bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of Dual-Salt Electrolytes for Rechargeable Lithium Metal Batteries
Authors: Jiao Shuhong , Zheng Jianming , Cartmell Samuel , Zhang Ji-Guang , Xu Wu 
Published: February 2020

Rechargeable Li metal batteries have been extensively studied over the past 40 years due to an increasing need for high energy batteries. Lithium metal is an ideal anode material for rechargeable batteries, because of its extremely high theoretical specific capacity (3,860 mAh g-1), the lowest negative electrochemical potential (-3.040 V vs. the standard hydrogen electrode) and a low gravimetric density (0.534 g cm-3). However, there are still tremendous challenges hampering its practical applications owing to many issues, such as Li dendrite growth and low Coulombic efficiency during charge/discharge processes are key problems that need be solved. Uncontrollable dendritic Li growth and limited Coulombic efficiency could lead to short cycling life and safety hazards because of potential internal short circuits.
In this work, we will demonstrate a variety of strategies for Li anode protection to improve its Coulombic efficiency and extend the cycling lifespan in traditional Li-ion battery electrolytes. The highly-efficient electrolyte compositions for Li metal batteries will be developed, optimized and evaluated, and especially the dual salt electrolyte system will be thoroughly investigated to dig out a deep understanding of the relationship between electrolyte recipe, solid-electrolyte interphase (SEI) and cell performance. Also, the solvent effect on the stable cycling of Li anode will be explored and discussed. The optimized electrolyte will be evaluated in the Li||LiNi1/3Mn1/3Co1/3O2 (NMC) coin cells with an NMC areal loading of 2.8 mAh cm-2. In addition, the temperature effect on the electrolyte stability in the cells will be studied. Details of the studies will be reported and discussed in the presentation.
Transport Phenomena of Nonaqueous Electrolyte Solutions at High Concentrations: A Comparison Between the Li- and Na-Systems
Authors: Kuratani Kentaro , Kishimoto Iori , Nishida Yasuhiro , Kondo Ryota , Takeshita Hiroyuki T , Senoh Hiroshi , Kiyobayashi Tetsu 
Published: February 2020

In order to understand the solution chemistry of electrolyte solutions at concentrations far from infinite dilution, the solution density, viscosity and ionic conductivity of Li- and Na-TFSI dissolved in GBL and PC were measured at 0.1 ≤ C/mol·dm−3 ≤ 2.0 and 278 ≤ T/K ≤ 328 (TFSI = bis(trifluoromethanesulfonyl)imide, GBL = γ-butyrolactone and PC = propylene carbonate). The partial molar volume of the solute, derived from the density, confirmed that the Na-systems occupy more volume in the solution than the Li-systems. On the other hand, the viscosity and ionic conductivity suggested that the Na-systems are more fluid and conductive than the Li-systems. The relative viscosity vs. the molarity follows a modified empirical Jones-Dole equation. The molar conductivity linearly decreased with respect to the cube-root of the molarity, which was analyzed by the pseudolattice model. The Raman spectroscopy revealed that, while the solvation number is comparable at 1-2 for either the Li- or Na-systems, Li+ is more tightly bound to the solvent molecules than Na+. The higher fluidity and conductivity of the Na-systems than those of the Li-systems result from the less occurrence of the solvent-shared ion pairs in the former than in the latter.
Reference: K. Kuratani et al., J. Electrochem. Soc., 163 (6) H417-H425 (2016)
Interfacial Lithium-Ion Transfer Between Graphite Negative Electrode and Sulfide Solid Electrolyte
Authors: Huang Meiqi , Fukutsuka Tomokazu , Miyazaki Kohei , Hayashi Akitoshi , Tatsumisago Masahiro , Abe Takeshi 
Published: February 2020

Introduction

All-solid-state lithium secondary batteries using inorganic solid electrolytes instead of liquid electrolytes have been expected as next-generation secondary batteries with high safety and high reliability. Among the inorganic solid electrolytes, sulfide-based solid electrolyte such as Li2S-P2S5 based glass solid electrolyte has received much attention due to the high lithium-ion conductivities and room temperature pressure sintering [1]. Graphite has been used as the negative electrode materials in commercial lithium-ion batteries, and the improvement in interfacial lithium-ion transfer reaction between graphite and liquid electrolyte is recognized as an important issue and this issue should be considered in all-solid-state lithium secondary batteries. In this study, interfacial reaction between graphite and sulfide solid electrolyte was investigated.

Experimental

A layered electrolyte consists of 75Li2S-25P2S5 glass pellet and 1 mol dm-3 LiClO4/propylene carbonate (PC) was used in order to use lithium metal electrode as reference electrode. A three-electrode cell was assembled by using graphite sheet as working electrode, lithium metal as counter and reference electrodes. Cyclic voltammetry and electrochemical impedance spectroscopy were carried out.

Results

Figure 1 shows the cyclic voltammogram of the three-electrode cell using graphite sheet as working electrode. An oxidation-reduction current was observed between 0 – 0.5 V (vs. Li/Li+). Since lithium ion cannot intercalate into graphite sheet in LiClO4/PC, this oxidation-reduction peak indicates that lithium-ion intercalation/de-intercalation proceeded at the interfacial between graphite sheet and 75Li2S-25P2S5 glass pellet. In the Nyquist plot, one semi-circle was observed and assigned to interfacial lithium-ion transfer process. In the meeting, the activation energy for the interfacial lithium-ion transfer process will be discussed.

Reference

[1] A. Sakuda et al., Sci.
Rep., 3, 2261 (2013).

Acknowledgement

This work was financially supported by ALCA-SPRING of the JST.

Figure 1
Impact of Proton Contamination on the Solid Electrolyte Li7La3Zr2O12 (LLZO)
Authors: Yu Seungho , Siegel Donald J 
Published: February 2020

Inorganic solid-state electrolytes are receiving attention due to the safety issues associated with flammable organic liquid electrolytes used in modern Li-ion batteries. Solid electrolytes can also enable higher energy density batteries by allowing use of metallic anodes. Li7La3Zr2O12 (LLZO) is one of the most promising solid electrolytes due to its high ionic conductivity (∼1 mS/cm), wide electrochemical window, and stability with respect to lithium. However, recent experimental evidence suggests that LLZO is unstable when exposed to humid air, resulting in proton exchange with lithium in the bulk and surface carbonation preceded by hydration (LiOH formation).1 Here, first principles calculations were used to investigate the reaction thermodynamics for surface hydration and carbonation of LLZO. Furthermore, ab-initio molecular dynamics (AIMD) were performed to examine the effect of proton substitution on diffusion within the Li sublattice. AIMD calculations indicate that moderate levels of protonation (up to ~10% H+ substitution) results in only a minor decease in Li-ion conductivity. On the other hand, higher proton concentrations can limit this conductivity significantly.
[1] G. Larraz, A. Orera and M. L. Sanjuan J. Mater. Chem. A, 1, 11419 (2013)
Stable Cyclability of Novel Triblock Polyelectrolyte Separators for Lithium Metal Battery
Authors: Liu Kun Lin , Chao Chi Yang 
Published: February 2020

Lithium metal is a promising anode for next generation lithium batteries due to its high theoretical energy density (3860mAh g-1). However, despite the attractive feature of lithium metal, its dendrite could form short circuit inside the cells and cause serious safety problems during lithium plating and stripping process. Polymer electrolyte with high lithium transference number and high modulus would substantially mitigate dendrite growth in lithium metal battery. According to previous models, structuring the electrolyte to immobilized the anions with high shear modulus is of the various options to suppress dendrite growth. In this work, we designed a single-ion conductor (SIC) based on a block copolymer using sulfonic anion, whose structure covalently bonded with hydoxylated polyisoprene (named as sPI) to reach high transference number. Polystyrene can be used to support the mechanical properties of matrix and the adjacent polyisoprene with double bond main chain plays a decoupling role (PI(1,4)) which separate the stiff PS domain, and the lithium conducting sPI domain (referred to SII block copolymer).
Using small angle X-ray scattering and transmission electron microscopy, nanostructures of membranes were identified as a bi-continuous network structure. Remarkably, the maximum conductivity was 1.4×10-4 S cm-1 at ambient temperature with merely 30 wt% solvent uptake. The lithium transference number (TLi
+) was nearly unity in liquid electrolyte. The Young’s modulus of SII was 53 MPa and storage modulus was nearly 3 GPa at room temperature. This bi-continuous morphology with high TLi
+, high modulus, and moderate conductivity is believed to suppress dendrite grow effectively. From galvanostatic cycling experiments, we found that the presence of PS and the sPI in SII membrane in liquid electrolyte with lithium symmetric cell provides over 245 hr in cell life time. Batteries containing SII membranes in liquid electrolyte are able to cycle at least 20 times with high coulombic efficiency (98%). This results warrant that the sPI can effectively delay lithium dendrite formation due to reduced uneven lithium deposition while maintaining the mechanical property with moderate values by adjusting PS and PI(1,4) length, and this architecture design also made the application of SIC in lithium metal polymer battery possible in the future.
Effects of an Organic Chemical Additive in Electrolyte on the Suppression of Lithium Dendrite in Lithium Metal Based Batteries
Authors: Ho Van-Chuong , Ngo Duc Tung , Le Hang T.T. , Kim Su-Won , Park Chan-Jin 
Published: February 2020

Lithium (Li) metal has attracted much attention as an anode material for high energy density batteries due to the high theoretical specific capacity and low negative electrochemical potential of Li. However, the growth of Li dendrite on the metal electrode surface can lead to short circuits during the repeated electrochemical discharge-charge cycles. The control of lithium dendrite is one of the greatest challenges hindering the successful development of Li metal based batteries. In particular, Li metal is generally unstable against most chemical species and reacts with organic solvents as well as salts in liquid electrolyte. Furthermore, repeated stripping and deposition of Li may induce the uncontrolled dendritic growth of Li.
To overcome aforementioned obstacles and difficulties in Li metal anode, we propose the use of an organic chemical as an electrolyte additive for controlling Li dendrite. The base electrolyte of LiTFSI/TEGDME was used for tests. With the addition of the additive, the Li grains formed, while the fiber-like Li dendrite formed in the Li/Li symmetric cell without the additive in electrolyte. Furthermore, the uniform solid electrolyte interphase (SEI) layer formed by the addition of the organic additive, leading to the suppression of Li dendritic growth and electrolyte decomposition. Accordingly, the Li/Li symmetric cell containing the additive operated for longer than 700 cycles, which was four time longer than that of symmetric cell without additive in the electrolyte, under the current density of 0.1 mA cm-2 when the areal capacity was limited to 0.2 mAh cm-2. Under the limited areal capacity of 1 mAh cm-2 at the current density of 0.5 mA cm-2, the cell containing the additive maintained the cycle life longer than 350 h. Further development of this electrolyte additive may enable the practical applications in Li metal based batteries such as Li-air battery.
Li Insertion and Removal Potentials of Li7P3S11 Using VASP Calculation
Authors: Doh Chil-Hoon , Ha Yoon-Cheol , Lee You-Jin , Park Jun-Woo 
Published: February 2020

Study on Li7P3S11 material was carried out by ab initio calculation. using the Vienna ab initio Simulation Package (VASP)[1]. Li7P3S11 was known as a super-ionic conductor (5.4 mS/cm at 25℃) to be a solid-electrolyte of all-solid-state lithium batteries. Two different crystal structure of Li7P3S11 were reported by Onodera (2010) and Tatsumisago (2007) with slight difference on atomic positions. Between total energies of VASP calculation on two structures, Tatsumisago’s structure had slightly more stable energy (Etotal –92.573 eV). Among Li7P3S11, Li3PS4, Li4P2S6 and Li4P2S7, the formation potential of Li7P3S11 was the highest value of 2.216 V(Li/Li+) to be the most stable material. Chemical reactivity of Li7P3S11 material toward moisture to be Li7P3O11 had the reaction energy of –0.34 eV. Li+ conduction of Li7P3S11 take place through vacancy and interstitial diffusion pathways. Xiong (2014) reported on the formation potential of Li7-1P3S11. Here, the formation potential of Li14-xP6S22 (x= 1~14) were evaluated briefly through a stepwise removal of Li+ from Li14P6S22 to Li0P6S22 to be a range of 3.2 ~ 2.6 V. Formation potentials of Li14+1P6S22 were also evaluated for four different interstitial sites. Site(III) denoted at Xiong’s report had 0.643 V(Li/Li+) to be the most easy accommodation of Li+ ion. Patterns of the total density of states (TDOS) of Li14+xP6S22 (x=1,0,-1) were not so different and shown ~3.5 eV by the Hyed-Scuseria-Ernzerhof (HSE) hybrid functional and ~2.1 eV by GGA to be electronic insulator.
[1] Kresse,G.; Hafner, J. Phys. Rev. B, 47 (1993) 558; 49 (1994) 14251.

Figure 1
DFT Molecular Dynamics Simulations of Li+
Authors: Leclerc Nima , Adelstein Nicole 
Published: February 2020

INTRODUCTION
Using first principle Density Functional Theory (DFT) simulations of both the crystalline and amorphous phases of β-Li3PS4, the cause of high conductivity of Li+ ions in the amorphous phase is explored. β-Li3PS4
and other lithium thiosulphates are promising electrolytes for all solid-state batteries, even in their amorphous phases. However, the high conductivity in the amorphous phase is not understood. This research aims to predict conductivity in amorphous electrolytes by comparing diffusion in the crystalline and amorphous phases of a known conductor.
METHODOLOGY
This project uses first principle DFT simulations to simulate diffusion paths in the β-Li3PS4 solid electrolyte and its amorphous analog. These simulations are done using the planewave DFT in the Quantum ESPRESSO[1] package, with a 128 atom supercell for the crystalline phase and a 640 atom amorphous electrolyte. By varying different factors such as, cell volume and temperature and lattice disorder, we were able to compare and understand the diffusion of Li+.
RESULTS and DISCUSSION
In this research, we aim to improve conductivity in amorphous and crystalline electrolytes by simulating the lithium ion diffusion pathways in lithium thiophosphates. The structure of the unit cell is shown in Fig. 1
[2]
. The data is analyzed to identify the following effects on lithium ion diffusion:

Covalent-type bonding between Li+ and the anion sub-lattice

The disorder within the cell, from local disorder to the full amorphous phase

Lithium ion motion correlations

The results presented will be molecular dynamics of both amorphous and crystalline structures of β-Li3PS4. Comparison of local structure and diffusion pathways in the amorphous and crystalline phase, in particular the effect of covalent bonding and correlated Li+ motion.

[1] P. Giannozzi, et al J.Phys.:Condens.Matter, 21, 395502 (2009) http://dx.doi.org/10.1088/0953-8984/21/39/395502 . (BibTeX format).
[2] VMD- Visual Molecular Dynamics. Computer software. Theoretical and Computational Biophysics Group. Vers. 1.9.2. Board of Trustees of the University of Illinois, n.d. Web. 13 Apr. 2016.

Figure 1
Polymeric Gel Electrolyte Consisting of Network Polymer Using Tri-Functional Glycerol Ester for Li-Ion Batteries
Authors: Tanji Seiya , Yamabuki Kazuhiro , Fujii Kenta , Morita Masayuki , Yoshimoto Nobuko 
Published: February 2020

Development of a safer electrolyte has become a key issue for realizing larger sizes of lithium-ion batteries (LIBs) for energy storage and transportation uses. Flame-retardant additives and/or ionic liquids are considered to be effective components that form safer electrolyte solutions. However, those systems still have risks coming from electrolyte leakage due to their liquid states. Solidification of the electrolyte is one of the effective ways to improve the safety of the battery system. In order to ensure sufficient ionic conductivity, a number of polymeric gel electrolyte systems have so far been proposed. We have investigated in this paper a novel polymeric gel electrolyte based on a network polymer having tri-functional glycerol ester for lithium-ion batteries.
A triply branched monomer possessing a terminal olefin unit was newly synthesized from glycerol ethoxylate (M
n~1,000) and 10-undecenoly chloride (3 eq.) (Fig. 1 (a)). The electrolyte consisting of 1 M LiPF6/ethylene carbonate (EC)/dimethyl carbonate (DMC) (1:1 by vol.) was added to a mixture of trimethylolpropane tris(3-mercaptopropionate) (Fig.1 (b)) and the triply branched monomer with a smaller amount of benzophenone sensitizer (1:1:0.05 by molar ratio). The resulting mixed solution was applied to a glass plate, and was broaden. Finally, the monomer-coated glass plate was exposed to UV irradiation to get a gel film. A transparent polymeric gel electrolyte was obtained as a self-standing film. The ionic conductivity of the gel electrolyte was measure by an AC method and found to be 5.2, 3.4, and 2.8 mS cm-1 (at 297 K) for the films containing 10, 20, and 30 wt% of polymer matrix, respectively. The electrochemical stability toward anodic oxidation was investigated for the gel electrolyte by linear sweep voltammetry (LSV). The anodic oxidation current was observed as a current peak at 4.2 V. This was attributed to the oxidative decomposition of the thiol group in the polymer matrix1). Thus, the present polymeric gel electrolyte can be used in a potential range up to 4.2 V. The application to the graphite negative and lithium iron phosphate (LiFePO4) electrodes will be reported in the presentation.
Reference
1) M.-H. Ryou, et al., Electrochim. Acta, 60, 23 (2012).

Figure 1
Chemically Anchored Liquid-PEO Based Block Copolymer Electrolytes for Solid-State Lithium-Ion Batteries
Authors: Gohy Jean Francois 
Published: February 2020

Solid-state electrolytes are being considered the keystone element for the development of safer all-solid-state lithium-ion batteries. While poly(ethylene oxide) (PEO) solid-state polymer electrolytes are known to support a lithium ions flux, satisfying conductivities are reached only above the melting point of the PEO crystallites rendering PEO unpractical. Herein, by means of block copolymer engineering, we design a mechanically clamped liquid-PEO electrolyte that combines the high ionic conductivity of a low molecular mass PEO while retaining the dimensional integrity of a solid material (1). Attractive ionic conductivities of about 0.01 mS/cm are attained at room temperature without compromising mechanical properties. The electrolyte shows a wide electrochemical stability window and help in building a stable interface with lithium metal. Competitive performances are attained when integrating the developed materials into operational/functional prototype batteries highlighting the provided potential.
Next, we discuss a three step synthesis procedure of self-doped solid block copolymer electrolyte, combining a single-ion poly(lithium methacrylate-co-oligoethylene glycol methacrylate) ion conducting block (P(MALi-co-OEGMA)) and a structuring polystyrene block (PS) (2). The macromolecular design allows the formation of a self-standing film with excellent mechanical properties provided by the PS anchoring nanodomains while attaining attractive ionic conductivities of up to 0.02 mS/cm at room temperature. Moreover, the single-ion configuration based on polyanionic backbone affords high transference numbers, close to unity, and alleviates the power limitation encountered in salt-doped solid polymer electrolyte (SPE). The electrolyte exhibits a wide electrochemical stability window up to 4.5 V vs. Li+/Li and promote the formation of stable interfaces at the electrodes.
(1) J. Rolland, J. Brassinne, J.-P. Bourgeois, E. Poggi, A. Vlad and J.-F. Gohy, J. Mater. Chem. A, 2014, 2, 11839–11846
(2) J. Rolland, E. Poggi, A. Vlad, J.-F. Gohy, Polymer
2015, 68, 344-352
Functional Design of Nitrile-Based Electrolyte Components
Authors: Grünebaum Mariano , Pelz Alexander , Rad Babak R. , Buchheit Annika , Krause Daniel , Pohl Benjamin , Winter Martin , Wiemhöfer Hans-Dieter 
Published: February 2020

Introduction

One of the crucial points for next generation lithium batteries is the development of high performance electrolyte components (e.g. electrolyte solvents, conducting salts and additives) to replace current LiPF6-based liquid systems. Novel electrolytes should guarantee high thermal and electrochemical stability, high ionic conductivity, long term stability of anode and cathode interfaces as well as they should lead to stable SEI films.[1-2]
On the other hand, electrolyte components should be nonflammable, nontoxic and environmentally friendly. This work is focused on applying basic chemical principles like inductive effects, sterical hindrance, increasing electronegativity and modification with fluoride splitting groups to model new nitrile-based electrolyte components (cf. Fig. 1).[3-4] The physicochemical properties of these new electrolyte components were investigated and different modification steps were compared.

Results and Discussion

Increasing the +I
effect, induced by electron donating substituents and the sterical hindrance of the nitrile-based electrolyte solvents led to highly cathodic stable nitrile-siloxane-solvents which are as well stable against metallic lithium in comparison to simple nitrile-based solvents like acetonitrile.[5] Additionally, they exhibit low vapor pressures and are in general nonflammable.

The here mentioned nitrile-based conducting salts show high anodic stabilities ranging from 4.5-5.6 V vs. Li/Li+ and in the cathodic region, they are stable down to the lithium metal stripping/plating process. In comparison to commonly used LiPF6, the lithium salts show very high thermal stabilities starting from 300 °C and raises to 500 °C with growing sterical hindrance.

Furthermore, BF3-modification of additive components led to stable passivation layers on aluminum current collectors and therefore to a better suppression of Al-dissolution, even in the presence of LiTFSI in carbonate type solvents. To sum it up, investigation and application of basic concepts on nitrile-based electrolyte components offer a simple tool for an easy tailoring.

References

[1] M. Winter, R.J. Brodd, Chemical Reviews, 104 (2004) 4245-4270.

[1] K. Xu, Chemical Reviews, 104 (2004) 4303-4418.

[3] M. Grünebaum, M.M. Hiller, S. Jankowsky, S. Jeschke, B. Pohl, T. Schürmann, P. Vettikuzha, A.-C. Gentschev, R. Stolina, R. Müller, H.-D. Wiemhöfer, Progress in Solid State Chemistry, 42 (2014) 85-105.

[4] J. Clayden, N. Greeves, S. Warren, P. Wothers, Organic Chemistry, Oxford University Press, United States, 2001.

[5] B. Pohl, M.M. Hiller, S.M. Seidel, M. Grünebaum, H.-D. Wiemhöfer, Journal of Power Sources, 274 (2015) 629-635.

Acknowledgements:
The author acknowledge the support of the Helmholtz-Institute Münster (HI MS) IEK-12 of Forschungszentrum Jülich.

Figure 1