploration for the next generation of anode materials in the lithium-ion batteries is a vital subject in energy storage field. Silicon (Si) stands out among all the candidate materials due to its high theoretical specific capacity (4200 mAh/g for Li4.4Si), high safety and low cost. However, one of the biggest issues causing rapid capacity fade of Si anode is the continuous breakage and reformation of SEI due to unstable electrode/electrolyte interphase. One effective way to address it is to use electrolyte additives as represented by vinylene carbonate (VC) and fluoroethylene carbonate (FEC). It is believed that the decomposition of FEC generates electrochemical stable LiF and elastomeric polymerizable vinylene carbonate radical. These decomposition products form a passive layer on Si surface, leading to improved electrochemical performance. However, it is hard to control the composition and structure of the SEI.

We take a different approach attempting to solve the above issue. Organic functional groups are introduced on the surface of Si nanoparticles (SiNPs) via Pt-catalyzed hydrosilylation reaction. The surface group helps form more robust SEI thus boosts the electrochemical performance of silicon anode evidenced in both half- and full-cells. This method provides an efficient approach confronting the issues associated with SEI.

Figure 1
Characterization of Solid Electrolyte Interphase on Some Electrodes in the Bis(fluorosulfonyl)Amide Anion-Based Ionic Liquids with Different Li Salt Concentrations
Authors: Furuya Ryota , Hara Tomitaro , Fukunaga Takao , Kawakami Kiyomoto , Serizawa Nobuyuki , Katayama Yasushi
Published: December 2020

Aprotic ionic liquids are investigated as the next generation electrolytes for lithium ion battery (LIB) because non-flammability of ionic liquids is expected to improve the safety of the LIB. Bis(fluorosulfonyl)amide (FSA) anion-based ionic liquids have been attracting attention because of the formation of stable solid-electrolyte interphase (SEI) on the electrode surface during charge-discharge reactions. The SEI is known to form as a result of reductive decomposition of electrolytes and considered as a lithium ion conductor, though its nature like composition has not been clarified yet especially in ionic liquid electrolytes. In the present study, the SEIs on some different electrodes in 1-methyl-1-propylpyrrolidinium bis(fluorosulfonyl)amide (MPPFSA) containing LiFSA at different concentrations were characterized by electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS).

The formation and growth of the SEI were confirmed by the EIS spectra of a Cu electrode kept at 0 V vs. Li|Li(I) and Li deposited on a Cu electrode in MPPFSA containing different concentrations of LiFSA with the elapse of time.

The SEIs prepared on the Cu electrode and the deposited Li in the electrolytes for 1 week were characterized by XPS washing with monoglyme (G1) without exposure to air. The XPS peaks corresponding to C, N, O, F, S atoms were observed on the Cu electrode, suggesting the ionic liquids are adsorbed on the electrode surfaces even after washing by G1. Such decomposition products of the electrolytes as LiF and LiOH were detected on the Cu electrode and the deposited Li. In case of the deposited Li, the peak assignable to alkyl lithium (R-Li) in the C1s spectra was observed probably due to the reaction of Li with the organic cation of the ionic liquids. The ratio of the peak intensity for LiF to that for SO2-F on the Cu electrode and the deposited Li increased with an increase in the LiFSA concentration in the electrolyte. On the other hand, the relative intensity for R-Li on the deposited Li decreased with an increase in the LiFSA concentration, suggesting an increase in the LiFSA concentration suppressed the decomposition of MPP+ and promoted the decomposition of FSA-.
Improvement on Electrochemical Performance and Safety Using Mixtures of Ionic Liquid and Conventional Organic Electrolyte for Sodium-Ion Batteries
Authors: Hwang Jinkwang , Huan Yang , Matsumoto Kazuhiko , Hagiwara Rika
Published: December 2020

The success of commercializing sodium-ion batteries is inhibited by the implementation of suitable electrolytes that have economic feasibility and stable electrochemical performance. Organic electrolytes such as Na[ClO4]- or Na[PF6]-including organic solvents, EC, PC, DMC, and DEC, are most widely used to investigate the performance of sodium-ion batteries. These electrolytes are widely accepted because of the analogous studies in LIBs, but their flammability can cause reliability issues. Moreover, the SEI layer composed of sodium cations is known to be inhomogeneous and fragile, giving a higher solubility than that based on lithium cations.(1) In this regard, ionic liquid electrolytes are a drawing huge attention to constructing safe electrochemical devices owing to their unique properties such as low volatility and low flammability. Furthermore, recent studies report ionic liquids show similar electrochemical performance at room temperature to organic electrolytes and better interfacial properties.(2-4) Despite this bright improvement, the cost of ionic liquids drags down the advantage of economical sodium-ion batteries.

In this study, ionic liquid and organic liquid electrolytes are mixed to adjust the balance of cost, performance, and safety. The [C3C1pyrr][FSA] (C3C1pyrr+ = N-methyl-N-propylpyrrolidinium) ionic liquid and PC organic solvent are used as mother electrolytes with Na[FSA] (FSA = bis(fluorosulfonyl)amide) and Na[ClO4] salts. The physical and electrochemical properties of the various mixing ratio of those mixture electrolytes are investigated for sodium-ion batteries. These mixture electrolytes improve not only flammability but also show better rate and cycling performance. The detailed electrochemical properties are evaluated by comparing reference electrolytes to clarify the dual salts effect and dual solvents (ionic liquids and organic solvent) effect. This performance will be discussed based on half cell tests using a Na2FeP2O7 positive electrode and full cell tests using a hard carbon negative electrode and a NaCrO2 positive electrode.

References

1. G. Yan, D. Alves-Dalla-Corte, W. Yin, N. Madern, G. Gachot, J.-M. Tarascon, J. Electrochem. Soc.,
165, A1222 (2018).

2. K. Matsumoto, J. Hwang, S. Kaushik, C.-Y. Chen, R. Hagiwara, Energy Environ. Sci.,
12, 3247. (2019).

3. J. Hwang, K. Matsumoto, Y. Orikasa, M. Katayama, Y. Inada, T. Nohira, R. Hagiwara, J. Power Sources, 377, 80 (2018).

4. J. Hwang, K. Takeuchi, K. .Matsumoto, R. Hagiwara, J. Mater. Chem. A,
7, 27057 (2019)
Data Driven Approach for Predicting Thermal Runaway in Li Ion Battery
Authors: Ragone Marco , Yurkiv Vitaliy , Ramasubramanian Ajaykrishna , Anahideh Hadis , Kashir Babak , Shahbazian-Yassar Reza , Mashayek Farzad
Published: December 2020

Safety problems of high energy density and high-power Li-ion batteries (LIBs) associated with thermal runaway (TRA) have become a serious problem resulting in massive recalls by manufacturers, and at times even endangering the lives of the consumers. In general, the TRA consists of a battery’s rapid self-heating sourced from exothermic (electro-)chemical reactions and/or mechanical abuse. It is impossible to directly monitor the occurring events during the TRA in practical operating conditions (e.g., in cell phones or electric vehicles). However, the change in electrical parameters (pattern) during the TRA-like events could potentially indicate the existence of a failure, thus allowing to foresee the LIBs malfunction.

In this contribution, we employ multi-physics modeling and machine learning (ML) to address this important TRA problem in LIBs. Specifically, we use ML techniques to learn and predict the likelihood of the TRA, using the data acquired from the multi-physics modeling of LIBs. The multi-physics modeling approach is comprised of a coupled thermal, electrochemical (P2D model) and degradation sub-models. In this work, a degradation phenomenon leading to the TRA is the solid electrolyte interface (SEI) formation/decomposition in the negative electrode. Subsequently, due to the time-varying characteristic of the variables affecting TRA (i.e, voltage, C-rate, state-of-charge, temperature, etc.), we propose three ML techniques, namely, Support Vector Machine, Deep Neural Network, and Recurrent Neural Network to be customized and applied for determining the TRA likelihood. For deep learning methods, we propose a new activation function, TK-MARS, based upon a partitioning based multivariate adaptive regression spline (MARS). Finally, to mitigate the uncertainty of the prediction results under different degradation conditions, we built an ensemble framework (i.e., a committee of single prediction models) incorporating the trained individual models, in order to maximize the robustness and generalization power of the prediction for a new unseen observation without prior knowledge on the degradation. Thus, the developed combined multi-physics and ML modeling approach establish a basis for accelerated or ‘on-the-fly’ prediction of the TRA as well as a framework for extending machine learning methodologies to broad applications in electrochemistry.