bluuebunny/crossref_metadata_2025 huggingface dataset:
Ab-Initio Modeling of the Electrochemical Potential Effect in Facilitating Heterogeneous Reactions on Catalysts Surface
Authors: Hajar Yasmine M. , Michel Carine , Baranova Elena A. , Steinmann Stephan
Published: May 2020

Theoretical modeling of the effect of electrochemical potential on reaction rate will be presented. Using ab-initio Density Functional Theory (DFT), adsorption and dissociation energies are calculated at the atomistic level for the model ethylene oxidation reaction on a ruthenium oxide slab RuO2 (110). Using the surface charging method, known as grand-canonical DFT, the number of electrons is changed on the slab surface to mimic an electrochemical potential application and thus a change in the work function of the surface. Next, a fitted curve is found for the calculated adsorption energies as a function of the changed potential. A similar approach is used for the calculation of dissociation energies (using minimum energy pathway MEP method). The end models showed an electrochemical potential effect on the adsorption energy of reactants as well as on their dissociation energy. This type of modeling helps us understand on the atomistic level what occurs on the surface of a catalyst in a heterogeneous type of reaction under the effect of an electrochemical potential.
Metallization of High Density Polyurethane Surfaces
Authors: Aykac Busra , Karakaya Ishak , Erdogan Metehan , Oz Yahya
Published: May 2020

Electroplating onto polymeric materials is required for different purposes in various applications. Polyurethane (PU) is an electrically insulator material and durable at high temperatures. Furthermore, it has high thermal conductivity, low thermal expansion coefficient and is a high density foam. In this study, surface metallization of polyurethane foam, involving activation and sensitization processes, was studied to prepare the surface for subsequent electroplating process. The surface metallization was carried out by multi-step processes which included degreasing, etching, sensitization, activation and electroless nickel plating. Metallized surfaces were tested for electrochemical nickel plating at different current densities and surface morphology, roughness and physical properties of the coatings were characterized. The results showed that increasing current density adversely affects the surface morphology and surface sensitization and activation processes increased the surface conductivity of foam.
Highlighting the Use of Brush Plating for Plating on Titanium, Nickel Plating, and Metal Matrix Composite Materials
Authors: Thomas Joshua David , Milosevic-Popovich Danijela
Published: May 2020

Selective or brush plating is an application method for electrodeposition which can be used for coating an array of pure metals, alloys, and composite materials. The ‘brush’ in brush plating describes a porous, non-conductive, flexible material which wraps the anode to keep it separated from the part to be plated. The plating solution is applied by rubbing the anode, covered with the brush material and saturated by the plating solution, against the area to be plated. This is done in lieu of dipping the entire part in a large tank of plating solution. Brush plating has seen its most advantageous use in plating smaller areas of larger parts because the amount of masking used can be reduced, and smaller volumes of solution can be utilized compared to traditional tank plating methods. Brush plating is portable and repair plating can be performed in the field, sometimes without even disassembling equipment. Brush plating is currently used for numerous specialty applications in the fields of aerospace, oil and gas, marine environments, manufacturing, and many others.

The process of brush plating will be presented in terms common to all electroplating processes. The effects of facets particular to brush plating shall be clarified in terms of their contributions to the molecular level and to the properties of the resulting deposit. Applying solution by brushing it onto a part leads to different formulations of the plating solution compared to other plating methods. The application method (brushing) promotes fast solution replenishment at the electrode surface and dissipation of species generated by side reactions at the work surface. The type of brush material used on the anode will affect the type of surface finish or even the structure of the deposited material.

The presentation will include a summary of a brush plating process for depositing nickel pre-plate on titanium with strong adhesion, highlighting advancements made to the plating process for a classic sulfamate nickel plating solution formulation, and evaluating differences in solution composition focusing on particle loading.

M. Rubinstein, Electrochemical Metallizing, Vinmar Press, New York, NY (1987)

D. Vanek, Met. Finish., 108, 25-32 (2010)

Figure 1
(Invited) Enhancing Oxygen Stability in High-Nickel Cobalt-Free Layered Oxide Cathode Materials By Three-Dimensional Targeted Doping
Authors: Xin Huolin , Lin Feng , Persson Kristin A , Xu Wu , Kompella Christopher
Published: May 2020

The price of cobalt, a key element within lithium-ion batteries (LIB) for stability, has nearly tripled over the past few years due to increased demand from the cell phone industry, a current materials shortage, and speculation for a future global shortage. Given the increase in cost and the future outlook, lithium-ion battery (LIB) research focused on the reduction or the elimination of cobalt within a LIB is essential for reducing the cost and assuring the supply of lithium-ion batteries. This talk will report on the development a novel three-dimensional (3D) doping approach that is poised to resolve some longstanding challenges in fundamental doping effects on high-Ni Co-free battery materials as well as to reduce the cost and improve the safety, energy density, and lifetime of LIBs.
Functionally Graded Materials for Long-Cycle Lithium-Ion Batteries
Authors: Yang Yang
Published: May 2020

Transition metal (TM) dissolution and volume expansion of high-capacity TM-based materials are always the the Achilles Heel of lithium-ion batteries (LIBs), leading to poor safety and reliability of LIBs-powered devices and instruments. Even though some surface passivation materials and techniques have been employeed to address these issues, more parasitic effects occur at the heterogeneous coating-electrode interfaces, such as internal resistance, lattice strains, and capacitive internal electric field, which negatively affect LIBs performance. Hence, it is of vital importance but very challenging to develop an effective strategy for the TM-based electrode protection. In this work,we used functionally graded materials (FGM) as an ideal solution to developing novel electrodes for long-cycle LIBs. In such materials, a homologous passivation layer (HPL) with a similar elemental composition but different stoichiometry is rationally designed to passivate "conversion-type" cathodes by forming a structure/composition gradient in order to resolve these fundamental challenges and technical problems for the TM-based electrode surface passivation. The structure and composition reconstruction of HPL help to buffer the volume change and trap the dissolved transition metals. As a result, a significantly improved cyclability of LIBs is achieved, which opens a new avenue for the electrode stabilization.
Enhanced Capacity and Retention in Lithium Iron Orthosilicate Cathode Via Tuning Its Composition By Hydrothermal Synthesis
Authors: Zeng Yan , Zaghib Karim , Demopoulos George P.
Published: May 2020

During the past three decades, scientists have designed and tested a range of new materials for application in Li-ion batteries to meet the increasing energy storage demand. Still, the quest for delivering higher energy density while being safer and sustainable remains an ongoing challenge for Li-ion batteries. This work presents our recent efforts on improving an important cathode material, Li2FeSiO4 (LFS), in order to make use of its attractive properties in terms of sustainability and safety. We apply compositional engineering to tune the electronic and crystal structures of LFS and eventually its electrochemical performance. We take advantage of the versatility of hydrothermal synthesis and synthesize various cation-substituted and non-stoichiometric LFS in orthorhombic Pmn21 structure. Partially substituting Co for Fe is found to allow faster phase transformation from pristine Pmn21 to inverse Pmn21 with important positive ramifications in its cycling performance. More interesting, the insertion of Co alters the surface activities of LFS and induces the formation of cathode-electrolyte interphase (CEI) layers with lower resistance and better uniformity that protect the bulk particles from detrimental reactions with the electrolyte. Consequently, the participation of Co helps LFS to have improved capacity retention. To boost the capacity of LFS, we design Fe-rich LFS materials that deliver higher capacity within a reasonable voltage window. By combining DFT calculation with experimental testing, we find that Fe-rich composition LFS shows also promise in facilitating electronic and ionic transport.
Temperature Stability of Interfaces in Lithium-Sulfur Batteries with Nominally Stable Electrolytes
Authors: Ware Skyler , See Kimberly A
Published: May 2020

Li-S batteries are a promising alternative to conventional Li-ion batteries as Li-S batteries enable low-cost, lightweight, and high capacity cells. However, the polysulfide shuttle effect and Li reactivity with common organic solvents have limited commercialization of Li-S batteries. Highly concentrated electrolytes known as solvate electrolytes have been shown to limit polysulfide solubility in Li-S cells by reducing the ability of solvent molecules to solvate polysulfides through coordination to Li+.1 The challenges with using solvate electrolytes in electrochemical cells are associated with the high viscosity and low ionic conductivity of solvates. Addition of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) significantly decreases the solvate viscosity with slight improvement in ionic conductivity.1 TTE has been shown to suppress the polysulfide shuttle effect and is suggested to act as a nonsolvent for polysulfides.

Although bulk electrolyte speciation is unchanged when the solvate is exposed to Li metal,2 the reactivity of the solvate electrolyte with and without TTE with Li metal has not been studied in detail. To study the reactivity, we evaluate the behavior of Li-S cells and Li metal at various temperatures in the solvate electrolyte with and without TTE. Increasing the temperature of the solvate electrolyte affects the equilibrium between free and coordinated MeCN and results in increased electrolyte decomposition and anode passivation. We demonstrate here that reactivity between the solvate electrolyte and the Li anode significantly impacts the cyclability and capacity retention in Li-S cells. The results indicate that TTE is necessary to stabilize the electrode/electrolyte interface and mitigate Li reactivity. Introducing a protecting layer onto the Li anode enables moderate cyclability but does not protect against decomposition over time.

1. Energy Environ. Sci.
2014, 7, 2697.

2. J. Am. Chem. Soc.
2014, 136, 13, 5039.
(Invited) Electrolyte Chemistries of Mg Batteries
Authors: Liu T. Leo
Published: May 2020

Mg is earth abundant and low-cost (ca. 24 times cheaper than Li), and as an anode material, Mg is safe to use (vs. Li, Li-ion, or Na-ion batteries). Its high gravimetric capacity (2,333 Ah/kg) and high reduction potential (-2.37 V vs SHE) allow the assembly of high-energy density batteries. However, despite rapid research progress, the lack of high performance Mg2+ conductive electrolytes still present a primary technical hurdle for developing practical Mg batteries. The presentation will cover our research efforts in developing high performance Mg electrolytes for Mg rechargeable batteries. Specifically, we will present the synthesis and electrochemical performance of ternary Mg/MgCl2/AlCl3(MMAC) electrolytes and a novel Cl free perfluorinated pinacolatoborate Mg electrolyte (Mg-FPB). These MMAC and Mg-FPB electrolytes exhibited up to 100% Coulumbic efficiency, and < 200 mV overpotenail for Mg deposition, and 4.5 V vs Mg anodic stability. Solution and interfacial chemistry of the presented Mg electrolytes will be discussed in detail.
Controlling of Dispersion State of Particles in Slurry and Electrochemical Properties of Electrodes
Authors: Kuratani Kentaro , Ishibashi Kaoru , Komoda Yoshiyuki , Hidema Ruri , Suzuki Hiroshi , Kobayashi Hironori
Published: May 2020

The electrode materials which exhibit high capacity have attracted much attention because the capacity of the materials directly commits to the energy density of LIBs and driving miles of EVs. So that, many researchers devote their efforts to find new electrode materials with high capacity such as lithium excess layered oxide, Ni-rich materials and silicon. Electrode manufacturing process, generally consists of (1) preparing slurry, (2) coating the slurry on current collector, (3) drying, (4) pressing steps, is another important issue to achieve LIBs with high energy density.

Compared with numerous reports described with the electrode material development, however, only the limited numbers of papers related to the electrode construction process have been published [1-5]. To shed light the relationship between the electrode construction process and the battery performance is an essential research for obtaining the best performance from electrode materials and assembled LIB cells.

In the present study, we focused our attention on the slurry preparation step among above-mentioned four steps. The slurry preparation is the first step in the electrode construction process, and we recognize the dispersion state of particles achieved during slurry preparation greatly influences the battery performance.

Three different preparation processes were applied to achieve the different dispersion state of particles in slurries, and thus obtained slurries are characterized by rheological measurement. It is found that dispersion process with highly loaded slurry or under high shear flow reduces elastic moduli and that their combination achieved the most dispersed state of the particles among the slurries investigated. X-ray computed tomography unveiled that the electrodes manufactured from these slurries contain the aggregates and the size of aggregates in the electrodes was reduced with the decrease in elastic moduli of slurry. At the discharge current density of 10 mA g–1, these electrodes exhibited 140 mAh g–1 of discharge capacities. At 1000 mA g–1, the electrode prepared from highly loaded slurry maintained 80% of the capacity that obtained at the current density of 10 mA g–1. The capacity of the electrode prepared from the slurry under highly loaded and high shear flow, on the other hand, dropped below 10%, indicated that the electrode from the most dispersed slurry has the worst rate performance.

[Ref.]

1) K. M. Kim et al., J. Power Sources, 83, 108 (1999).

2) E. Ligneel et al., J. Electrochem. Soc., 154, A235 (2007).

3) G.-W. Lee et al., J. Power Sources, 195, 6049 (2010).

4) B. Bitsch et al., J. Power Sources, 265, 81 (2014).

5) S. Lim et al., J. Power Sources, 299, 221 (2015).
In Situ Electrooxidation of Electrolyte Additive to Improve Capacity Retention in Li-Rich Layered Oxide Cathode, Li2RuO3
Authors: Zak Joshua Joseph , See Kimberly A
Published: May 2020

Conventional positive electrode materials for Li-ion technology utilize a Li+ intercalation mechanism charge-balanced by redox on transition metals within an oxide host lattice. Moving forward, multi-electron cathodes that gain capacity by contribution to the redox from the structural anions are of interest for the hybrid intercalation- and conversion-type chemistry during cycling. One such material, Li2RuO3, first studied by Goodenough and coworkers, exhibits high capacity but also a significant capacity loss after the first charge and long-term capacity fade. We suspect the capacity loss is due to structural distortions induced as the lattice accommodates the removal of Li+. Electrolyte additives with tailored chemistry can be an efficient and cost-effective way to stabilize structural changes and promote reversible cycling. Here, in situ, irreversibleelectrooxidation of soluble electrolyte additives at the cathode-electrolyte interface was investigated as a route to stabilizing the cathode surface. Electrooxidation causes dramatically improved capacity retention and stabilizes high-voltage oxidation processes in Li2RuO3. Through understanding how to stabilize structural distortions in Li-rich layered oxide cathodes, we hope to promote reversible cycling near theoretical capacity and target design principles for active electrolyte additives that enhance battery performance.
Bottom-up Au Filling for Metallizations and High Aspect Ratio Features
Authors: Josell Daniel , Ambrozik Stephen , Moffat Thomas P.
Published: May 2020

Bottom-up filling processes for fabrication of void-free, high aspect ratio, micrometer to millimeter size gold interconnects for wide bandgap materials or structures such as diffraction gratings have recently been demonstrated in near-neutral sulfite electrolytes containing micromolar concentrations of bismuth. The processes are highly efficient in time and material, the bottom-up deposition being entirely localized to filling of the recessed features and uniform across patterned substrates. Furthermore, deposition automatically stops under potentiostatic control, exhibiting a tell-tale potential signature upon filling under galvanodynamic control, at a controllable depth within patterned features. This presentation will present feature filling, deposit microstructure and understanding.
A Novel Three-Dimensional High Density Vertical Rram Arrays with Reduced Leakage Current
Authors: Wu Min-Ci , Ting Yi-Hsin , Chen Jui-Yuan , Wu Wen-Wei
Published: May 2020

NAND flash is the most widely used non-volatile memories due to its low cost and rewritable properties. However, some problems exist in NAND flash that need to be solved, such as low writing and reading speed, high operating voltage, and relatively large cell dimensions. Next generation memories, especially resistive random access memory (RRAM) could improve these problems. The technologies of 3D vertical architecture have made a major breakthrough in establishing high-density memory structures. Combined with an array structure, a 3D high density vertical resistive random access memory (VRRAM) cross-point arrays are able to efficiently increase the device density in vertical direction.

In this work, a novel 3D VRRAM arrays which contains two VRRAM cells (Pt/ ZnO/ Al and Pt/ ZnO/ Ti) and one normal layered RRAM (Al/ Al2O3/ Ti) at each cross point were constructed. The Al2O3 based device could operate under a lower compliance current, where contained higher resistance than ZnO based cells. With the controlling of compliance current, the leakage current between VRRAM cells and Al/ Al2O3/ Ti cell could be effectively reduced, therefore, the neighboring cells could be operated independently. We demonstrated the introducing of VRRAM structure could achieve high density advantage in vertical direction, and the adjacent cells in 3D vertical structure could be operated independently with scarcely leakage current. The shrinkage of leakage current enhance the stability of devices and increase the feasibility of high density VRRAM structure applications.

Figure 1
(Invited) Considerations for Storage Batteries
Authors: Ji Xiulei
Published: May 2020

There exists a tremendous demand for new storage capacity. According to BloombergNEF, the global storage capacity excluding pumped hydro storage (PHS) will increase from 9 GW in 2019 to more than 1095 GW by 2040. In order to meet this demand, the market will select the best storage solution based on two metrics: (1) the levelized energy cost (LEC), i.e., the cost for every kWh delivered over the entire lifetime of the storage facility and (2) the safety issues that may cause unaffordable cost. Li-ion batteries (LIBs) may be competitive in LEC one day; however, its flammable nature limits its deployment for massive storage. In this talk, I will talk about five considerations for storage battery chemistries. I will walk through these considerations from a chemical reaction’s point of view, where the reactants consist of electrode materials and ion charge carriers, the reaction medium is the electrolytes, and the battery configurations feature the reactors. Among these factors, the electrode-ion chemical bonding may be the pivot, which reveals the nature of the reaction. Different from Li-ion batteries, where iconicity dominates the electrode-ion interactions, donor-acceptor covalency can be much relevant. Such nuances of chemical bonding are correlated with some surprising kinetic and thermodynamic behaviors in batteries. The understanding of the bonding chemistry under redox conditions may represent the nexus to engender novel solutions.
Aqueous Multivalent Ion Batteries Built on Hydrated Vanadates
Authors: Liu Chaofeng
Published: May 2020

Nonaqueous electrolytes enable a wider operating voltage window and hasten the commercialization of rechargeable batteries with higher energy density. However, their flammability and toxicity cause severe safety issues in practice. Aqueous electrolytes are regarded as the reliable and promising components to improve the safety and power output of batteries. Multivalent ions carry more charges to compensate energy density that is partially sacrificed by the voltage decrease in aqueous batteries in comparison with nonaqueous Li-ion batteries. Divalent cations (Mg2+ and Zn2+) in aqueous electrolyte combined with high capacity of vanadate cathodes provide opportunities and competitions to overcome the limits in current aqueous and nonaqueous systems. We design highly reversible hydrated vanadates and tune the voltage window of aqueous electrolyte to enable the practicability of aqueous multivalent ion batteries (AMBs), and the electrochemistry stayed behind the success of AMBs is also explored.
(Invited) Nasicon-Type NaV2(PO4)3 As a Cathode Material for Calcium-Ion Batteries
Authors: Jeon Boosik , Heo Jongwook W , Hyoung Jooeun , Kwak Hunho H , Lee Dongmin M , Hong Seung-Tae
Published: May 2020

Li-ion batteries (LIBs) have been the most prevailing rechargeable batteries for the last three decades. However, the present LIBs have energy densities close to the theoretical limits, and the Li resources are scarce. Calcium-ion batteries (CIBs) are one of the promising candidates to overcome such limitations of LIBs. The divalency of calcium as the carrier ion can increase the capacity of a host material because two electrons are transferred per carrier ion. The earth-abundance of calcium resources provides potential cost-effectiveness to the products. Calcium has the redox potential (Ca/Ca2+ = −2.87 V vs. SHE) close to Li, potentially leading to a higher cell operating voltage. Calcium ion also has a relatively low effective intercalant-ion charge density (0.49 e/Å3), compared to other multivalent cations such as Mg2+ (1.28 e/Å3), Zn2+ (1.18 e/Å3), and Al3+ (4.55 e/Å3), enabling fast diffusion kinetics for Ca ions in solids as well as in electrolytes. Recent discoveries of reversible plating or alloying of calcium provoked considerable interest in calcium-based rechargeable batteries. Theoretical calculations also predict that the energy barriers for Ca diffusion are lower than other multivalent ions in some structures, and the development of positive materials are anticipated. However, only a few positive materials have been reported so far, only to exhibit low energy-storage capability and poor cyclability. In this work, we report NASICON-type NaV2(PO4)3 as a cathode material for nonaqueous CIBs, with high capacity and voltage with a good cyclability. This work demonstrates experimentally that an oxide material can be a good host structure for Ca diffusion at room temperature with high energy-storage capability.
(Invited) Graphene with Tunable Defects to Provides Fundamental Insight on Sodium Metal Plating Behavior
Authors: Mitlin David
Published: May 2020

This is the first report of a novel directional flow-aided sonochemistry (FAS) exfoliation method to synthesize graphene with nearly ideal structure. The FAS treatment allows for control of graphene structural order and chemical uniformity not possible through prior top-down wet methods. Graphite is exfoliated into single-nm scale thickness graphene that is nearly defect free (at-edge sonication graphene "AES-G") or is highly defective (in-plane sonication graphene "IPS-G"). The AES-G has a Raman G/D band intensity ratio of 14.3 and an XPS derived oxygen content of 1.3 at.%, while the IPS-G has IG/D of 1.6 and oxygen content of 6.2 at.%. Graphene and related carbons are widely employed as templates and protection layers to improve metal plating behavior in sodium and lithium metal battery (SMBs, LMBs) anodes. We then use AES-G and IPS-G to examine the role of structure and chemistry of graphene supports in promoting efficient Na metal cycling. The graphene serves a dual role in stabilizing the Na metal anode, being a nucleation template and serving as a protective layer to keep the metal from severely reacting with the electrolyte. We are the first to demonstrate that graphene defects are actually quite deleterious for efficient Na plating and stripping. AES-G yields state-of-the-art Na performance, with stable cycling at 2 mA/cm2 at 100% Coulombic efficiency (CE), and an areal capacity of 1 mAh/cm2. Meanwhile IPS-G performs on-par with the baseline Cu support in terms of severe charging instability. The explanation is that the defective graphene demonstrates much more copious SEI formation due to its defects and oxygen groups being catalytic. A thicker SEI results in a larger overpotential and worse CE loss during subsequent Na plating/stripping, manifesting in severe mossy metal dendrite growth and periodic electrical shorts. We therefore propose the following design rule for next-generation supports for Na metal: An ideal architecture will not only possess a large surface area for copious preferred heterogenous nucleation, but itself will be non-catalytic for SEI formation.
(Invited) Controlling the Ordering of Na+ and Vacancy By Ti-Doping in P2-Na0.67Co1-XTixO2 for High Energy and Power Density Cathode Materials in Sodium-Ion Batteries
Authors: Kang Seok Mun , Park Jae-Hyuk , Jung Young Hwa , Mun Junyoung , Sung Yung-Eun
Published: May 2020

Sodium-ion batteries (NIBs) for large power sources having kWh or MWh scale of energy are highly interesting alternatives for lithium-ion batteries because of abundant sodium resources in the earth and high chemical similarity between Li and Na ions. However, due to the high atomic weight of Na+ and the low working potential of NIBs, the energy and power densities of NIBs are also required to be improved for wide applications. Despite the similar chemical behavior of Na ions in the rechargeable batteries, the high performance of the active material in NIBs is an essential research- topic for the realization of NIBs. Especially, Na ion having a larger diameter than Li-ion in the P2 type layered structure has a distinct Na+/vacancy ordering behavior presenting multiple voltage plateaus during sodium ion insertion and extraction in the electrochemical cycling. This different behavior from lithium-ion batteries makes the sodium ion diffusion complex in the solid matrix due to the pass-through of various stable Na+/vacancy arrangements.

This presentation covers an improvement in the electrochemical performance of the cathode material, Na0.67Co1-xTixO2 having P2 type crystalline structure by using various amounts of Ti doping to control Na/vacancy ordering for mitigating the Na ion diffusion in the solid matrix as well as for extending the de-sodiation range to 4.4 & 4.5 V vs. Na/Na+. The proposed material having Ti doping presents a highly relieved an electrochemical Na+/vacancy ordering behavior from the that of Na0.67Co1-xO2 having a severe capacity loss at high potential because of irreversible phase transitions. In particular, 10 % Ti-doping in the Co content highly advances the cycleability by showing 115 mAh g-1 at the 100th cycle, as well as the rate capability by reaching 108 mAh g-1 at a current density of 1000 mA g-1. The detail diffusion kinetics and phase behaviors from the prepared materials are investigated by a systematic analysis combination comprising TEM, in-situ XRD, and electrochemical methods.
(Invited) Building Better Batteries in the Solid State
Authors: Mauger Alain , Julien Christain M , Armand Michel , Goodenough John B , Zaghib Karim
Published: May 2020

Most of the current commercialized lithium batteries employ liquid electrolytes, despite their vulnerability to battery fire hazards, because they avoid the formation of dendrites on the anode side, which is commonly encountered in solid-state batteries. In a review two years ago, we focused on the challenges and issues facing lithium metal for solid-state rechargeable batteries (see J. Power Sources 353 (2017) 333-342), pointed to the progress made in addressing this drawback, and concluded that a situation could be envisioned where solid-state batteries would again win over liquid batteries for different applications in the near future. However, an additional drawback of solid-state batteries is the lower ionic conductivity of the electrolyte. Therefore, extensive research efforts have been invested in the last few years to overcome this problem, the reward of which has been significant progress. It is the purpose of this review to report these recent works and the state-of-the-art on solid electrolytes. In addition to solid electrolytes stricto sensu, there are other electrolytes that are mainly solids, but with some added liquid. In some cases, the amount of liquid added is only on the microliter scale; the addition of liquid is aimed at only improving the contact between a solid-state electrolyte and an electrode, for instance. In some other cases, the amount of liquid is larger, as in the case of gel polymers. It is also an acceptable solution if the amount of liquid is small enough to maintain the safety of the cell; such cases are also considered in this review. Different chemistries are examined, including not only Li-air, Li-O2, and Li-S, but also sodium-ion batteries, which are also subject to intensive research. The challenges toward commercialization are also considered.
The Addition of Powders in Solid-State Electrolyte Lithium Battery
Authors: Liu Shang-En , Hsueh Tien-Hsiang , Wang Min-Chuan
Published: May 2020

The solid-state lithium batteries had attracted lots of research and industry efforts in past decades. The advantages of developing solid-state lithium batteries are safety and higher energy density; however, the poor ionic conductivity is the toughest problem. In order to solve this problem, we utilized three different ceramic powders added in our polymer electrolytes. We used galvanostatic charging/discharging, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) to measure the electrical characteristics of TiO2-SiO2 core-shell, ZrO2 and BaTiO3 nanoparticles added polymer electrolytes, respectively. The results showed the ionic conductivity of the 1 wt.% TiO2-SiO2 core-shell added polymer electrolyte was 1.8×10-4 S/cm, which was 12% more than the polymer electrolyte without adding nanoparticles. The TiO2-SiO2 core-shell nanoparticles added polymer electrolyte also showed faster charge transfer speed than other polymer electrolytes. The capacity retention was 54% at 1C-rate for the polymer electrolyte with 1 wt.% TiO2-SiO2 core-shell nanoparticles, which had the best performance at high C-rate.

Figure 1
Stabilizing Polymer-Based Solid-State Electrolytes with 4 V Class Cathodes: From Interface Modification to Electrode Designs
Authors: Liang Jianneng , Yang Xiaofei , Sun Andy Xueliang
Published: May 2020

Developing safe solid-state lithium batteries with high-energy-density is important for the application in electric vehicles (EVs). Nowadays, solid-state batteries (SSBs) with polymer-based solid-state electrolyte (SSE) is one of the most promising candidates for the application in EVs. However, SSEs based on polyethylene oxide (PEO) and lithium salt complex delivers poor electrochemical performance in 4 V class high-energy-density cathodes such as lithium cobalt oxide (LiCoO2) and lithium nickel manganese cobalt oxide (NMC). This is because PEO has low electrochemical oxidation window which is lower than 3.8 V vs.Li/Li+.[1] This abstract mainly focus on developing several strategies for stabilizing polymer-based SSEs with 4 V class cathodes including interface modification to electrode designs.

Firstly, inspired by previous reports that coating can enhance the cycling performance of SSBs with polymer-based SSE,[2] we applied atomic layer deposition (ALD), a versatile chemical deposition technique which is capable to deposit uniform thin film with controllable thickness at low temperature,[3] for coating cathode to stabilize the polymer-based SSE/4 V class cathode interface under high voltage charge/discharge processes. The coating effect on conductive carbon, active materials, and electrode surface was studied and compared. It is found that carbon is detrimental for the decomposition of polymer-based SSE and the protection of SSE/carbon interface can effectively enhance the performance of 4 V class solid polymer batteries.[4]

Secondly, the electrode design is critical for high performance high-energy-density solid polymer batteries. Using freeze-drying method, we had prepared a high-areal-loading cathode for solid polymer batteries with excellent electrochemical performance. This is because the vertically aligned porous electrode can facilitate the Li+ ion transport within the thick electrode.[5] Also, the binder effect in 4 V class solid polymer batteries is carefully studied. Various binders including PEO, polyvinylidene fluoride (PVDF) etc. were applied in 4 V class solid polymer batteries. And the mechanism had been studied by synchrotron X-ray absorption and X-ray photoelectron spectroscopy.[6]

References

[1] Y. Xia, T. Sakai et al., J. Power Sources, 2001, 92, 234-243

[2] H. Miyashiro, M. Wakihara et al., Chem. Mater. 2005, 17, 23, 5603-5605; S. Seki, T Iwahori et al., Chem. Mater. 2005, 17, 8, 2041-2045; Q. Yang, L. Chen et al., J. Power Source, 2018, 388, 65-70.

[3] Y. Zhao, K. Zheng, X. Sun, Joule 2018, 2, 1-22; Y. Zhao, X. Sun, ACS Energy Lett. 2018, 3, 899−914; J. Liu and X. Sun, Nanotechnology 2015, 26, 024001;

[4] J. Liang, X. Sun et al., J. Mater. Chem. A, 2019, submitted; J. Liang, X. Sun et al., 2019, to be submitted;

[5] X. Yang, J. Liang, X. Sun et al., Nano Energy, 2019, 61, 567-575568;

[6] J. Liang, X. Sun et al., 2019, to be submitted
A Mechanistic Understanding of Lithium Ion Transport in Ternary Ionic Liquid Electrolytes
Authors: Wettstein Alina , Diddens Diddo , Heuer Andreas
Published: May 2020

With regard to methodologically enhancing the electrolyte functionality, and hence the ionic conductivity as a crucial indicator, a profound understanding of the correlated ion motion is essential. For binary ionic liquid systems it has been shown that the motional coupling between ions is determined to a large extent by the conservation of momentum, concurring with simple theoretical relations for transference numbers that serve as a guideline for optimizing the electrolyte [1,2]. Inspired by this work, we perform Molecular Dynamics (MD) simulations to unravel the complex, and rather counterintuitive, interplay of dynamical electrostatic correlations in a ternary ionic liquid - lithium salt mixture, which contribute to the overall conductivity. Considering the environmental sustainability of the electrolyte mixture in the battery context as main scope of application, we choose three anions with reduced toxic fluorine content for this study (bis(trifluormethanesulfonyl)imide (TFSI), trifluormethanesulfonyl-N-cyanoamide (TFSAM) and dicyanamide (DCA)) and study the influence of anion structure on transport behavior. From systematic analysis of the distance- and time-dependent correlational quantities we try to identify key parameters that quantify the microscopic transport properties and hence might serve as a constructive optimization concept.

[1] H. Kashyap et al., J. Phys. Chem. B, 2011, 115 (45), pp 13212–13221

[2] D. Diddens, V. Lesch and A. Heuer, Correlated Motion in Ionic Liquids. To be submitted., 2019
A New Glass Forming Electrolyte Based on Lithium Glycerolate
Authors: Di Noto Vito , Pagot Gioele , Vezzù Keti , Nale Angeloclaudio , Negro Enrico , Pace Giuseppe
Published: May 2020

The study of the interplay between structure and conductivity in lithium-conducting electrolytes is a pivotal point for the development of future secondary batteries [1]. The use of Glycerol as a low molecular weight component in electrolytes is particularly interesting due to its glass-forming behavior and low glass transition temperature (-78.5°C). In addition, a high flexibility of the alkyl backbone chain and the well-known capability of oxygen functionalities to coordinate lithium cations make Glycerol very appealing as ion-conducting media as well as building block to obtain hybrid polymer electrolytes [2].

On this basis a family of eleven electrolytes based on Lithium Glycerolate with general formula C3H8-xO3Lix, where 0 ≤ x ≤ 1, is prepared and investigated [3]. In these electrolytes the Glycerolate (C3H8-xO3
x-) component acts as a large and flexible macro-anion which is able to provide a high single-ion conductivity to the material (8.36∙10-5 S∙cm-1 at 20°C and 1.55∙10-2 S∙cm-1 at 150°C for x = 0.25).

Finally, the Glycerol∙∙∙Li+ interactions in these electrolytes are studied on T and x, with a particular reference to the detection of: a) macro-anion coordination sites; and b) the secondary structure of Glycerol chains. Insights on the long-range charge transfer mechanism and Glycerol relaxation events are also discussed.

These studies are carried out by Inductively-Coupled Plasma Atomic Emission Spectroscopy, IR and Raman spectroscopies, DSC, TGA, and Broadband Electrical Spectroscopy.

References

[1] V. Di Noto, S. Lavina, G. A. Giffin, E. Negro, B. Scrosati, Electrochim. Acta 57 (2011) 4-13.

[2] V. Di Noto, M. Vittadello, S. G. Greenbaum, S. Suarez, K. Kano, T. Furukawa, The Journal of Physical Chemistry B 108 (2004) 18832-18844.

[3] G. Pagot, S. Tonello, K. Vezzù, V. Di Noto, Batteries 4 (2018) 41.
(Invited) Solid Halide Electrolytes for All-Solid-State Lithium Ion Batteries
Authors: Asano Tetsuya , Sakaida Masashi , Sakai Akihiro , Miyazaki Akinobu , Hasegawa Shinya
Published: May 2020

In order to realize all-solid-state batteries (ASSBs) with high energy density and high-rate charging/discharging capability that surpass conventional LIBs, development of solid electrolytes (SEs) is one of the utmost remaining issues. The difficulty is that SEs need to satisfy stringent requirements particularly for large scale applications; not only high ionic conductivity, but also high electrochemical stability, chemical stability, and deformability. However, neither sulfide nor oxide SEs satisfy all these requirements by themselves so far.

Here, we propose that, considering the electronic and chemical nature of halide anions, halide solid electrolytes (HSEs) have potential to satisfy all the above requirements, and demonstrated that HSEs are indeed suited as an SE material for ASSB application [Ref].

The lithium ionic conductivity of cold-pressed powders of the HSEs we developed surpassed 1 mS/cm at room temperature without any additional grain-boundary resistance. Such high ionic conductivity was realized even with close-packed anion sublattices whose ion pathways are unlike those of sulfide or oxide SEs, indicating that the design consideration for ionic conductors varies depeding on the material systems. The bulk-type ASSBs using these new HSE materials exhibited excellent charge/discharge performance with 4 V class cathode active materials without any extra coating; the initial coulomb efficiency over 94% and low interfacial resistance to be less than 10 Ωcm2, indicating high oxidation stability of HSE materials. Moreover, by appropriate selection of cation/anion pairs, electrochemical stability of HSE can be improved so that HSE can work with the anode active materials with Li-metal potential such as graphite.

All these characteristics of halide materials clearly indicate that HSEs are promising candidate for ASSB application, in addition to sulfides and oxides, for large scale deployment.

[Ref] T. Asano et al., Adv. Mater. 2018, 30, 1803075.
A New Method for Measuring Transference Number Using Raman Spectroscopy
Authors: Fawdon Jack , La Mantia Fabio , Pasta Mauro
Published: May 2020

The successful use of lithium metal as the negative electrode in high-energy density batteries is dependent on the effective suppression of dendritic growth during charging.1 A key electrolyte property for mitigating dendritic growth is the transference number, which describes the movement of one ion in relation to the other ions in solution.2 Traditionally, the agreed method for measuring the transference number has been the Hittorf method,3 but with the requirement of a large volume of electrolyte and the difficulty of separator inclusion, it does not imitate a real battery application. The popular polarisation methods including the so-called Bruce-Vincent method4 and the pure Electrochemical Impedance Spectroscopy method5 addresses this problem by including separators and only using small amounts of electrolyte. However, these methods assume ideality, which can often lead to the incorrect value of transference number especially at high concentrations or using ionic liquid electrolytes.

We propose a new method for measuring the transference number, using Raman Spectroscopy, which closely imitates a real cell by the inclusion of a separator and does not assume ideality. We believe this facile and powerful new experiment is implementable in both academia and industry to understand how novel electrolyte’s transference number is influencing the concentration gradient and also dendrite growth.

References

1. Cheng, X. B., Zhang, R., Zhao, C. Z. & Zhang, Q. Toward Safe Lithium Metal Anode in Rechargeable Batteries: A Review. Chem. Rev.
117, 10403–10473 (2017).

2. Brissot, C., Rosso, M., Chazalviel, J. N. & Lascaud, S. Dendritic growth mechanisms in lithium/polymer cells. J. Power Sources
81, 925–929 (1999).

3. Valoen, L. O. & Reimers, J. N. Transport Properties of LiPF6-Based Li-Ion Battery Electrolytes. J. Electrochem. Soc.
152, A882 (2005).

4. Bruce, P. G. & Vincent, C. A. Steady state current flow in solid binary electrolyte cells. J. Electroanal. Chem.
225, 1–17 (1987).

5. Ravn Sørensen, P. & Jacobsen, T. Conductivity, charge transfer and transport number-an ac-investigation of the polymer electrolyte LiSCN-poly(ethyleneoxide). Electrochim. Acta
27, 1671–1675 (1982).
Ta-Doped Li7La3Zr2O12 Solid-State Electrolytes with Cubic Structure and High Density Synthesized By Self-Consolidated Method
Authors: Zhao Pengcheng
Published: May 2020

Lithium ion battery (LIB) has become the dominant storage device for commercial wireless applications. However, its safety issues still haven’t been resolved due to its liquid organic electrolytes, which are volatile and flammable. All-solid-state LIB is viewed as a thorough solution for the safety issues. Instead of liquid electrolytes, all-solid-state LIB employs stable inorganic solid-state electrolytes with super ionic conductivity as both separators and ion conductors. Among current inorganic solid-state electrolytes, garnet-like oxides such as cubic LLZO (Li7La3Zr2O12) are the only candidates exhibiting the unique combination of high ionic conductivity and excellent stability against Li metal. For inorganic solid-state electrolytes, higher density generally leads to higher ionic conductivity. Therefore, most researchers prefer ultra-high pressure technology such as cold isostatic pressing (CIP) or hot isostatic pressing (HIP) to obtain high-density electrolytes. However, such preparation processes are too complicated and impractical for large-scale production because of the ultra-high pressure and poor productivity. Moreover, for the inhibition of intergranularly propagation of Li along the grain boundaries, LLZO pellets prepared by conventional high-pressure methods have been reported to be invalid due to their morphology of small particles and numerous grain boundaries. In order to overcome the shortages of conventional high-pressure methods, a novel method defined as self-consolidation was developed for the preparation of LLZO electrolytes in our previous work. The surface tension deriving from the interstitial “liquid” phase is utilized as the intrinsic power for the self-consolidation of ceramic LLZO particles. Not any pressing assistance is employed in the entire process. As a result, the preparation process is dramatically simplified. In this paper, self-consolidation method is tried to synthesize Ta-doped LLZO solid-state electrolytes. Dense LLZO with a solitary cubic phase and a high relative density about 96% was prepared successfully. At 30 oC, the maximum total and bulk ionic conductivities are about 2.74×10-4 and 1.17×10-3 S cm-1, respectively. The results show that, even though the preparation process is dramatically simplified, the sample’s relative density and ionic conductivity are comparable to the highest reported values of the samples prepared by traditional pressing methods. Meanwhile, the morphology and ionic conductivity of the sintered samples are promoted. This work verifies that self-consolidation strategy is effective, reliable, and productive for the preparation of cubic LLZO electrolytes, which would significantly facilitate the development of ceramic electrolyte membrane technology.

Figure 1