bluuebunny/crossref_metadata_2025 huggingface dataset:
(Plenary) NMR and PDF Studies of Local Structure and Dynamics: Applications to Lithium and Sodium Ion Batteries
Authors: Stratford Josh , Allan Phoebe , Griffith Kent J. , Marbella Lauren , Grey Clare P.
Published: February 2020

This talk will focus on method developments to understand structure and dynamics in Li, Na and Mg batteries using a series of local structural probes. Recent studies to improve our understanding of hard carbons for Na-ion batteries will be discussed using both NMR and pair distribution function (PDF) analysis. Here we use both methods to correlate structure with the capacity observed in both the sloping and flat, low voltage component of the electrochemical curve. NMR studies to study dynamics in lithium-ion cathode and anode materials will be discussed. For example, a series of high rate Nb-oxide electrodes and the structures that allow high Li transport and extremely high rates even when micrometer-sized will be described. These structures adopt crystallographic shear and bronze-like structures, and retain open diffusional channels for Li over a wide range of lithium compositions. In part, this is due to structural motifs present in, for example, the shear structures that prevent rotation of the perovskite corner edge sharing octahedra that clamp the Li in place in ReO3-type structures. Their lithium-ion diffusion coefficients (D
Li) were measured with pulsed field gradient NMR spectroscopy and have room temperature values that are several orders-of-magnitude faster than typical electrode materials.
(Keynote) Ionic Liquids, Mixed Electrolytes and Their Iongels for Stable Na Metal Devices
Authors: Forsyth Maria , Howlett Patrick C , Armand Michel , Rojo Teófilo , MacFarlane Douglas R. , Mecerreyes David , Kerr Robert , Fernandeze Asier , Hilder Matthias , Zhang Yafei , Bhutiani Sanshu
Published: February 2020

Sodium batteries are being intensively studied as an alternative for existing Li-ion and more traditional Pb-acid technologies, in particular for stationary energy applications and as safer and cheaper longer term alternatives. As with Li battery technologies, there is intense activity in developing new electrode materials to increase the capacity and energy density of these emerging devices. Electrolyte advances are also critical for improving the safety and performance, enabling high energy density and higher voltage electrodes. We have been developing ionic liquid based electrolytes which enable stable Na metal cycling and demonstrate enhanced cycling stability with a number of cathode materials including NFP, layered oxides, air electrodes as well as supercapacitor carbon based electrodes in ‘hybrid’ devices.[1-5] Surprisingly, we have also recently found that the addition of small quantities of water has been shown to improve the electrochemical performance. Iongels based on a combination of the ionic liquid and various polymers have also been investigated as solid state electrolytes for all solid state batteries. This talk cover our recent work in understanding the structure, transport and electrochemical behaviour of these novel sodium electrolytes and show progress in their application in sodium devices.
(Invited) Working toward a Cost-effective Lithium-ion Battery Recycling Process
Authors: Spangenberger Jeffrey
Published: February 2020

End-of-life lithium-ion batteries in electric and hybrid-electric vehicles are just now starting to reach their end-of-life. The recycling infrastructure that these batteries are expected to go through will likely result as a cost to the end user. Argonne National Laboratory is working to develop, scale-up, and demonstrate, recycle processes that reduce cost and increase revenue to improve the economics of responsible end-of-life lithium-ion battery management even as the use of cobalt is reduced in batteries. Four focus areas are targeted: direct cathode recycling, recovery of other materials, design for recycle, and advanced characterization. This presentation will provide a summary of Argonne’s work to create a profitable battery recycling system.
(Invited) Battery Durability and Reliability Under Electric Utility Grid Operations
Authors: Dubarry Matthieu , Baure George
Published: February 2020

Battery Energy Storage Systems (BESSs) can facilitate renewable energy sources integration onto the grid. For this application, these systems are expected to last for a decade or more, but the actual battery degradation under different real-world conditions is still largely unknown. In this work, three years of lithium titanate BESS usage in Hawai'i were analyzed. In addition, the representative usage was subjected on individual cells under controlled laboratory conditions to study the degradation mechanisms and enable life prognosis.

The BESS was found to be operational 90% of the time and it stored a cumulative 1.5 GWh of energy, which represented more than 5000 equivalent full cycles on the cells. From this BESS usage data, an initial estimate of BESS degradation was provided and a representative duty cycle was developed. The analysis of the maintenance cycles indicated that these 5000 equivalent cycles induced an estimated 5-10% degradation of the single cells. The battery duty cycle was characterized based on 5 parameters: pulses duration, pulses intensity (current), state of charge (SOC) swing range, SOC event ramp rate, and temperature. The average usage consisted of several 9-second C/2 charge and discharge pulses organized to generate 5% SOC swings with a 0.75% SOC/min ramp rate at 35°C. However, extreme values such as currents up to 4C, swings of 100% SOC, and temperatures above 50°C were also recorded.

Laboratory testing and analysis, in conjunction with a more thorough SOH estimation protocol, resulted in a detailed description of degradation that improved the predictions of the remaining useful battery life. Based on the BESS representative usage profile, cycle-aging and calendar-aging experiments were designed to test the degradation of the associated Li-ion cells in a controlled fashion. It was proven that the cell temperature history had the strongest impact on battery degradation followed by the C-rate and the state of charge. Interestingly, the impact of SOC, both on the cycle-aging and the calendar-aging experiments, was revealed to be counterintuitive. During cycle aging, small SOC swings were more detrimental than larger ones. During calendar aging, batteries lost capacity faster at low SOC than at high SOC. The associated degradation mechanisms and their path dependency were analyzed using incremental capacity analysis.
(Invited) Stable and High Conductivity Sodium Superionic Conductors Via Cation Mixing
Authors: Zhu Zhuoying , Ong Shyue Ping
Published: February 2020

All-solid-state sodium-ion batteries utilizing a Na superionic conductor solid electrolyte (SE) are promising candidates for cheap and safe large-scale energy storage. Among the most promising family of Na SEs are the Na3PnS4 (Pn = P, Sb, As) family1–5 and the recently discovered Na11Sn2PnS12 (Pn=P, Sb). 6,7 In this talk, we will present a comprehensive investigation of cation mixing in the Na4TtS4-Na3PnS4 (Tt = Ge, Si, Sn) composition space using first principles calculations. This composition space, which includes Na3PnS4 and Na11Sn2PnS12 as a subset, provides several levers to tune Na concentration and cation types to simultaneously achieve the twin goals of high ionic conductivity and good electrochemical and chemical stability. We will demonstrate that isovalent-mixed Na3Pn’Pn’’S4 compositions have low enthalpies of mixing, indicating that they are likely to be highly miscible. In the aliovalent mixed Na4-xSn1-xPxS4 system, we will show that the experimentally-reported Na11Sn2PS12 prototype with space group I41/acd leads to not only lower formation energies, but also larger 3D diffusion channels. The predicted ionic conductivities from ab initio molecular dynamics simulations are also in excellent agreement with experiments. Finally, we will propose new mixed compositions with potentially higher conductivities and better chemical stability than those already reported experimentally.

Reference:

Hayashi, A., Noi, K., Sakuda, A. & Tatsumisago, M. Superionic glass-ceramic electrolytes for room-temperature rechargeable sodium batteries. Nat. Commun.
3, 856 (2012).

Zhang, L. et al. Na3PSe4 : A Novel Chalcogenide Solid Electrolyte with High Ionic Conductivity. Adv. Energy Mater.
5, 1501294 (2015).

Chu, I.-H. et al. Room-Temperature All-solid-state Rechargeable Sodium-ion Batteries with a Cl-doped Na3PS4 Superionic Conductor. Sci. Rep.
6, 33733 (2016).

Banerjee, A. et al. Na3SbS4 : A Solution Processable Sodium Superionic Conductor for All-Solid-State Sodium-Ion Batteries. Angew. Chemie
128, 9786–9790 (2016).

Zhu, Z., Chu, I.-H., Deng, Z. & Ong, S. P. Role of Na+ Interstitials and Dopants in Enhancing the Na+ Conductivity of the Cubic Na3PS4 Superionic Conductor. Chem. Mater.
27, 8318–8325 (2015).

Zhang, Z. et al. Na11Sn2PS12: A new solid state sodium superionic conductor. Energy Environ. Sci.
11, 87–93 (2018).

Heo, J. W., Banerjee, A., Park, K. H., Jung, Y. S. & Hong, S. T. New Na-Ion Solid Electrolytes Na4-xSn1-xSbxS4(0.02 ≤ x ≤ 0.33) for All-Solid-State Na-Ion Batteries. Adv. Energy Mater.
4, 4–9 (2018).
(Invited) Defect Induced Oxygen Redox Chemistry
Authors: Yamada Atsuo
Published: February 2020

Lithium- and sodium-rich layered transition-metal oxides have recently been attracting significant interest because of their large capacity achieved by additional oxygen-redox reactions. However, layered transition-metal oxides exhibit structural degradation such as layer exfoliation or cracks upon deep charge, which is a major obstacle to achieve higher energy-density batteries. Defect are usually considered as a negative factor to realize stable operation of cathode materials. Here we show, by applying optimal design strategies, defect can not only effectively generate redox-active “orphaned” nonbonding oxygen 2p orbitals to “activate” additional oxygen-redox reactions, but also contribute to “stabilizing” reversible phase transformation with its effective negative point charge.
(Invited) Swelling of Si Nano-Flake Anode for Advanced Lithium-Ion Batteries
Authors: Inaba Minoru , Haruta Masakazu , Doi Takayuki
Published: February 2020

The poor cyclability of Si electrodes is attributed to crack formation and pulverization of Si active material due to a large volume expansion and contraction during charging and discharging, respectively. It is thus important to suppress the physical stress induced by the large volume changes to improve the cyclability of Si electrodes. We designed a Si powder with a flake shape (Si LeafPowderÒ, Si-LP, OIKE & Co., LTD.) with 100 nm in thickness and 3-5 mm in lateral dimension, and have reported that Si-LP electrodes have a high initial discharge capacity (ca. 2,500 mAh g-1) and good cycleability (Fig. 1) [1].

Another serious problem of Si anode is a swelling of the electrode owing to irreversible microstructural changes of Si nano-flakes upon cycling (Fig. 2). The Si-LP sheets in a composite electrode were substantially deformed during alloying/de-alloying cycling and formed the multi-folded layered structure on repeated cycling. Furthermore, many voids, which could accommodate volume changes of Si, were formed on repeated cycling. The multi-folded layered structure with many voids enabled the stable battery operation of the Si-LP electrodes. On the other hand, the thickness of the electrode remarkably increased with cycle number (Fig. 3), which was caused by the deformation of Si-LP sheets and growth of the SEI layer. The electrode swelling was suppressed by the presence of the additives, VC and FEC. The uniform SEI layer formed from the decomposition products of VC or FEC inhibited further decomposition of the electrolyte and suppressed the deformation of the Si-LP sheets. Unfortunately the suppression of the electrode swelling by the additives is not enough, and further suppression of the electrode swelling and/or a new cell design to manage the large volume changes of Si is necessary for practical applications of the Si-LP as a negative electrode in advanced LIBs.

This research was supported by Japan Science and Technology Agency (JST) ALCA-SPRING and Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Number 16H04649.

References

[1] M. Haruta et al., Electrochim. Acta, 267, 94-101 (2018). DOI: 10.1016/j.electacta.2018.02.062

Figure 1
(Invited) 3D Imaging Options of Battery Electrodes
Authors: Lemmens Herman
Published: February 2020

There are different ways to create a 3D image of the battery electrodes. MicroCT uses the absorption of X-rays to create a 3D reconstruction. The Field of View is large enough to be representative with regard to the grain sizes. However, the submicron porosity in the electrodes is typically not well captured by microCT because of its limited resolution.

The FIBSEM technique which uses a Galium ion beam for sectioning and an electron beam for imaging has high enough resolution to resolve all porosity. However, the Field of View is typically of the order of 10 micrometer; which is not always big enough to create a representative model of the pore space.

PlasmaFIB can fill the gap between the Gallium FIB and the microCT on most liquid electrolyte lithium ion cells. However, for some solid state batteries, an even bigger volume is needed. This is where slicing with a laser can be used. In this presentation examples are covered of 3D imaging with microCT, laser sectioning and both Gallium and Plasma FIB.
Polyaniline-Intercalated MnO2 As a High Performance Cathode Material for Zinc-Ion Battery
Authors: Huang Jianhang , Wang Yong-Gang , Xia Yong-Yao
Published: February 2020

Metal-ion batteries based on aqueous electrolyte are attracting widespread attention in the field of large-scale energy storage due to the low cost, high safety and environmental friendliness. However, the development of the most studied aqueous Li+ and Na+ batteries are plagued by the low energy density, which mainly derived from the low capacity of electrode materials (<150 mAh g-1) and the limited voltage window of aqueous electrolyte (<1.8 V). The latter could be conquered by the water-in-salt electrolyte, and the operating voltage > 3V could be obtained1. But the capacity of electrode materials still needs to be enhanced.

Due to the high capacity of metal zinc anode (820 mAh g-1), aqueous Zinc-ion battery based on Zn2+ storage cathode and metal Zn anode holds immense potential to achieve high capacity. But the capacity of cathode still has much room for improvement. As the most used cathode materials for zinc-ion battery, manganese oxides exhibit high theoretical capacity (308 mAh g-1), low cost and low toxicity. Various manganese dioxides, including the α-MnO2, β-MnO2, γ-MnO2, δ-MnO2, etc. have been reported as host materials for Zn2+/H+ insertion in the mild aqueous electrolyte. However, all the crystalline form of manganese oxides undergo structure transformation to layered structure with interlaminar water molecules during zinc-ion insertion, leading to capacity fading of the cell. And the cycling stability of manganese oxides decreases dramatically when cycled at high depth of discharge2.

In this work, we proposed novel polyaniline-intercalated MnO2 nanolayers as a high performance cathode material for zinc-ion battery, which is prepared by a simple one-step inorganic/organic interface reaction3. With the typical nano-size (approximately 10 nm), expanded interlayer space, uniform meso-structure and polymer-reinforced layered structure, the polyaniline-intercalated MnO2 nanolayers show a high rate performance and excellent cycle stability at high charge/discharge depth (200 stable cycles with capacity of 280 mAh g-1, corresponding 90.9% utilization of theoretical capacity of 308 mAh g-1), which is much superior to previous reports. The polyaniline-reinforced layered structure efficiently eliminate the hydrated H+/Zn2+-insertion-induced phase transformation and the subsequent structure collapse, which is important to achieve long cycle life and high utilization simultaneously. In addition, a H+/Zn2+ co-insertion process in the layered MnO2 was proposed, and a self-regulating mechanism of electrolyte involving generation/dissolution of flake-like zinc hydroxide sulfate was clarified.

Reference:

1 C. Yang, J. Chen, T. Qing, X. Fan, W. Sun, A. von Cresce, M.S. Ding, O. Borodin, J. Vatamanu, M.A. Schroeder, N. Eidson, C. Wang, and K. Xu, Joule, 1, 122 (2017).

2 J. Huang, Z. Guo, Y. Ma, D. Bin, Y. Wang, and Y. Xia, Small methods, 1800272 (2018).

3 J. Huang, Z. Wang, M. Hou, X. Dong, Y. Liu, Y. Wang, and Y. Xia, Nature Communications, 9, 2906 (2018).
Operando Capturing the Metastable Phase Formation in Lithium-Rich Layered Oxides
Authors: Yin Wei , Grimaud Alexis , Tarascon Jean Marie
Published: February 2020

Lithium-rich layered oxides (LRLO) have lately emerged as leading candidates for replacing the classical stoichiometric insertion oxides owing to their staggering increase in energy densities provided by the oxygen redox activities.1 Despite such a positive attribute, LRLO still await commercial success due to practical obstacles that appear during the first cycle and continue upon subsequent cycles (i.e., irreversible structural changes associated with oxygen gas release leading to unfavorable electrochemical properties such as hysteresis and progressive voltage decay).2 Though the origin of voltage fade has been discussed from various structural perspectives (i.e., cation capturing through tetrahedral sites, formation of partial dislocations and/or microstructure defects), a consensus has been reached on the strong coupling between structural dynamics and oxygen redox chemistry.3-6 Nonetheless, establishing an explicit structure-properties scenario has proved challenging due to characterization limitations as well as the inherent complexity of the coupled transition metal and oxygen redox process itself. In this work, we investigated both in-situ and ex-situ the structure evolution of a typical Li-rich material during its initial cycles based on a newly developed oxygen analytical tool, laboratory and synchrotron X-ray diffraction (XRD), coupled with electron microscopic imaging technique. The average and local structure change associated with cation migration, gaseous oxygen loss and solid liquid interfacial reactions will be discussed. Furthermore, a metastable phase transformation pathway induced by the lattice oxygen redox activities will be proposed and its implication for the applicability of such Li-rich oxides will be shared.

References:

J. Wang, et al.
Advanced Energy Materials,
6 (21), 1600906 (2016).

G. Assat and J.M. Tarascon, Nature Energy,
3 373-386 (2018).

M. Sathiya, et al.
Nature Materials,
14 230-238 (2014).

A. Singer, et al.
Nature Energy,
3 (8), 641-647 (2018).

E. Hu, et al.
Nature Energy, (2018).

W. E. Gent, et al.
Nature communications,
8 (1), 2091 (2017).
Ni-Rich NCA Cathode with Concentration Gradient for Lithium-Ion Batteries: Li[Ni0.865Co0.120Al0.015]O2
Authors: Park Nam-Yung , Park Kang-Joon , Yoon Dae Ro , Sun Yang-Kook
Published: February 2020

Lithium-ion batteries (LIBs) are considered to be the most promising power sources for electric vehicles (EVs) because of their high energy densities and long cycle lives. However, major impediments for general public acceptance of EVs are their cost, durability, and driving range.1,2 Following the successful application of the hybrid scheme to the NCM cathodes,3-6 we developed a core–shell with concentration gradient Li[Ni0.865Co0.120Al0.015]O2 cathode material (CSG NCA) with a Ni-rich core to maximize the discharge capacity and a Co-rich particle surface to provide structural and chemical stability. Compared to the conventional NCA cathode with a uniform composition, the gradient NCA cathode exhibits improved capacity retention and better thermal stability. Even more remarkably, the gradient NCA cathode maintains 90% of its initial capacity after 100 cycles when cycled at 60 °C, whereas the conventional cathode exhibits poor capacity retention and suffers severe structural deterioration. The superior cycling stability of the gradient NCA cathode largely stemmed from the gradient structure combines with the Co-rich surface, which provides chemical stability against electrolyte attack and reduces the inherent internal strain observed in all Ni-rich layered cathodes in their charged state, thus providing structural stability against the repeated anisotropic volume changes during cycling. The high discharge capacity of the proposed gradient NCA cathode extends the driving range of electric vehicles and reduces battery costs. Furthermore, its excellent capacity retention guarantees a long battery life. Therefore, gradient NCA cathodes represent one of the best classes of cathode materials for electric vehicle applications that should satisfy the demands of future electric vehicles.

References

U.S. Department of Energy, EV Everywhere Grand Challenge Blueprint, 31 January 2013.

S.-T. Myung, F. Maglia, K.-J. Park, C. S. Yoon, P. Lamp, S.-J. Kim, Y.-K. Sun, ACS Energy Lett.
2017, 2, 196.

Y.-K. Sun, S.-T. Myung, B.-C. Park, J. Prakash, I. Belharouak, K. Amine, Nat. Mater.
2009, 8, 320.

Y.-K. Sun, Z. Chen, H.-J. Noh, D.-J. Lee, H.-G. Jung, Y. Ren, S. Wang, C. S. Yoon, S.-T. Myung, K. Amine, Nat. Mater.
2012, 11, 942.

B.-B. Lim, S.-J. Yoon, K.-J. Park, C. S. Yoon, S.-J. Kim, J. J. Lee, Y.-K. Sun, Adv. Funct. Mater.
2015, 25, 4673.

D.-W. Jun, C. S. Yoon, U.-H. Kim, Y.-K. Sun, Chem. Mater.
2017, 29, 5048.
Li/Mn-Rich Layered Transition-Metal Oxides As High-Energy Cathode Materials for Lithium Ion Batteries
Authors: Helbig Jonathan , Schmuch Richard , Naber Verena , Winter Martin , Placke Tobias
Published: February 2020

The class of Li-Mn-rich layered transition metal oxides (LMR-NCM) is one of the most promising candidates for cathode materials in advanced lithium ion batteries (LIBs) due to their high specific discharge capacity of up to 300 mAh/g and specific energy up to 1000 Wh/kg at material level.[1-4] Furthermore, those materials contain a high content of low-cost manganese due to the addition of a Li2MnO3 component compared to standard layered transition metal oxides, which at the same time enables the access of additional capacity. Nevertheless, a strong capacity and voltage fade as well as a poor rate capability plagues the class of LMR-NCM materials. The pronounced reversible oxygen redox activity (causing the voltage hysteresis), the transition metal migration and a phase transition to a spinel-like phase (causing the voltage fade) add to an even stronger fade of the specific energy and inhibit the commercialisation of these cathode materials so far.

To closely study the underlying phenomena, LMR-NCM oxides with different morphologies are synthesized. Therefore, the syntheses via coprecipitation in a Couette-Taylor flow reactor and in a conventional flask are compared. The constant monitoring of critical parameters during the synthesis by means of the reactor leads to dense spherical particles with a narrow particle size distribution. These characteristics offer a spherical cathode material with enhanced capacity retention due to a more compact structure with a lower surface area. Also, taking the voltage fade into consideration allows a more objective evaluation of LMR-NCM oxides materials especially in direct comparison with state-of-the-art NCM-based cathodes.

[1] E. M. Erickson, F. Schipper, T. R. Penki, J.-Y. Shin, C. Erk, F.-F. Chesneau, B. Markovsky, D. Aurbach J. Electrochem. Soc. 2017, 164, A6341 – A6348.

[2] B. Qiu, M. Zhang, L. Wu, J. Wang, Y. Xia, D. Qian, H. Liu, S. Hy, Y. Chen, K. An, Y. Zhu, Z. Liu, Y. S. Meng Nat. Commun. 2016, 7, 12108.

[3] D. Andre, S.-J. Kim, P. Lamp, S. F. Lux, F. Maglia, O. Paschos, B. Stiaszny J. Mater. Chem. A 2015, 3, 6709 – 6732.

[4] T. Placke, R. Kloepsch, S. Dühnen, M. Winter J. Solid State Electrochem. 2017, 21, 1939 – 1964.
A Versatile Polyol Synthesis for Layered, Spinel, and Olivine-Type Cathode Material
Authors: Meng Ying Shirley , Chung Hyeseung , Zhang Minghao
Published: February 2020

One of the most pressing challenges modern society faces is how to provide an energy source for a variety of applications, ranging from small portable devices to electric vehicles (EVs) and a large grid-scale system to store energy from intermittent solar or wind-driven devices. Recently, enough technological advancement has been made that Li-ion batteries (LIBs) are considered as the most promising solution to solve this problem. Over the years, diverse synthetic methods have been developed to synthesize battery cathode materials, such as: solid-state, co-precipitation, sol-gel, hydrothermal, and molten salt syntheses. Each of the synthesis process used to make the cathode oxide material proved to be useful, but simultaneously accompanies some major drawbacks. In the traditional solid-state method, the mixing of multiple metal sources is done by grinding or ball milling. This results in a microcrystalline product with long Li diffusion pathways as well as inhomogeneous morphology and metal distribution. Co-precipitation compensates for some of these shortcomings, but it also requires a careful control of pH in the carbonate method or an inert atmosphere to minimize the undesired impurities in the hydroxide method. Previous studies show that the hydrothermal method is an effective way to synthesize cathode material with high crystallinity, but it requires a complex experimental set up which utilizes a stainless steel autoclave to withstand high vapor pressure during its lengthy reaction time. Furthermore, all the methods require a long post annealing process, typically lasting more than 12 hours at high temperature (>800ºC).

Herein, we developed a novel polyol synthetic process to prepare the most promising cathode materials in layered, spinel, and olivine structure. Developed by Fievet group in 1985, polyol-mediated synthesis has been widely used for the past decades, but its scope has been mostly limited to the synthesis of metals and metal oxides. In this work, our group has extended this synthesis method to develop more complex metal oxide used for battery cathode materials. All three of the synthesized materials are monodispersed nanoparticles with dispersive morphology and competitive electrochemical performance. Using a combination of powder x-ray diffraction (XRD), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and energy dispersive spectroscopy (EDS), we also confirmed its high crystallinity and uniform elemental distribution for all three polyol-synthesized cathode materials. Finally, HAADF-STEM image and electron energy loss spectroscopy (EELS) for cycled NMC material was analyzed to confirm its structural stability even after charge-discharge process. We anticipate that these findings lead to the plethora of new cathode materials that can be explored using this synthetic method.

Figure 1
Mastering the Anode/Electrolyte Interphase Reactivity with Slight Surface Fluorination
Authors: Charles-Blin Youn , Flahaut Delphine , Monconduit Laure , Louvain Nicolas , Guerin Katia , Dubois Marc , Ledeuil Jean-Bernard , Martinez Hervé
Published: February 2020

In secondary batteries, the anode/electrolyte interphase plays a key role in the electrochemical performances. As the liquid organic electrolyte undergoes degradation in the electrochemical potential window of a cycling battery, a Solid Electrolyte Interphase (SEI) is formed upon cycling. This interphase layer leads to a double-edged problematic: the formation of the SEI lowers the coulombic efficiency and causes irreversible capacity loss, but it also passivates the electrode from the electrolyte and prevents further aging processes. Knowing this, any modification of the SEI should be performed with parsimony as it could break the balance between the positive and negative aspect of the SEI. By synthetizing a chemisorbed thin fluorinated layer upon anode material, we managed to improve the passivating power of the SEI leading to enhanced electrochemical performances. We also determine that very low quantities of fluorine on the active electrode material surface leads to several beneficial effects.

The chemical nature of the surface layer was describe by the mean of the XPS (figure 1), as well as the fluorine distribution on the surface with both AES and SAM. The fluorine has been quantified around 10 at. % of the extreme surface of the Li4Ti5O12 (LTO) material, without diffusion in particles bulks. The bulk and sub-surface properties of fluorinated LTO (LTO-F) were also investigated by coupling XRD, Raman Spectroscopy and NMR 19F, showing no modifications of the crystallographic structure. The influence of the surface fluorination on the electrochemical performance was investigate by galvanostatic cycling and by coupling XPS and SAM on cycled electrodes. We had a specific attention to the impact of the fluorination on the SEI thickness and stability in charge and discharge. Indeed, LTO-F exhibit a new reactivity toward the electrolyte, leading to a thinner and stabilized SEI. Finally, the gas generation of the LTO-F electrodes has been investigate by Gas Chromatography – Mass Spectrometry (GC-MS), as gassing is known to be a roadblock to the commercialization of LTO1,2. We demonstrate that the CO2 outgassing is reduced by the surface fluorination. The strategy implemented in this work, from synthesis to thorough characterization, allow to propose new solutions to improve SEI for Lithium ion batteries.

(1) He, Y.-B.; Li, B.; Liu, M.; Zhang, C.; Lv, W.; Yang, C.; Li, J.; Du, H.; Zhang, B.; Yang, Q.-H.; et al. Gassing in Li(4)Ti(5)O(12)-Based Batteries and Its Remedy. Sci. Rep.
2012, 2, 913.

(2) Zhang, L.; Zhang, S.; Zhou, Q.; Snyder, K.; Miller, T. Electrolytic Solvent Effects on the Gassing Behavior in LCO||LTO Batteries. Electrochimica Acta 2018, 274, 170–176.

Figure 1
Suppression of Voltage Decay through Manganese Deactivation and Nickel Redox Buffering in High-Energy Layered Lithium-Rich Electrodes
Authors: Ku Kyojin , Hong Jihyun , Kim Hyungsub , Park Hyeokjun , Seong Won Mo , Jung Sung-Kyun , Yoon Gabin , Park Kyu-Young , Kim Haegyeom , Kang Kisuk
Published: February 2020

Cobalt-free layered lithium-rich nickel manganese oxides, Li[LixNiyMn1−x−y]O2, are promising positive electrode materials for lithium rechargeable batteries because of their high energy density and low materials cost. Utilization of the oxygen anionic redox in this series of materials enables realization of a high capacity beyond that achieved via the conventional transition metal cationic redox when charging above 4.5 V vs. Li/Li+. However, substantial voltage decay is inevitable upon electrochemical cycling, which makes this class of materials less practical. The undesirable voltage decay has been proposed to be linked to irreversible structural rearrangement involving irreversible oxygen loss and cation migration. Herein, we demonstrate that the voltage decay of the electrode is correlated to the activation of Mn4+/Mn3+ redox and subsequent cation disordering, which is able to be remarkably suppressed via simple compositional tuning to induce the formation of Ni3+ in the pristine material. By implementing our new strategy, an alternative redox reaction involving the use of this pristine Ni3+ as a redox buffer, which has been designed to be widened from Ni3+/Ni4+ to Ni2+/Ni4+, subdued the Mn4+/Mn3+ reduction without compensation for the capacity in principle. Negligible change in the voltage profile of the modified lithium-rich nickel manganese oxide electrode is observed upon extended cycling, and manganese migration into the lithium layer is significantly suppressed. Based on these findings, we propose a general strategy to suppress the voltage decay of Mn-containing lithium-rich oxides to achieve long-lasting high energy density from this class of materials.
Fluoride Shuttle Batteries by Liquid Electrolytes
Authors: Kawasaki Mitsuo , Morigaki Ken-ichi , Kano Gentaro , Abe Takeshi , Ogumi Zempachi
Published: February 2020

Rechargeable batteries with fluorides as charge transporting ions, which we refer to as fluoride shuttle butteries (FSBs, see Fig. 1), potentially offer a high electrochemical energy storage capability that overwhelms those of the state-of-the-art lithium-ion batteries (LIBs). This is due to the unique properties of monovalent fluoride ions, which are lightest of halides, hardly oxidized, and yet capable of reacting with various metals to form mono- and multi-valent fluoride salts. They thus allow anion-based, multi-electron transfer, redox reactions under wide potential window. Besides, FSBs as such no longer require host lattices (prerequisite in LIBs), which further adds to the high energy density.

The fundamental concepts and some successful examples of FSB systems that had been developed in the RISING battery project were addressed by one of the present co-authors (Z. Ogumi) in IBM2017 and IBA2018. We here focus on the recent advance in liquid-type FSBs that came out through the continued RISING2 battery project. It should be noted that none of alkali fluorides are soluble in common buttery-oriented organic solvents no matter how large static dielectric constants they have. Used as alternative electrolytes have thus typically been organic fluoride salts (such as alkylammonium or substituted alkylammonium fluorides) in combination with preferably ionic liquids. Another, more-or-less sophisticated, way out is to utilize so-called anion receptors that make even alkali fluorides substantially soluble in common organic solvents.

We here show nonaqueous plain liquid fluoride electrolytes, which, according to our comprehensive and careful analyses, are apparently free from any addenda but somehow solvated Cs+ (or K+) cations and F- anions at a molar concentration of ~50 mM to give total ionic conductivity of typically ~0.8 mS/cm. The simple electrolytes exhibit versatile performance to make a variety of combinations of electrodes (ranging from Au/AuF3 to at least Zn/ZnF2) work reversibly in terms of the expected conversion reaction between the respective metal and its fluoride counterpart.

Acknowledgement

This work was supported by the Research and Development Initiative for Scientific Innovation of New Generation Battery 2 (RISING2), financially supported by New Energy and Industrial Technology Development Organization (NEDO).

Figure 1
Failure Mechanism of Lithium Metal Battery from the Aspect of Solvent and Salt Decomposition
Authors: Guo Juchen , Zhang Jian
Published: February 2020

Lithium metal has been regarded as the most promising anode material for future high energy density lithium ion battery due to its high theoretical capacity (~3860mAh/g) and the lowest electrochemical potential (-3.04V vs the standard hydrogen electrode). The limitations for lithium metal to be the ideal anode are mainly the uncontrollable dendritic lithium growth and low coulombic efficiency. This work uses the lab-made fresh thin lithium foil with the thickness of 50 µm to eliminate the thickness influence on cycle life. The following research mainly focus on understanding the failure mechanism of lithium metal anode from aspect of salt and solvent in electrolyte. Two and three electrode symmetric lithium metal coin cells were made using different electrolyte (lithium hexafluorophosphate –LiPF6, Lithium bis(trifluoromethanesulfonyl)imide –LiTFSI and Lithium bis(trifluoromethanesulfonyl)imide – LiFSI in Ethylene Carbonate and Diethyl Carbonate with volume ratio 50:50) with different concentration to test long cycle stability. The cycle life data shows the decreasing cycle life with the increasing mole concentration of LiFSI and LiTFSI electrolyte, while the cycle life of the cells using LiPF6 electrolyte increases when using higher concentration. We believe both solvent and salt decomposition reactions influence the composition of Solid Electrolyte Interphase – SEI on lithium metal when cycling. Fourier-transform infrared spectroscopy (FTIR) and Nuclear magnetic resonance (NMR) will be used to realize the decomposition product of solvent and X-ray photoelectron spectroscopy (XPS) will be used to figure out the salt decomposition product. The evidence of lithium dendrite pierce the separator has been found by using Focused Ion Beam (FIB) with Scanning Electron Microscopy (SEM). Also the thickness of dead lithium will growth with cycles to fulfill the available space in the cells. Both coin cells and Electrochemical Quartz Crystal Microbalance (EQCM) were made to calculate the columbic efficiency by using different electrolyte mentioned above. Electrochemical impedance spectroscopy (EIS) was used to analysis the SEI and charge transfer resistance change during cycles to identify which part mostly contribute the overpotential. In this work, we will figure out the decomposition reactions of solvent and salts to analysis the failure mechanism.
Diagnostic Tools and Safety Aspects of Aged Commercial Li-Ion Batteries
Authors: Vie Preben J. S. , Maehlen Jan Petter , Lian Torleif , Forseth Sissel , Andersen Hanne Flåten
Published: February 2020

The degradation and ageing of Li-ion batteries will in many cases contribute to reduced thermal stability which potentially affects the safety performance of the batteries. The fact that aging of lithium-ion cells leads to a reduced capacity and cell life, is extensively covered in the literature by several research groups, e.g. Vetter[1]. The safety effects of ageing are far less studied, with only a handful of empirical studies published, e.g. [2-4].

This poster presents ageing data and safety aspects of large commercial Li-ion cells. The cells have been aged and cycled at 5, 25 and 45 °C. Several diagnostic tools have been applied to characterise the ageing mechanisms. These tools include high power pulse characterisation, entropy spectroscopy, incremental capacity analysis and impedance spectroscopy.

The ageing mechanisms are however different at low and high temperatures and this will affect the thermal stability of the aged cells. The thermal stability of cells which have been aged with different ageing mechanisms was characterized with an Accelerated Rate Calorimeter (ARC). It was e.g. observed that a cell cycled at 5 °C for 3000 cycles reaching 70% State-of-Health showed a reduced thermal runaway limit from 240 to 150 °C compared to the uncycled cell. This was also lower than the exotherm onset temperature for the uncycled cell.

References

Vetter, J., et al., Ageing mechanisms in lithium-ion batteries. Journal of Power Sources, 2005. 147(1-2): p. 269-281.

Fleischhammer, M., et al., Interaction of cyclic ageing at high-rate and low temperatures and safety in lithium-ion batteries. Journal of Power Sources, 2015. 274: p. 432-439.

Gilljam, M., et al., 7E. Effect of electrical energy and aging on cell safety, in Safety of Lithium Batteries, J. Garche and K. Brandt, Editors. 2017, Elsevier.

Friesen, A., et al., Influence of temperature on the aging behavior of 18650-type lithium ion cells: A comprehensive approach combining electrochemical characterization and post-mortem analysis. Journal of Power Sources, 2017. 342: p. 88-97.
Temperature Influence on Silicon-Based Anodes for Li-Ion Batteries
Authors: Piernas-Muñoz María José , Trask Stephen E. , Dunlop Alison R , Bloom Ira
Published: February 2020

Environmentally friendly hybrid, plug-in hybrid and full-electric vehicles (EVs) are gaining importance [1]. However, to gain further acceptance by the consumer, it is essential to extend the autonomy range of EVs to be similar to that of a gasoline-fueled car. There is a need for finding next-generation lithium-ion batteries (LIBs) with larger specific capacity and, therefore, higher energy density.

Undoubtedly, one of the most direct strategies to boost the specific capacity of LIBs is to replace the widely used graphite anode with other materials capable of delivering much larger capacities.[2] Among potential candidates, silicon is one of the most promising anode materials, since it offers a theoretical capacity (~3579 mAh/g) approximately 10 times higher than that of graphite (~370 mAh/g) [3], [4]. Besides, silicon is the second most abundant element in the earth’s crust, which positions it as a commercial-friendly substitute of carbon materials for anodes of LIBs[5]. Nevertheless, silicon anodes display pronounced capacity fade upon cycling and, thus, presents a great challenge to battery design 3
,
4
,
5.

Another aspect that so far has not been considered nor explored is the influence that temperature would have over the cyclability of silicon anodes in LIBs. To understand its effect, we performed galvanostatic experiments at different temperatures with silicon-based anodes in half-cells. In addition, the effect of using fluoroethylene carbonate (FEC) as an additive was also investigated. The different capacity fading observed and the possible kinetic mechanisms behind that distinct behavior will be discussed here.

We gratefully acknowledge support from the U. S. Department of Energy (DOE), Vehicle Technologies Office. Argonne National Laboratory is operated for DOE Office of Science by UChicago Argonne, LLC, under contract number DE-AC02-06CH11357.
The U.S. government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the government.

[1] M. Armand and J-M. Tarascon. Nature 2008, 451, 652-657. Building better batteries.

[2] V. Etacheri, R. Marom, R. Elazari, G. Salitra and D. Aurbach. Energy Environm. Sci. 2011, 4, 3243-3262. Challenges in the development of advanced Li-ion batteries: a review.

[3] X. Su, Q. Wu, J. Li, X. Xiao, A. Lott, W. Lu, B. W. Sheldon and J. Wu. Adv. Energy Mater. 2014, 4, 1300882. Silicon-Based Nanomaterials for Lithium-Ion Batteries: A Review.

[4] H. Wu and Y. Cui. Nanotoday 2012, 7(5), 414-429. Designing nanostructured silicon anodes for high energy lithium ion batteries.

[5] U. Kasavajjula, C. Wang and A. J. Appleby. Journal of Power Sources 2007, 163, 1003. Nano- and bulk-silicon-based insertion anodes for lithium-ion secondary cells.
Synergistic Effect of Cycling Strategies and Electrolyte for Effective Plating/Stripping of Anode Free Li Metal Batteries.
Authors: Beyene Tamene Tadesse , Su Wei-Nien , Dai Hongjie , Hwang Bing-Joe
Published: February 2020

Anode-free batteries (AFBs) are impressive and recent phenomena in the era of energy storage devices due to their high energy density and relative ease of production. However, dendrite formation during plating and stripping and low coulombic efficiency (CE) are the main challenges that impede practical implementation of these batteries. Here we report an extremely stable dual-salt electrolyte, 2M LiFSI+1M LiTFSI (2FSI+1TFSI)) in DME-DOL (1:1, v/v), system in comparison to the single salt 3M LiTFSI (3TFSI) in DME-DOL (1:1, v/v), to effectively stabilize AFB composed of LiFePO4 (LFP) cathode and bare Cu-foil anode for the first time. The electrolyte stabilized anode-free cell with the configuration Cu||LFP via reductive decomposition of its anions and enabled the cell to be cycled with CE of 98.9% for more than 60 cycles, which by far exceeds all the few reports in this field using other kinds of electrolytes. This results from formation of stable, ion conductive inorganic components rich Solid Electrolyte Interface (SEI) layer on the surface of in-situ formed Li-metal that prevent its direct contact with the electrolytes and hence intercepts undesirable parasitic reaction between Li and the electrolyte. Thus aforesaid SEI formed from reductive decomposition components of the dual-salt mitigates formation of dead lithium and dissolution of the in-situ formed Li surface during repeated cycling and prolongs cycle life of the battery.
Dilution Effects of Highly Concentrated Carbonate Ester-Based Electrolyte Solutions for LiNi0.8Co0.1Mn0.1O2 Positive-Electrode
Authors: Cao Ziyang , Hashinokuchi Michihiro , Doi Takayuki , Inaba Minoru
Published: February 2020

A LiNi0.8Co0.1Mn0.1O2 positive-electrode exhibits a high initial discharge capacity of ca. 200 mAh g-1 by charging up to 4.3 V
vs
. Li/Li+
[1]. However, the cycle performance is poor in conventional electrolyte solutions due to the oxidative decomposition of the electrolyte at such a high potential. In our previous work, the charge/discharge cycle performance of LiNi0.8Co0.1Mn0.1O2 was greatly improved in the nearly saturated 8.67 mol kg-1 LiBF4/dimethyl carbonate (DMC) electrolyte solution, which has low DMC/Li molar ratio of 1.28. Unfortunately, the high viscosity and low ionic conductivity restrict its practical use. In this work, we applied fluorinated ester, i.e. methyl 3,3,3,-trifluoropropionate (FMP), as a diluent to decrease the viscosity. Then, we replaced a part of DMC in LiBF4/DMC+FMP with propylene carbonate (PC) to improve its stability against oxidation. LiNi0.8Co0.1Mn0.1O2 showed excellent cycle durability in the resultant ternary system of LiBF4/PC+DMC+FMP electrolyte solution.

The slurry consisted of 80 wt% LiNi0.8Co0.1Mn0.1O2 powder, 10 wt % carbon conductive agents (Ketjenblack) as a conductive additive, and 10 wt % polyvinylidene fluoride (PVdF) as a binder in an N-methyl-2-pyrrolidone (NMP) was coated onto Al foil. The sheet was dried at 80 ℃ for 18 h under vacuum, and punched into 13 mm diameter discs. Then, the disc electrodes were used to assemble two-electrode coin-type cells with Li foil as a counter electrode. The electrolyte solutions used in this study were 2.5 mol kg-1 LiBF4/DMC+FMP (1:2 by volume, DMC/Li=1.28, 11.4 mPa s) and 2.5 mol kg-1 LiBF4/PC+DMC+FMP (1:3:8 by volume, PC+DMC/Li=1.28, 14.5 mPa s). Li|LiNi0.8Co0.1Mn0.1O2 half-cells were prepared by using these electrolyte solutions and cycled galvanostatically at 0.1 C (1 C=275 mAh g-1) between 3.0 and 4.3 V at 30oC.

In 2.5 mol kg-1 LiBF4/DMC+FMP, the discharge capacity decreased to 88.0 % of the initial one in 50 charge/discharge cycles. On the other hand, 96.5% of the initial discharge capacity (195 mAh g-1) was maintained even at the 50th cycle in 2.5 mol kg-1 LiBF4/PC+DMC+FMP. The average coulombic efficiency (99.6 %) in the 50 cycles was higher than that obtained for 2.5 mol kg-1 LiBF4/DMC+FMP (99.5%). The Raman spectra suggests that adding FMP to dilute the saturated LiBF4/DMC has damage to the solvate structure and leads to the increase of free solvate. However, the PC+DMC+FMP-based electrolyte solution is stabilized against oxidation by forming aggregates (AGGs) [2], which should result in improvement of charge/discharge cycle performance of LiNi0.8Co0.1Mn0.1O2 positive-electrode.

References
:

[1] Y. Bi
et al
.,
J.

Power Sourc

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, 283 (2015) 211–218.

[2] T. Doi
et al
.,
Sustainable Energy Fuels
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Deposition and Stripping Behavior of Lithium Metal in Electrochemical System: Continuum Mechanics Study
Authors: Yoon Gabin , Moon Sehwan , Ceder Gerbrand , Kang Kisuk
Published: February 2020

Metallic lithium (Li) is a promising anode candidate for high-energy-density rechargeable batteries because of its low redox potential and high theoretical capacity. However, its practical application is not imminent because of issues related to the dendritic growth of Li metal with repeated battery operation, which presents a serious safety concern. Herein, various aspects of the electrochemical deposition and stripping of Li metal are investigated with consideration of the reaction rate/current density, electrode morphology, and solid electrolyte interphase (SEI) layer properties to understand the conditions inducing abnormal Li growth. It is demonstrated that the irregular (i.e., filamentary or dendritic) growth of Li metal mostly originates from local perturbation of the surface current density, which stems from surface irregularities arising from the morphology, defective nature of the SEI, and relative asymmetry in the deposition/stripping rates. Importantly, we find that the use of a stripping rate of Li metal that is slower than the deposition rate seriously aggravates the formation of disconnected Li debris from the irregularly grown Li metal. This finding challenges the conventional belief that high-rate stripping/plating of Li in an electrochemical cell generally results in more rapid cell failure because of the faster growth of Li metal dendrites.

Figure 1