bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting the Role of Interfacial Reactivity on SEI Layer Evolution Using Multimodal Analysis
Authors: Murugesan Vijayakumar , Prabhakaran Venkateshkumar , Mueller Karl T , Shutthanandan Vaithiyalingam , Swadipta Roy
Published: February 2020

Compositional and structural heterogeneity of solid-electrolyte interphase (SEI) layer arising from multitude of interfacial constituents and external stimuli is a major challenge in analyzing electrochemical interfaces. For example, the anode surface is typically filled with native oxide, hydroxide and carbonate layers with varying composition and thickness due to its high reactivity with environment. As the multitude of solvates (i.e. ionic solvation structures) from electrolyte interact with chemically inhomogeneous anode surface, the heterogeneity in SEI layer is inevitable. The challenge is to delineate each electrolyte constituent interactions with specific anode surface chemistry under realistic electrochemical conditions. Our team recently developed a unique ion soft-landing capability that can isolate ions (either solvated or bare) from liquid electrolyte based on their charge-to-mass ratio and selectively soft-land these ions (with kinetic energies of 1-100 eV) on metal electrode with tunable surface chemistry. This unique capability is equipped with in situ vibrational and X-ray photoelectron spectroscopy measurements, providing an unprecedented ability to isolate and analyze electrode-electrolyte interactions. We isolated Mg2+ ions with variant solvate structure and composition (e.g. varying number of counter anions as part of primary solvation sheath) and soft-landed on Mg metal electrodes with selected surface chemistry. The spectroscopic signatures of transient and decomposed products were analyzed in combination with first principle based calculations. This presentation will discuss the reaction pathways and products of interfacial reaction between selective Mg2+ based electrolyte components and Mg metal electrodes under variable temperature conditions.
Discharging-Charging Li Symmetric Batteries at High Current Densities
Authors: Wang Fangzhou , Li Xianglin
Published: February 2020

The electric vehicle (EV) has been drawing more attention and more widely used in recent years. However, the current Li-ion batteries cannot fully satisfy the EVs since the energy density is limited by the intercalation chemistry. The Li−O2 battery is one of the candidates that are promising to power EVs due to its high energy density. Even numerous efforts have been made to develop Li−O2 batteries, the low rate capability is a major obstacle that prevents the realization of this battery. In this study, we prove the feasibility of discharging-charging Li−O2 batteries using a Li symmetric battery design at high current densities (1.0, 5.0, and 10.0 mA/cm2). The Li chips are inserted in both the anode and cathode, respectively. Results show that the over-potentials caused by the Li chip during both the charging and discharging processes are less than 1.0 V. Besides, cycling tests of Li symmetric batteries are performed at 10 mA/cm2 with a cut-off capacity of 12.7 mAh. Therefore, the O2 diffusion or reaction rate in the cathodic electrode has been demonstrated to limit the capability of discharging and charging Li−O2 batteries at high current. It is urgent to enhance the O2 diffusion and reaction rates to increase the rate capability of Li−O2 batteries, which can benefit the realization of this technology. In our future work, we will pay more attention to promote O2 diffusion in the cathodic electrode by optimizing the porous structure of the electrode for Li−O2 batteries.
Fast-Charging All-Solid-State 3D Li-Ion Battery with Ultra-Thin Lipon and High-Capacity Electrodes Using Large-Area Atmospheric-Pressure Spatial ALD
Authors: Ameen Mahmoud , Poplawski Mateusz , Haverkate Lucas , Grob Frank , Anothumakkool Bihag , Hermes Dorothee , Khandan del Sepideh , Roozeboom Fred , Unnikrishnan Sandeep
Published: February 2020

The key challenges in next-generation all-solid-state Li-ion battery technology are related to the energy and power densities required, fast charging constraints, battery lifetime, while keeping the cost low by high-volume manufacturing. Currently, EVs are based on Li-ion batteries that often utilize highly flammable and toxic components such as liquid organic electrolyte, thus imposing a potential threat in case of failure. There is high pressure on developing batteries that are safer, smaller, and cheaper.

Here, we report on innovative materials and architectural approaches that have the potential to disrupt current Li-ion battery technology, especially by combining high-capacity with high charging/discharging rates. We aimed at improving 3D battery performance by using large area atmospheric pressure spatial atomic layer deposition (sALD) for further tuning the electrode and electrolyte layers at the nanometer-scale. Apart from enabling high charge/discharge rates, 3D electrode architectures pave the way for the use of high-capacity materials without long-term cycling challenges. We will show the potential of the intrinsically safe 3D all-solid-state batteries that can be extended to energy densities required for automotive (850 Wh/l and 375 Wh/kg at cell level).

However, novel architectures demand newer processing techniques, especially for conformal layer stacks over 3D structures. In this regard, we will present the results on high-rate 3D Li-ion battery electrodes coated using our patented sALD technology, which enables charging times below 10 minutes. Next, we will discuss the first-ever sALD-based LiPON electrolyte material, deposited at least 10x faster than the current technologies using conventional ALD systems, and exhibiting high Li-ion conductivity > 10-7 S/cm and very low electronic conductivity (< 10-12 S/cm). The LiPON layers are pinhole-free and demonstrated to be cycled without shorts. Such electrolytes are also relevant for the development of protection layers in wet electrolyte-based lithium ion batteries, as well as for enabling thin-film planar and 3D solid-state batteries with ultrathin electrolyte layers (few 10’s of nanometers). Highlighted during the presentation will also be the attribute of the sALD technique to produce conformal and upscalable coatings that can be applied in roll-to-roll processing using metal foils to further enable the innovative and cost-effective 3D battery layers.
Interphase Morphology between a Solid-State Electrolyte and Lithium Controls Cell Failure
Authors: Lewis John A , Cortes Francisco Javier Quintero , Tippens Jared , Boebinger Matthew G , Marchese Thomas S , Kondekar Neha , McDowell Matthew T
Published: February 2020

Solid-state batteries could enable improved energy density and enhanced safety compared to Li-ion batteries. The interfaces between many solid-state electrolytes (SSEs) and lithium metal are (electro)chemically unstable, however, and we lack a detailed understanding of how interfacial transformations relate to electrochemical degradation during cycling. Here, we characterize the (electro)chemical reaction processes that occur at the interface between Li1.4Al0.4Ge1.6(PO4)3 (LAGP) and lithium using in-situ transmission electron microscopy and ex-situ techniques, and we show that the growth of a new phase at the interface is intrinsically linked to chemo-mechanical degradation of the cell. Lithium insertion into LAGP at the interface drives the transformation to form an amorphous phase with expanded volume. In symmetric Li/LAGP/Li cells, the evolution of mechanical stress due to this transformation ultimately causes fracture of the SSE and an associated impedance increase. The morphology of the transformed interphase layer is highly dependent on the applied current density, and the interphase morphology significantly influences mechanical stability. Unlike many other SSEs (such as garnets), cell failure is not dictated by short circuiting. Instead, failure in LAGP is governed by the major increase in impedance as cracks are formed and continue to grow. This work shows that the nature of the reaction at the SSE/Li interface plays a crucial role in determining chemo-mechanical degradation mechanisms, with implications for understanding degradation in the whole class of SSE materials with unstable interfaces.
Computation-Guided Exploration for New-Chemistry Solid Electrolyte with Fast Ion Conduction and Good Electrochemical Stability
Authors: Mo Yifei
Published: February 2020

A key challenge in enabling all-solid-state Li-ion batteries is the development of solid electrolyte materials with high Li ionic conductivity and good electrochemical stability.Current research efforts on solid-state Li-ion conductors focus mostly on oxides and sulfides. Unfortunately, oxide and sulfide chemistries have an undesirable trade-off between ionic conductivity and stability. New solid-state chemistries that can exhibit a low activation energy, good stability, and other desirable properties are a promising research direction for new solid electrolytes in solid-state batteries.

Using ab initio computation, we systematically explored new anion chemistries beyond oxides and sulfides, such as nitrides and halides. Our computation found nitride anion chemistry exhibits unique stability against Li metal, which is either thermodynamically intrinsic or a result of stable passivation. Many nitrides materials can serve as promising lithium metal protection materials to achieve long-term stability.

In addition, our first principles computation study confirmed that chlorides and bromides exhibit fast Li-ion conduction, wide electrochemical stability, and good cathode interface compatibility. We found Cl and Br anion chemistries can achieve fast Li-ion conduction in a variety of anion sublattices, and do not require the rare bcc anion lattice as in current fast ion-conducting sulfides or the concerted migration mechanism in current fast-conducting oxides. Further, we found chlorides and bromides generally exhibit wide electrochemical windows, poor electronic conductivity, and good cathode interface compatibility, and thus hold desirable conducting and stability properties for SE applications.

Our presentation highlight nitrides, chlorides and bromides as highly promising alternative chemistries for solid electrolytes in solid-state batteries.

References:

Shuo Wang, Qiang Bai, Adelaide M. Nolan, Yunsheng Liu, Sheng Gong, Qiang Sun, and Yifei Mo, “Lithium Chlorides and Bromides as Promising Solid-State Chemistries for Fast Ion Conductors with Good Electrochemical Stability”, Angewandte Chemie (online)

Adelaide Nolan, Yizhou Zhu, Xingfeng He, Qiang Bai, Yifei Mo, “Computation-Accelerated Design of Materials and Interfaces for All-Solid-State Lithium-Ion Batteries”, Joule, 2, 2016-2046 (2018)

Yizhou Zhu, Xingfeng He, Yifei Mo, “Strategies Based on Nitride Materials Chemistry to Stabilize Li Metal Anode”, Advanced Science, 1600517 (2017)
Research on Solid Electrolytes for Lithium Batteries
Authors: Wang Chang-An
Published: February 2020

Solid electrolytes are the key materials to solve the safety problem of lithium metal batteries and all-solid-state lithium batteries. They can reduce the side reaction and prevent lithium dendritic breaking through electrolytes, and therefore, improve the cycling stability and safety of lithium metal batteries. This presentation briefly shows the research progress on Li-ion solid state electrolytes in my group in recent years, including NASICON-type LiZr2(PO4)3, Garnet-type Li7La3Zr2O12, perovskite-type Li3/8Sr7/16Hf1/4Ta3/4O3 ceramic electrolytes and organic-inorganic composite solid electrolytes. The modification on interfaces between electrolyte and electrodes were also studied.
New Fast Ion Conducting Glasses As Enablers for All Solid State Batteries
Authors: Martin Steve W , Hu Guantai , Kmiec Steven , Zhao Ran
Published: February 2020

Fast ion conducting glasses (FICGs) have long been considered as alternatives to flammable organic liquid electrolytes in Li batteries (LBs). However, to date, there has never been before the unique combination of the required electrochemical properties for use as a solid electrolyte (SE) in LBs with the equally important requirements of viscoelastic behavior to form them into thin films suitable for low resistance separators. Submicron thick RF sputtered films of the poorly conducting LiPON are well known for use in microbatteries. However, there is no report so far of 10s of micron thick "bulk" thin films that are suitable for use in high rate, long cycle life bulk LBs. In this first ever report of thick film FICGs, we will summarize our recent efforts to produce thick films of Li FICGs. We will show, through compositional optimization, that new Lithium based FICGs can achieve chemical and electrochemical stability, high Li ion conductivity, resistance to Li dendrite penetration, a wide > 4 V electrochemical stability window and at the same time the strong glass forming character, resistance to crystallization and stable viscoelastic behavior in the supercooled liquid state necessary so that they can be processed into long ribbons. In this talk we will summarize our efforts to make and characterize such ribbons and use and test them in symmetric and asymmetric cells.
Molecular-Level Organic-Inorganic Hybrid Solid State Electrolyte
Authors: Li Yejing , Liu Ping
Published: February 2020

All-solid-state batteries (ASSB) are of great interest due to their unique chemical/physical properties, such as non-flammability, no liquid leakage and gas generation, and a broad operating temperature range. Solid state electrolyte (SSE) can be divided into two categories: solid inorganic and polymer electrolytes. Inorganic electrolytes possess high ionic conductivities but are generally brittle and difficult to process. In contrast, polymer electrolytes are inherently flexible and easy to process but their ionic conductivities are generally low. Thus, extensive research has been devoted to combining the inorganic electrolyte and polymer electrolyte to achieve a balance in ionic conductivity and mechanical flexibility. The mechanical flexibility also enables hybrid solid electrolyte (HSE) to achieve an intimate contact/ improved interface with solid-state electrode. HSE has so far been fabricated by mechanical mixing of inorganic and polymeric materials which result in a heterogeneous mixture. It is often observed that interfacial issues between the components result in ionic conductivities far less than the values estimated from volume fractions and pure material performance.

Here we report the synthesis of a sulfide based HSE via an in-situ polymerization reaction. An inorganic Li-P-S electrolyte is used to trigger the polymerization of a sulfur containing precursor. As a result, the resultant composite achieved molecular bonding at the interface between the inorganic and the polymeric electrolytes. The interfacial structure was confirmed by the cryogenic-transmission electron microscopy and cryogenic-scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy. Owing to this molecular level interaction, the ionic conductivity of this HSE is as high as 2.91*10-5 S cm-1 at room temperature, which is very close to the value expected from the volume fractions of the components. An ASSB fabricated with the HSE along with LiNi0.80Co0.15Al0.05O2 as the cathode and Li-In alloy as the anode demonstrated stable cycling shown in Figure 1. Our work shows that molecular engineering at the interface is a promising approach to fabricate flexible HSEs with high ionic conductivity for ASSBs.

Figure 1
Microstructure Ramifications on Electrodeposition for Solid-State Electrolytes
Authors: Verma Ankit , Mukherjee Partha P.
Published: February 2020

Safe Li-ion batteries with enhanced energy and power density rely on utilization of lithium metal anodes in conjunction with non-flammable solid electrolytes that inhibit dendritic growth through mechanical rigidity. The kinetics, transport, mechanics complexations are strongly dependent on the microstructure of the solid electrolyte. In particular, garnet type electrolytes exhibit crystalline structure consisting of grain, grain boundaries and voids while glassy sulfide type electrolytes exhibit an amorphous structure with voids; with prominent dependence of the transport properties (ionic conductivity) and mechanical properties (shear modulus, fracture toughness) on the structural arrangement. The Li metal-solid electrolyte interface also shows a wide degree of stochasticity due to the imperfect solid-solid contact delineating the importance of surface roughness effects on kinetics and interlayer design to promote surface uniformity. In this work, we investigate these coupled interactions and delineate electrodeposition stability for aforementioned class of inorganic solid electrolytes cognizant of microstructural considerations.
Construction of Porphyrin-Sensitized Solar Cells Containing Toray™/TGP-H-060 Carbon - Based Cathodes
Authors: Manríquez Juan , Barroso-Martínez Jaxiry Shamara , Ortega-Díaz David , Bustos Erika , Gutiérrez-Granados Silvia
Published: February 2020

In this work, we present the construction and photovoltaic response of porphyrin-sensitized solar cells containing TorayTM/TGP-H-060 carbon – modified indium-doped tin oxide (ITO) cathodes (ITO/C), as a viable alternative for substituting platinum oxides – modified ITO cathodes (ITO/PtOx), which are traditionally employed for designing dye-sensitized solar cells. In this case, a binary mixture (75:25) of propylene carbonate (PC) : 3-methoxypropionitrile (MPN), containing 0.015M I2 plus 0.285M LiI was employed as electrolyte for filling the photo-cells.

On one hand, our experimental results demonstrated that both cathodic systems, ITO/C and ITO/PtOx, had a very comparable electron transfer kinetics when studied the cathodic semi-reaction I3
- + 2e­
- --> 3I- at these electrode surfaces.

Table 1. Electron transfer constants (k°) and cathodic transfer coefficients (∝c) obtained for the semi-reaction I3
- + 2e­
- --> 3I- at ITO/C and ITO/PtOx cathodes. Electrolyte: 0.015M I2 plus 0.285M LiI contained in a binary mixture 75:25 of PC:MPN at 25°C. A polycrystalline Pt cathode was also employed for comparison purposes.

cathode

Electron transfer kinetic parameters

k°/10-4 (cm/s) and ∝

c

Pt
5.31
0.27

ITO/PtOx

3.35
0.26

ITO/C
2.70
0.23

On the other hand, a detailed revision of Table 2 reveals that the photovoltaic responses of porphyrin-sensitized solar cells containing ITO/C and ITO/PtOx cathodes were comparable under simulated solar light (AM1.5, 100mW/cm2). These interestingly results confirmed that TorayTM/TGP-H-060 carbon – modified ITO cathodes are promising to substitute those PtOx – modified ITO cathodes typically employed for constructing dye-sensitized solar cells.

Table 2. Photovoltaic responses obtained for porphyrin-sensitized solar cells containing ITO/C and ITO/PtOx cathodes, where: Eoc, jsc, ff and ξ are open-circuit potential, short-circuit photocurrent, fill-factor and global conversion efficiency, respectively, under simulated solar light (AM1.5, 100mW/cm2).

cathode

Eoc

(V)

jsc (m
A/cm2)

ff

ξ(%)

ITO/PtOx

-0.30
1.23
0.39
0.17

ITO/C
-0.35
1.18
0.40
0.19

References

U.López-García, O.A.Castellanos, L.A.Godínez, J.Manríquez, “Electrophoretically-Assisted Deposition of Mesoporphyrin IX on Nanoparticulate TiO2 Films for Constructing Efficient Dye-Sensitized Solar Cells”, Journal of The Electrochemical Society, 158 (2011) F100-F105.
Conformal Dielectric Thin Film By Electrodeposition in 3D Porous Carbon Fiber Sheets
Authors: Li Wenyue , Fan Zhaoyang
Published: February 2020

Three-dimensional porous carbon materials with conformal dielectric coatings have great potential to be used for 3D dielectric capacitors or for 3D interpenetrated micro-batteries if the dielectric film is also an ionic conductor. Exploring methods to build a continuous and conformal insulated thin film on porous carbon materials has been highly desired. However, due to their complicated structures, achieving this well-defined insulating layer is very challenging and only few studies have reported but mostly on planar carbon materials. In our study, carbon film composed of carbon nanofibers which was synthesized via electrospinning method were used as substrate to conduct the dielectric layer coating via electrodeposition techniques. Using an ionic liquid (1-Butyl-1methylpyrrolidinium dicyanamide) as the electrolyte and the monomer source, conformal dielectric thin film on the porous carbon sheet was produced which was proved by the extension of their working voltage window from below 3 to 10 V in an ionic liquid electrolyte. In addition, by adjusting the parameters of the electrodeposition, the properties of the dielectric layer could be tuned, which is reflected on the change of their electrochemical performances. The properties of this dielectric thin layer will be presented.
Complex Capacitance Analysis on Electrochemical Properties of Passive Film Formed on Rebar in Concrete
Authors: Inohira Kanaho , Hoshi Yoshinao , Shitanda Isao , Itagaki Masayuki
Published: February 2020

Reinforced concrete structures have been widely used for the social infrastructures because the rebar embedded in concrete shows high corrosion resistance due to the formation of passive film formed on the rebar. The monitoring of the conditions of the passive film formed on the rebar is important to ensure the proper maintenance and management of reinforced concrete structures. An electrochemical impedance spectroscopy (EIS) is a useful method to evaluate the corrosion state of reinforced concrete nondestructively1, 2). In the present study, the stability of passive film formed on the rebar was evaluated in the concrete simulated environment by the EIS.

A saturated calcium hydroxide solution was used to simulate the environment in concrete. The chloride ion concentration was adjusted to 3.8 mmol dm-3 and 16 mmol dm-3 by adding sodium chloride to a saturated aqueous solution of calcium hydroxide. The electrochemical impedance measurement was carried out by a three electrode system. A rod electrode made of cylindrical carbon steel (SR345) that has the same composition as rebar SD345, as is often used in actual structures, was adopted as a working electrode. A saturated KCl silver / silver chloride electrode and a platinum wire were used as a reference electrode and a counter electrode respectively. The electrochemical impedance was measured every 12 hours during immersion. The 3D impedance was measured in order to investigate the time-dependent change of the thickness of the passive film. An electrochemical measurement system (HZ-7000, Hokuto Denko Corporation) was used as the measurement device. The measurement frequency range was 10 kHz to 10 mHz with 5 points per logarithmic sweep.

By plotting the admittance and capacitance calculated from the impedance of carbon steel on the complex plane, the resistance and capacitance of the passive film formed on the carbon steel were evaluated. The changes of thickness of passive film formed on the carbon steel with time were discussed.

References

1) J. L. Dawson et al., Proceedings of NACE Corrosion / 78, Paper No. 125 (1978).

2) Yoshinao Hoshi et al., Electrochemistry, 87, 78-83, (2019)

3) Masayuki Itagaki et al., Electrochemistry, 75, 649-655, (2007).
(Invited) Progress on Turning Electrochemical Acoustic Signal Interrogation from a Diagnostic to a Characterization Tool
Authors: Steingart Daniel A.
Published: February 2020

All batteries, lithium ion and otherwise, are a challenge to fully characterize because of the variety of length scales in play and media involved (metals, ceramics, polymers, liquid solvents, etc). Recently electrochemical-acoustic signal interrogation (EASI) methods have been studied as a bridging method for characterization and diagnostics. The performance of a battery is strongly coupled to its geometric regularity (or irregularity). The fundamental requirement for mass conversation within a closed battery coupled with the lack of requirement for elastic conservations indicate that sound speed can be used in multiple ways to probe changes in the electrochemical cell. Akin to the fingerprints of electrochemical impedance spectroscopy (EIS), this method provides direct information on structure and indirect information on dynamics where EIS provides direct information on dynamics and indirect information on structure. In this presentation we present the learnings in electrochemical-acoustic analysis on full cell behavior including lithium deposition (wanted and otherwise), state of charge, state of health, state of power, and gas evolution. Our current understanding of detection limits and potential new applications will also be discussed.
(Invited) Implementation of Three-Dimensional Solid State Battery
Authors: Heo Jin S. , Park Hwi-Yeol , Jeong Huisu , Kim Kyounghwan , Lim Sungjin , Shon Jeong-Kuk , Yang Ho-Jung
Published: February 2020

While increasing the multifunction of wearable devices such as smart watch, earphone, and glasses, the run-time of battery is getting more important to be a competitive product in the wearable market. In order to get more reliable and longer lasting battery, the concepts of 3D battery architecture have been suggested to improve energy density [1].

Several 3D microbattery architectures have been proposed to maximize the areal energy density and rate discharge capability by maintaining short ion-transport distances between cathode and anode [2]. However, the implementation of high areal capacity 3D electrode is difficult to fabricate due to the limitation of manufacturing processing [3]. Moreover, conventional fabrication technology of the thin film electrolyte cannot make good step coverage of the 3D conformal electrolyte.

In this research, we propose technical approaches to fabricate a high energy density 3D battery structure with good step coverage of the 3D conformal electrolyte. First, we developed a high aspect ratio (=h/w, where h is height and w is width of cathode) 3D cathode which consists of only LiCoO2 with high electrode density without any binder and conductive additives. And then, two kinds of different solid electrolyte layers, LLZO and LiPON, were applied to the 3D conformal coating on the 3D cathode by sol-gel and CVD processing. The process of sol gel and CVD efficiently improved step coverage of 3D conformal electrolyte. Subsequently, Li-metal was evaporated to make a bed for striping and plating as anode. Finally, the 3D solid state battery was evaluated and analyzed for the feasibility study of a next generation battery.

References

[1] Jeffrey W. Long et al, Chemical review, 104 (2004) 4463-4492

[2] Stefania Ferrari et al, J. Power Sources, 286 (2015) 25-46

[3] Matthew Roberts et al, J. Mater. Chem, 21 (2011) 9876-90
(Invited) Construction of Flexible Interfacial Layer for Solid-State Li Batteries
Authors: Yang Yong
Published: February 2020

There is a growing interest in all-solid-state lithium batteries(ASLBs) for their safety and high energy density. However, the power density for ASLBs is still far away from satisfactory on the account of high interfacial resistance at electrode / solid electrolyte interface.

For example, Garnet-type solid-state electrolytes (SSEs) are considered as a good choice for solid-state batteries, yet the interfacial issues with metallic Li limit their applications. In my group, we propose an ultra-simple and effective strategy to enhance the interfacial connection between garnet SSEs and Li metal just by drawing a graphite-based soft interface with a pencil[1]. Both experimental analysis and theoretical calculations confirm that the reaction between graphite-based interfacial layer and metallic lithium forms a lithiated connection interface with good lithium-ionic and electronic conductivity. Compared to the reported interfacial materials, the graphite material provides a soft interface with better ductility and compressibility. With the improvement by this soft interface, the impedance of symmetric Li cells significantly decreases from 1350 to 105Ωcm2 and the cell can cycle for over 1000hoursat a current density of 300 μA/cm2 at room temperature. Moreover, a solid-state battery with Li-metal anode, ternary cathode NCM523 and graphite-based interface modified garnet SSEs is fabricated and displays excellent rate capability and long cycling performance.

In addition, LGPS-type materials show extremely high Li+ conductivity. But when in contact to Li metal, they can be reduced to produce Li2S, Li3P and Li-M alloy and form a mixed ionic and electronic conducting layer at the interface, which hinders the application of Li metal in such solid electrolyte system. We report on a simple approach for the modification of the interface between Li and Li10SnP2S12 sulfide solid electrolyte by utilizing ionic liquid[2]. Our study shows that the addition of 1.5M LiTFSI/Pyr13TFSI ionic liquid can not only promote intimate contact but can in-situ form a stable SEI layer at the interface between Li and solid electrolyte as well. A stable SEI layer instead of mixed conducting layer can prevent sulfide solid electrolyte from further decomposition and improve the cycle performance of batteries.

References:

1) Y.J. Shao, H.C.Wang, et al ; ACS Energy Lett.; 2018, 3, 1212-1218

2) B.Z. Zheng; J.P.Zhu, et al; ACS Applied Mater. & Interfaces; 2018, 10, 25473-25482
(Keynote) Where are Batteries Going?
Authors: Crabtree George
Published: February 2020

Lithium-ion batteries are expanding well beyond their initial market in personal electronics, to encompass electric vehicles, the electricity grid and some forms of electric flight. These new applications require new standards for higher performance, lower cost and greater safety. Batteries have several promising options to meet these challenges, including incremental improvements to the basic lithium-ion platform, substantial modifications of the lithium-ion platform, (often called advanced lithium-ion) and entirely new concepts beyond the lithium-ion platform. The challenges, opportunities and applications of each option will be considered.

This work was supported as part of the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the US Department of Energy, Office of Science, Basic Energy Sciences.
(Keynote) Designing Lithium Metal Anodes: Host Materials and Solid Electrolyte Interphase
Authors: Cui Yi
Published: February 2020

Lithium metal anode is critical for new generation of high energy batteries. We identified that the two root causes of Li metal problems are high chemical reactivity and infinite relative volume change during Li metal plating and stripping. Nanoscale materials design represents a new powerful paradigm shift and offers new solutions to address these challenges. Here I will present our understanding and progress on: 1) Nanoscale design of host and interface for Li metal anodes; examples of host materials include graphene oxides, hollow carbon spheres, metal fluoride and oxide. We also developed robust interfacial layer materials and synthesis process for BN, Li3N and LiF. 2) Demonstration of cryogenic electron microscopy applied to battery materials research, leading atomic scale resolution of Li metal dendrite and solid electrolyte interphase. We also established the correlation of the SEI structure with battery performance.
(Keynote) Taking a Closer Look at SEI Chemistry
Authors: Xu Kang C.
Published: February 2020

Interphases enables the electrodes to operate at potentials beyond what thermodynamic stability limits of non-aqueous electrolytes would allow. The most prominent example of interphases is perhaps solid-electrolyte-interphase (SEI) on graphitic anodes in Li-ion batteries, which ensures the reversibility of Li-ion intercalation chemistries. In typical electrolytes, chemical building blocks of SEI mainly come from solvents decomposition products, and, although we often acknowledge that many aspects of SEI remains unknown, we thought we at least have establish the following foundation beyond doubt: (1) semi-carbonates from the single-electron reduction of carbonate solvents constitutes the major portion of SEI; (2) the formation of SEI is irreversible; and (3) SEI is ionic conductor and electron insulator. However, when taking a closer look at the “olde SEI” using a series of new techniques, we found some of those principles might need to be re-written.

In this work, I will summarize the newest understanding of this “least understood” component in Li-ion battery that were achieved in my own group and my collaborators.
(Invited) The Scale-up and Commercialization of a High Energy Density Na-Ion Battery Technology
Authors: Barker Jerry
Published: February 2020

Na-ion batteries represent an attractive alternative to their Li-ion counterparts [1,2]. Faradion Limited, a UK-based startup, has developed this battery technology to a point where its performance characteristics, such as specific energy, rate and cycle life, are competitive with commercial Li-ion cells. In addition, the company has built an extensive patent portfolio [3]. Prototype Na-ion cells are manufactured on existing, commercial Li-ion production lines using readily available equipment and proven battery designs. Cylindrical, prismatic and pouch cells are all under development [4].

In this presentation we will demonstrate the performance characteristics of prototype Na-ion cells constructed using a proprietary layered oxide cathode NaaNi(1-x-y-z)MnxMgyTizO2 and a hard carbon anode material [5]. In this configuration the cathode material delivers a reversible specific capacity of over 150 mAh/g and the cell generates an average discharge cell voltage of around 3.2 V. The cell cycles with low polarization and with excellent charge and energy (round-trip) efficiency.

To demonstrate the commercial viability of Na-ion batteries, Faradion has worked with its commercial partners to scale-up its Na-ion cell chemistry to the 40 Wh and 80 Wh pouch cell level. These prototype cells deliver a specific energy of around 140 Wh/kg under full depth-of-discharge conditions and have been incorporated successfully into E-Bike, E-Scooter (>750 Wh) and other demonstrator applications [6,7]. These developments will encourage rapid penetration into new market opportunities.

Further performance, cost and safety characteristics of the Faradion Na-ion cells and batteries will be presented. Detailed 3-electrode cell performance data will also be discussed.

References:

J. Barker, M.Y. Saidi and J. Swoyer, Electrochem. Solid-State Chem. 6, A1, 2003.

V. Palomares, P. Serras, I. Villaluenga, K. B. Hueso, J. Carretero-Gonzalez and T. Rojo, Energy Environ. Sci. 5, 5884, 2012

For example, US Patents US#9761863, US#9608269, US#9917307, US#10050271.

A. Bauer, J. Song, S. Vail, W. Pan, J. Barker and Y. Lu, Adv. Energy Materials, 2018, 1702869; doi.org/10.1002/aenm.201702869

J. Barker and R.J. Heap, US Patent#9474035. Doped Nickelate Compounds, Filed November 2013

J. Barker and C. J. Wright. Presentation at the Advanced Automotive and Stationary/Industrial Battery Conference, AABC, Detroit, Michigan, USA, June 2015.

Chemical & Engineering News, July 20, 2015, Vol. 93, Issue 29, pp 18-19.
(Invited) Improvements in High Energy Density Silver-Zinc Button Cells for Wearable Devices
Authors: Wei Xia , Ortega Jeffrey Vincent
Published: February 2020

The silver (Ag)-zinc (Zn) system has the highest theoretical specific (Wh/kg) and volumetric energy density (Wh/L) amongst all rechargeable batteries with the added benefit of safety and non-flammability compared to lithium-ion or lithium metal batteries, which makes it a good and ideal candidate for portable applications like hearing-aids. However, historically, the Ag-Zn battery has suffered from poor rechargeability and low energy utilization. At ZPower, we have tailored the chemistry and engineered a new Ag-Zn battery system, which is highly energy dense and rechargeable, thus making it possible to use it portable applications and giving more power to the consumer to allow them to contribute to a greener future.

As aforementioned, enhancing the capacity of the active materials is paramount for high energy density, which we achieved by developing proprietary additives and methods. For the cathode, silver oxide (AgO) was used in our system. We developed novel proprietary conductive coatings for AgO, which allowed high capacity utilization and retention for many cycles. We conducted gassing tests, where we found the coatings considerably reduced oxygen generation. The role of these coatings was further studied through charge algorithm cycling, where we found that it reduced AgO cathode’s impedance compared to the control tests and maintained its active surface area. More importantly, we found that the morphology of the proprietary conductive coatings played a crucial role in efficiently utilizing the AgO cathode’s capacity.

For the anode, Zn was used, where it has a theoretical specific capacity of 820 mAh/g; however, Zn has a long history of poor rechargeability due to problems like shape change (zinc redistribution), dendrite formation and passivation. In the past, previous researchers tried altering the Zn formulation to increase utilization; however, these attempts were not fruitful. We have engineered a new Zn anode that can access 94% of its theoretical capacity in a single primary discharge and 56% of its theoretical capacity rechargeably for over 300 cycles. We achieved this breakthrough by developing proprietary additives and methods that localize the Zn to the current collector and prevent dendrite formation. We will comment on the anode performance further in the talk.

Finally, we will present impedance models and data of the ZPower Ag-Zn system measured with respect to state of charge, storage time and temperature, which is vital from a manufacturing standpoint to understand cell properties and make future cell and electrode improvements. We will comment on our future work of identifying impedance contribution from the cathode and anode components of the battery and using this data as a guideline for improving electrode composition and cell performance.
Electrolyte Design for Self-Forming and Self-Healing SEI Layer for Li Metal Anodes
Authors: Pande Vikram , Viswanathan Venkatasubramanian
Published: February 2020

The driving range and cost of electric vehicles is severely limited by the energy density of the state of art Li-ion batteries. The energy density of Li-ion batteries can be improved by replacing graphite anodes with lithium metal anode. The US Department of Energy targets for lithium metal batteries are cost < 100 $/kWh, gravimetric energy density > 500 Wh/kg, volumetric density > 800 Wh/L and have a charging time of 15 min. Lithium metal anodes suffer from dendrite/mossy formation and low cycling efficiency. It has been shown that forming stable SEI layers on top of lithium metal anodes can stop dendrite formation.[i],[ii] Electrolyte components play a crucial role in formation of stable SEI and also the SEI morphology, as the SEI components primarily comprise of decomposition products of the solvent, the salt and the additives in the electrolyte.

In this work, we will discuss a new approach of forming a stable SEI layer with sufficient ionic conductivity and mechanical strength to suppress dendrites . The battery under cycling conditions will unavoidably form cracks in the SEI layer. Our approach is to provide a persistent source for self-healing of these cracks formed in the self-formed SEI during battery cycling. This is achieved by choosing appropriate solvents, salt anions and additives in the battery, which will form the same SEI layer during a forming step and during cycling of the battery. Using the appropriate solvent, salt and additives in the desired proportion leads to a spontaneously formed SEI layer comprised of specific components such as LiF, LiOH, Li2O, Li2CO3, Li2SO3, Li2S. The design principles associated with the selection of the electrolyte additives and salt components will be discussed. The effectiveness of the different SEI components will also be compared. We will quantify the amount of electrolyte components required for self-healing during entire cycle life. An important consideration is that the dissolved species in the electrolyte should also be stable to against high voltage Li-ion battery cathodes. Thus the high voltage stability of the electrolytes will also be shown. We will also explore the ion conduction pathways in SEI through the interfaces formed by the different SEI components. We will also discuss formation of stable SEI in the context of thin lithium foils (< 20 mm) and anode free batteries. Lastly the effect of the current collector in the context of anode free batteries will be discussed.

[i] Xin-Bing Cheng, Rui Zhang, Chen-Zi Zhao, and Qiang Zhang. Toward safe lithium metal anode in rechargeable batteries: a review. Chemical reviews, 117(15):10403–10473, 2017.

[ii] Dingchang Lin, Yayuan Liu, and Yi Cui. Reviving the lithium metal anode for high-energy batteries. Nature nanotechnology, 12(3):194, 2017.
Micro Vs. Nano: Impact of Particle Size on the Processing of Si Anode Slurries
Authors: Mindemark Jonas , Andersson Rassmus
Published: February 2020

In the quest for ever greater storage capacity to satisfy the increasing demand for high-energy-density storage in electric vehicles and large-scale grid storage, anodes comprising Si have the promise of significantly increasing the energy density of Li-ion batteries [1]. Either as a stand-alone active material or as a minor component in a more traditional graphite matrix, Si can through alloying incorporate far more Li than can be intercalated in graphite [1]. This, however, comes at significant volume expansion of the Si particles, resulting in cracking and disintegrating during repeated cycling [2]. This can be counteracted by using nm-sized Si particles which minimizes the impact of severe volume changes during cycling [2].

We have been studying the processing of environmentally benign water-based slurries for Si-containing anodes and note that the Si particle size not only affects the cycling performance, but also significantly affect the processing characteristics. Notably, the rheological properties, i.e., the shear stress and apparent viscosity at the shear rate of electrode coating and the viscoelastic properties, are all determined by the Si particles – even when these are only present as a minor component in a graphite matrix. Whereas µm-sized Si particles result in low-viscosity slurries that are characterized by liquid-like behavior, the slurries containing nm-sized Si particles show both higher viscosity and notable viscoelasticity. These differences are most pronounced at low shear rates, which in the context of electrode processing will affect how the slurry will either flow under its own weight or retain its overall geometry between application and drying. These vastly differing properties appear to be related to the surface area of the Si particles within the slurry, where the polar surface groups of the native oxide on the particles interact strongly with the surrounding water, leading to the observed differences in rheological behavior.

Thackeray MM, Wolverton C, Isaacs ED. Energy Environ. Sci. 2012; 5: 7854

Casimir A, Zhang H, Ogoke O, et al. Nano Energy 2016; 27: 359–376
Hydrophilic-Modified Electrospun PBI Membranes for Secondary Battery Separator
Authors: Nam Sang Yong , Jung Ji Hye
Published: February 2020

The main roles of the secondary battery separator are the active movement of lithium-ion through pores, prevention of physical contact between anode and cathode, and prevention of electrical isolation. The currently used separator is PE film. PE films have the advantage of being cheap, but they are weak at high temperatures. By the way, Polybenzimidazole is well known for its superior heat resistance and mechanical properties. Due to an excellent various property, PBI has been used in a lot of fields such as gas separation, OSN and secondary battery membrane. This work is focused on fabrication of Polybenzimidazole(PBI) using Electrospinning and modified the PBI membrane as hydrophilic using 4-(chloromethyl) benzoic acid(CMBA) and Sulfuric acid. The membrane was crosslinked by α,α’-Dibromo-p-xylene. To observe morphology, scanning electron microscope(SEM) was used and to check the hydrophilicity, contact angle test was performed. In case of separator properties, cycling test of those membranes was conducted.
New Insights into the Passivation Behavior of Silicon Electrodes in Silicon-Air Batteries with Alkaline Electrolytes
Authors: Schalinski Richard , Griesche Benjamin , Schweizer Stefan L. , Wehrspohn Ralf B.
Published: February 2020

The chemical etching of silicon has been investigated thoroughly during the past 40 years to achieve a fast and controlled process for texturing surfaces. Nonetheless, still little is known about the electrochemical reaction of silicon with KOH for the use in batteries. The high theoretical capacity density of 3817 mAh cm-2 and potential of 2.09 V make the silicon-air system a promising candidate for energy storage. However, a crucial constraint to the use of an aqueous alkaline electrolyte, such as KOH, is related to the fact that the system discharges only once. Overpotentials reduce the practical potential to 1.4 V, and the competing chemical corrosion of the silicon leads to a strong self-discharge, resulting in a low conversion efficiency. The discharge ends with a sudden potential drop, due to the passivation of the silicon surface before the complete consumption of the electrode. We believe that understanding the mechanisms behind that potential drop and the processes that lead to it are essential to the further improvement of this silicon-air battery. Therefore, we studied cells with different KOH concentrations and with flat phosphor-doped silicon (100) wafers as the Si-electrodes. To investigate the potential drop and increase the conversion efficiency of silicon electrodes, we performed electrochemical measurements in a full cell setup. Galvanostatic discharge tests revealed that the ratio of electrochemical to chemical reaction is influenced by the KOH concentration when the battery is discharged till the passivation. While the highest etching rate for silicon in KOH solution reaches its maximum around 6 mol L-1 KOH, the electrochemical reaction seems to have a peak at 2 mol L-1 KOH in our experimental conditions. We compared the performance of cells with various concentrations of pre-dissolved silicon in KOH and we found a correlation between the silicon content in the electrolyte and the time before the potential drop occurred. The conductivity of the solution decreases with increasing silicon content, probably as a result of the presence of a network of silicate species, which might hinder the diffusion of the Si(OH)4 species. To prove this hypothesis, we tested different volumes of the electrolyte with the same cell parameters. The use of an excess of electrolyte solution enabled the complete consumption of the 500 μm Si-electrode in any KOH concentration used. During these experiments, the silicate species do not reach the critical concentration, and the reaction products can dissolve into the bulk electrolyte, not leading to the formation of a passivation layer.

Figure 1