bluuebunny/crossref_metadata_2025 huggingface dataset:
High-Energy Lithium/SeS2 Batteries with Hierarchical Nanocomposite Cathode and Ionic Liquid-Based Electrolytes
Authors: Dong Panpan , Lee Jung-In , Cha Younghwan , Zhang Xiahui , Song Min-Kyu
Published: February 2020

Selenium disulfide (SeS2)-based composites have received much attention as a promising cathode material for high-energy lithium metal batteries due to their higher theoretical capacity (1342 mAh g−1) than that (675 mAh g−1) of selenium and a less significant shuttle effect than that of sulfur.[1] However, the biggest challenges faced by Li/SeS2 batteries are (1) the development of high-performance cathodes that can maintain the functional interface during cycling and (2) the identification of suitable electrolytes that can allow good cyclability without the degradation of lithium metal anodes. It has been reported that an ionic liquid, N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, i.e. Py14TFSI, can be used as co-solvent in ether-based electrolytes to form high-quality protection layer on lithium metal.[2] In this study, an effective strategy for developing high-performance Li/SeS2 batteries is introduced via a synergistic enhancement comprising the effective cathode design and the lithium anode protection in Py14TFSI containing electrolytes. We found that the hierarchical SeS2@carbon nanocomposites, confirmed by X-ray nano-computed tomography, facilitated Li-ion transportation and enhanced the electrochemical utilization of SeS2, enabling the improved rate capability of Li/SeS2 battery. Furthermore, the systematic studies on the morphological change as well as the electrochemical stability of lithium anode indicate that Py14TFSI-LiNO3­-containing electrolytes could effectively suppress the shuttle effect and protect lithium metal by forming a stable and LiF-dominated solid-electrolyte-interphase layer, leading to much improved Coulombic efficiency and cyclability of Li/SeS2 batteries. These results underscore a synergistic approach toward the development of high-energy Li/SeS2 batteries with long cycle life.

[1] a) A. Abouimrane, D. Dambournet, K. W. Chapman, P. J. Chupas, W. Weng, K. Amine, J. Am. Chem. Soc.
2012, 134, 4505-4508; b) Y. Cui, A. Abouimrane, J. Lu, T. Bolin, Y. Ren, W. Weng, C. Sun, V. A. Maroni, S. M. Heald, K. Amine, J. Am. Chem. Soc.
2013, 135, 8047-8056.

[2] J. Zheng, M. Gu, H. Chen, P. Meduri, M. H. Engelhard, J.-G. Zhang, J. Liu, J. Xiao, Journal of Materials Chemistry A
2013, 1, 8464.

Figure 1
Diagnostics for Failure Modes in Non-Aqueous Flow Batteries
Authors: Pratt Harry D. , Small Leo J. , Anderson Travis M.
Published: February 2020

Expansion of promising, non-aqueous flow battery chemistries may increase energy densities, lower costs, and ultimately increase penetration of energy storage technologies into electric grids throughout the world. However, significant research efforts are required to understand their potential relative to the well-studied aqueous vanadium and organic systems. Among the most promising non-aqueous chemistries are those based on the bipyridine metal coordination complexes. Like their aqueous counterparts, they are very susceptible to crossover. Having a key mechanistic understanding of the role that the electrolytes, solvents, and membranes play in crossover is critical to designing longer lasting batteries. Recently, we examined the role of the membrane in crossover using the aqueous organic methylviologen and TEMPO molecules and five commercially available anion exchange membranes. Capacities between the batteries were found to differ by >50% after 100 cycles with the different membranes. The capacity loss was attributed to crossover across the membrane and was dominated by mechanisms including diffusion, migration, and electroosmotic drag.

For this study, we have investigated the role of not just the membrane on crossover, but the effects that both the electrolyte and solvents have on battery performance as well. Conditions were chosen to prevent crossover through both physical and chemical variabilities. This included using bulkier cations and anions in the electrolyte as well varying the dielectric constant of the solvents. Membranes were chosen based on chemical compatibility, tortuosity, and physical robustness. Collectively, the results have informed us on how to effectively design membranes within the parameters of electrolyte and solvent selection.

Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
Impacts of Microstructures on the Ionic Diffusivity of Solid Electrolytes: Mesoscale Modeling Approach
Authors: Heo Tae Wook , Grieder Andrew , Wan Liwen , Adelstein Nicole , Wood Brandon C.
Published: February 2020

Development of viable solid electrolytes is key for commercial adoption of all-solid-state batteries that can solve critical issues associated with electrochemical stability and safety for wider scale applications of the current battery technology. Recent years have seen the emergence of several solid electrolyte candidates with high ionic conductivity; however, practical processing and synthesis routes often generate internal interfaces that can disrupt conduction channels in these materials. In this talk, we will present our development of an efficient mesoscopic computational method for predicting the effective diffusivity through a solid electrolyte with a complex polycrystalline or polygranular microstructure. Our method considers simultaneous interfacial and bulk conduction modes, going far beyond simplified circuit descriptions to account for factors such as orientational variation of crystallite domains and the effects of interfacial strain. Using the Li7La3Zr2O12 (LLZO) solid electrolyte as a model system, we show how our simulation framework can be parameterized using a multiscale approach that derives digital microstructures from phase-field simulations and diffusivity tensors of reference phases and boundaries from molecular dynamics simulations. Simulations of the effective diffusivity of polycrystalline LLZO are applied to investigate the relationship between relevant microstructural features and ionic conductivity, with a focus on topological features of grains and grain networks. Using several instances, we will discuss a high sensitivity to these features, highlighting the need to account for microstructure when assessing mass transport in LLZO and related solid electrolyte materials.

This work of was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
(Invited) Multiscale Chemical Complexities in Layered Oxides for Sodium Ion Batteries
Authors: Lin Feng
Published: February 2020

Applications such as large-scale stationary energy storage call for significantly reduced cost of batteries. Sodium ion batteries offer one of the most feasible alternatives to meet these particular demands. Layered oxide materials are regarded as a technologically important class of cathode materials due to their excellent reversibility in cycling sodium ions and relatively smaller degree of lattice volume change. Various transition metal ions can be incorporated in the transition metal layer of sodium layered oxides giving considerable flexibility to the choice of the transition metals. The different choices of transition metals make it challenging to obtain the perfectly homogeneous distribution in multielemental sodium layered oxide materials because of their differences in the ionic size and electronic properties. However, how much does the homogeneous elemental distribution matter in the battery performance? What are the chemical and structural transformations of heterogeneous layered oxides during charging and discharging? In this presentation, we will discuss our recent progress in understanding the multiscale heterogeneity in sodium layered oxide materials. First, we will establish the relationship between the cathode surface chemistry and the sodium full-cell electrochemistry through a range of complementary advanced spectroscopic and imaging diagnostic techniques. Second, we will highlight our effort in decoupling the multiscale electrochemistry in sodium layered oxide materials. We will illustrate that engineering the three-dimensional distribution of metal cations in electrode particles can take advantage of the depth-dependent charging mechanisms thus empowering superior battery performance.
Reactive Wetting of Atomic Layer Deposition Al2O3 By Molten Lithium Metal
Authors: Gong Yunhui , Fu Zhezhen , Zhang Lei , Hamann Tanner R. , Wachsman Eric D.
Published: February 2020

Oxide coating presents a promising methodology to enable reactive wetting of solid-state garnet electrolyte by molten lithium metal. The resulting intimate contact allows effective lithium-ion migration at the garnet/lithium metal interface. Although changing in coating composition by the interfacial reaction has been previously revealed, the transition in chemistry, structure, topography and mechanical performance of the contact coating area remain unclear. Here, a combination of impedance spectroscopy, scanning electron microscope, time-of-flight secondary ion mass spectrometry and nanoindentation is devoted to illustrating and discussing the effect of the interfacial reaction in altering the properties of atomic layer deposition alumina coating layer. These findings provide unique insight into the mechanism of the reactive wetting of oxide coating by molten lithium metal, thereby, enabling design of more effective lithium metal-solid electrolyte interfaces.
(Invited) Cooperative Ion Migration in Li-Ion Conducting Glasses
Authors: Siegel Donald J
Published: February 2020

Sulfur-based glasses have reemerged as promising candidates for use as solid electrolytes in Li-based batteries. Nevertheless, due to their amorphous structure, the ion migration mechanisms that underlie their high Li-ion conductivity remain poorly understood. The present study employs ab initio molecular dynamics to reveal the local structure and migration mechanisms in the prototype Li-ion conducting glass, 0.75 Li2S- 0.25 P2S5. A computational model of the amorphous structure was generated, and is shown to closely match the measured neutron weighted pair distribution. The structure data indicates that Li-ions experience a range of coordination environments, with typical Li-S coordination numbers between 3 to 5. Lithium is observed to migrate via correlated, 'string-like' events involving multiple adjacent cations. Furthermore, these migration events involve the dynamic participation of the PS4anions, which undergo simultaneous rotation and translational displacements. This behavior contrasts with that of the Li3PS4 crystalline analogue, were rotations and translations of the anions during migration events are severely limited. These observations provide direct evidence of the importance of anion dynamics on cation mobility in fast ion conductors.
Experimental and Theoretical Analysis of Li-Stuffed Garnet-Type Electrolytes
Authors: Palakkathodi Kammampata Sanoop , Yamada Hirotoshi , Ito Tomoko , Paul Reginald , Thangadurai Venkataraman
Published: February 2020

Rechargeable lithium-ion batteries (LIBs) are one of the dominant technologies for electrochemical energy storage. They are widely used in portable electronics, electrical vehicles, and large-scale energy storage systems. Current LIBs use organic polymer based electrolytes and they have several problems such as dendrite formation, flammability and leakage.1 Therefore, there is much attention on developing a solid-state Li-ion electrolyte that is thermally and chemically stable. Among the various inorganic solid Li-ion conducting electrolytes, garnet structured compounds have shown great promise as potential electrolytes for all-solid-state lithium batteries due to their high ionic conductivities (10-4 S/cm), compatibility with Li metal anode, and wide electrochemical window (~ 6V vs Li/Li+).2 The present study reports a comparison of the experimental and theoretical data of garnet type Li-ion solid electrolytes. The solid electrolytes, Li6.5La2.9A0.1Ta0.6Zr1.4O12 (A = Ca, Sr, Ba) were prepared by conventional solid state sintering and spark plasma sintering method. The formation of the ‘‘single-phase’’ garnet-type structure was analysed by powder X-ray diffraction (PXRD). Li-ion conductivity was determined using electrochemical impedance spectroscopy (EIS) and all the members have exhibited ionic conductivity in the order of 104 S/cm at 25 °C. Interfacial resistance of the garnet samples and Li metal was measured using EIS and the interfacial stability of the same was confirmed by DC galvanostatic cycling experiments. Li-ion conductivity and activation energy of the prepared compounds were also calculated using a statistical mechanical approach and the estimated values are in good agreement with the experimental values.

References

1. S. Chen, K. Wen, J. Fan, Y. Bando and D. Golberg, J. Mater. Chem. A, 2018, 6, 11631–11663.

2. R. Murugan, V. Thangadurai and W. Weppner, Angew. Chem. Int. Ed., 2007, 46, 7778–7781.
Li Garnet Dopant Stability Against Li Metal: A TOF-SIMS Study
Authors: Zhang Lei , Gong Yunhui , Hamann Tanner R. , Wachsman Eric D.
Published: February 2020

Solid-state lithium batteries (SSLiBs) has been extensively studied in the past five years. The widely studied solid-state electrolytes (SSEs) includes LiSICON [1], NASICON-type Li conductors [2], perovskites [3] and garnets [4]. It is realized that garnet electrolyte is the most promising oxide electrolyte, due to its high Li-ion conductivity, stability with high voltage Li cathodes and Li anode. However, recently there has been reports [5, 6] on metal element reduction in certain garnet composition. Metal element reduction can lead to electronic conductivity, which is detrimental to cell performance. The reduction reaction is mostly likely to occur at grain boundaries. Since grain boundary is very thin and Li element is hard to detect, limited techniques can characterize the reduction reaction. Fudong and co-workers [5] applied neutron depth profiling technique to study Li content variation. Yisi and co-workers [6] conducted advanced XPS technique to study reduction on garnet grain surface.

TOF-SIMS is surface sensitive technique with nano scale resolution. Herein, we will present our TOF-SIMS study on garnet dopant stability against Li metal. It is found that Nb dopant is not stable to Li metal. Nb doped garnet changes color upon contacting Li metal. This color change progress through the whole ceramic sample. EIS results show that resistance continues increase while the reaction progress. TOF-SIMS results indicate Nb element segregates to grain boundary and presents a different coordination at grain boundary than in bulk garnet.

Reference:

[1] Xu, X. et al. Chem. Mater. 23, 3798-3804 (2011).

[2] Feng, J. K. et al. Mater. Technol. 28, 276-279 (2013).

[3] Ihlefeld, J. F. et al. Adv. Mater. 23, 5663-5667 (2011).

[4] Thangadurai, V. et al. Chem. Soc. Rev. 43, 4714-4727 (2014).

[5] Han, F. et al. Nature Energy 4, 187-196 (2019).

[6] Zhu, Y. et al. Adv. Energy Mater. 9, 1803440 (2019).

Figure 1
Lithium Electrodeposition at the Solid Electrolyte and Lithium Metal Interface
Authors: Tewari Deepti , Mukherjee Partha P.
Published: February 2020

Lithium metal anodes are desirable because of high redox potential and large specific capacity. However, during charging of lithium metal anodes, dendritic growth can occur at the lithium metal and liquid electrolyte interface. Dendritic growth at the interface is detrimental to battery performance and also a safety issue. Solid electrolytes have been proposed as alternative to liquid electrolytes for all-solid-state batteries. This study is aimed at understanding lithium electrodeposition characteristics for inorganic solid electrolyte and lithium metal interfaces. The deposition of lithium will depend upon the nature of the interface, i.e., the orientation and misfit of lithium and solid electrolyte crystal lattices. The deposition will also depend upon the mechanical properties of the solid electrolyte. This presentation will focus on mesoscale understanding of the nature of such electrodeposition.
Prediction of Solvents and Non-Solvents for Polymers Using Machine Learning Techniques
Authors: Venkatram Shruti , Kim Chiho , Chandrasekaran Anand , Ramprasad Rampi
Published: February 2020

As renewable energy sources are increasingly gaining traction as an alternative to scarce fossil fuels, exploratory research on energy storage devices which are reliable, cost-effective and have low energy losses has become prolific. This has spearheaded the development of solid polymer electrolytes for safer lithium-ion batteries with comparable properties as conventional liquid electrolyte-based lithium-ion batteries. Synthesizing solid polymer electrolytes involves preparing an electrolyte film from a solution of polymer and Li-ion salts in an appropriate solvent. Identifying appropriate solvents for the polymer solution is usually done by trial-and-error, and therefore, is time-consuming. To mitigate this problem, quantitative measures of solvent-polymer miscibility known as solubility parameters have been developed in the past. In the present study, we first assessed the performance of the Hildebrand and Hansen solubility parameters to predict solvents and non-solvents for a set of benchmark polymers. Based on the results of the assessment, a machine learning model was trained on a dataset of known polymer Hildebrand solubility parameters to predict the solubility parameter of a queried polymer. Matching the predicted value with known solvent solubility parameters was then utilized to identify suitable solvents and non-solvents for the queried polymer. This capability has been implemented at www.polymergenome.org.
Polyacrylonitrile and Polypropylene Carbonate Blended Solid Polymer Electrolytes for Application Toward Solid State Lithium Ion Batteries
Authors: LaCoste Jed Donavan , Fei Ling , He Zizhou , Matherne Drew , Banjara Saraj
Published: February 2020

Lithium ion batteries are promising as energy storage devices because of their high energy density; however, current technology for lithium ion batteries is not safe for large scale applications and general use. Traditional lithium ion batteries use an organic liquid electrolyte to transport lithium ions between electrodes. Organic solvents used in lithium ion batteries, such as diethyl carbonate, are highly flammable and volatile. Safety issues arise when the battery heats from charging, discharging, or from dendrite formation in the cell. When this occurs, the battery can potentially ignite and pose a safety hazard. In this work, the research focus is developing blended solid polymer electrolytes for solid state lithium ion batteries. Polypropylene carbonate (PPC), an amorphous polymer, and polyacrylonitrile (PAN), a semi-crystalline polymer, have been shown to be individually effective for solid state lithium ion batteries. In this work, we fabricate novel PAN and PPC blended solid polymer electrolytes complexed with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). Furthermore, LiTFSI acts as both a source of lithium ions and as a plasticizer for the polymers, thus increasing the amorphous character of the polymer blend. Lithium ion conductivity is higher in amorphous electrolytes than in semi-crystalline solid polymer electrolytes. Solution casting, a commonly used technique for electrolyte fabrication, is used to control the thickness of the electrolyte film by varying the amount of solution added to the casting plate. During solution casting, the PPC and PAN undergo phase separation, this increases the number of micro-pores in the electrolyte. It has been shown that micro-pores improve the ionic conductivity of solid electrolytes. Upon evaporative drying of the solid polymer electrolytes, several tests are performed to characterize the electrolyte material as test well as battery performance.
(Invited) A Trip to Oz and a Look behind the Curtain: Solid-State Batteries
Authors: Bonnick Patrick , Muldoon John
Published: February 2020

Solid-state batteries have garnered much attention due to their numerous benefits over cells containing liquid electrolytes. For example, thermally stable solid-state electrolytes allow for a paradigm shift in battery-pack design by simplifying thermal management and allowing bipolar stacking. The elimination of cell packaging and thermal management components would dramatically improve the energy density beyond what is possible for a Li-ion battery containing liquid electrolyte. In particular, lithium thiophosphates (LTP) tend to have higher Li+-conductivities and are more easily processed than oxide solid-electrolytes, and so they are being considered as a non-volatile and thermally stable solid electrolyte for lithium-ion batteries. From our perspective, we will present some of the challenges associated with solid-state batteries and discuss the research of next generation solid-state technologies.
(Invited) Voids at the Alkali Metal / Solid Electrolyte Interface
Authors: Bruce Peter G. , Kasemchainan Jitti , Zekoll Stefanie , Spencer Jolly Dominic , Hartley Gareth , Ning Ziyang , Adamson Paul , Pasta Mauro
Published: February 2020

Implementing alkali metal anodes and replacing flammable liquid electrolytes with solids promises to deliver higher energy densities and greater safety than conventional Li-ion batteries. However, challenges at the interfaces must be addressed to realise this potential. Alkali metal dendrite growth, even at modest rates and even when paired with dense, well-sintered solid electrolytes, leads to short circuits and cell failure. We have investigated the effect of cycling conditions on the formation of voids and dendrites under controlled applied pressure. The results reveal the significance of plating/stripping current densities and pressure on cell failure. We propose a model for void accumulation and its effect on dendrite formation. These results and their implications for the operation of a failure free all-solid-state battery will be discussed.
Probing Ion Solvation and Transport in Single-Digit Nanopores with First-Principles Simulations
Authors: Pham Tuan Anh , Zhan Cheng , Schwegler Eric
Published: February 2020

Carbon nanotubes underpin a large array of materials systems and technological applications, including supercapacitors and water desalination. In these devices, understanding of the ion behavior is essential for predicting and optimizing the performance; however, many mechanistic details remain enigmatic. These include transport and solvation properties of the ions, and how they are governed by the degree of confinement. Here, we employ first-principles simulations to unravel key features of the solvation structure of several common ions at the interface with graphitic interface and under confinement within single-digit nanopores. We find that polarizable ions generally exhibit a stronger adsorption at graphitic interfaces and these effects are found to be significantly enhanced under confinement. In addition, we find that confinement significantly influences ion selectivity and transport, i.e., ions with a small radius are found to yield a notably larger energy barrier to reach the pore entrance. Our study therefore points to the complex interplay between confinement and specific ion effects, which has broad implications in optimizing CNTs for ion selectivity and energy storage.
Development of Bimetallic Non-Platinum Group Metal Catalysts Based on Metal Organic Framework Precursors
Authors: LaRochelle Richard Lynne , Jiao Li , Liu Ershuai , Jia Qingying
Published: February 2020

It has been postulated that platinum group metal free (PGM-free) catalysts for the oxygen reduction reaction (ORR) must meet four criteria: metal, carbon, nitrogen, and pyrolysis. Results from multiple studies indicate that metals surrounded by four pyridinic nitrogen atoms form at least part of the active site. Other groups have demonstrated enhanced activity in bimetallic catalysts using first and second-row non-PGM transition metals in metal-nitrogen-carbon (M-N4-C) coordination environments. The precise nature of the active site remains under debate. Many permutations of metal, nitrogen, and carbon are formed during pyrolysis, only a few of which are active. In nature, however, there is no known example of four electron reduction of oxygen at a single metal center. It may be that only multiple-metal centers, metals situated close enough to work cooperatively, are able to catalyze ORR. It stands to reason that the greater the number of M-N4-C sites formed, the greater the probability of producing centers close to one another. However, nanoparticle formation tends to compete as the metal content increases. The present research focuses on the use of zeolitic imidazolate frameworks (ZIFs), a subset of metal organic frameworks, as catalyst precursors. ZIFs are of interest because they are highly porous, contain a high density of M-N4-C centers, and are simple to prepare. Cobalt doping in ZIF precursors affects the porosity and graphitization of the pyrolyzed material. This research investigates the effect of cobalt doping level in ZIF precursors and non-PGM metal pairs (e.g. cobalt adjacent to iron) on catalytic activity. It is hypothesized that graphitization formed during pyrolysis will facilitate the cooperation of proximal metal sites in electron transfer to oxygen. This will be investigated by evaluating bimetallic Co-containing catalysts in ORR by varying the degree of graphitization while holding the ratio of Co and another metal (e.g. iron) constant. Comparison with similar catalysts prepared from amorphous ZIF precursors will elucidate the importance of local carbon structure in electron transfer between metal centers.
Tuning the Performance of Conversion Coatings with Various Additives
Authors: Kumar Kuldeep , Bezer Silvia
Published: February 2020

Traditionally, conversion coatings based on metal phosphates and chromium based species were extensively used in industrial coating processes to provide anti-corrosion properties to metal substrates (e.g. AA6111, steel). Due to increasing environmental constraints, new solutions based on titanium and zirconium species are currently being commercialized around the world.

The growth of conversion coatings on metal alloys exhibits oxidation reactions at the alloy surface (e.g. M → Mn+ + ne‒). These electrons are consumed in the reduction of solution species (e.g. H+ + e‒ → ½ H2) leading to gaseous evolution and deposition of solid species at the alloy surface. At this step, a higher pH in the vicinity of alloy surface causes decomposition of the passivating ion, which in turn leads to initiation and growth of the coating layer. Interfacial properties, such as adhesion and anti-corrosion behavior, are dependent on the chemical bonding, thermodynamic stability, uniformity, and continuity of this coating layer along the metal surface. This presentation will show our recent studies on the effect of various additives in the conversion coating solutions using electrochemical tools, thermodynamic stability measurements, and electron microscopic analysis.
Highly UV and Corrosion - Resistant Poly(vinylidene fluoride)‐Co‐Hexafluoropropylene - Carbon Nanotubes Superhydrophobic Nanocomposite Coating for C-Steel
Authors: Bahgat Radwan A. , El Basiony N M , Abdullah Aboubakr Moustafa
Published: February 2020

A robust superhydrophobic nanocomposite coating (PVDFHFP-CNTs) of poly(vinylidene fluoride)‐co‐hexafluoropropylene (PVDFHFP) and carbon nanotubes (CNTs) was fabricated on carbon steel using a two-step process: electrospinning and spray coating. The wettability properties of the prepared coating were inspected by measuring the water contact angle (WCA). Before the addition of CNTs, the WCA and the sliding angle (SA) of the PVDFHFP were 150°±3 and 2°±3, respectively while after the addition of CNTs, their values increased to 155°±2 and 3°±2, respectively. The wettability of the as-prepared coatings was also inspected after exposure to UV radiation with a light power of 0.89 W m-2 for 41 cycles according to ASTM standard D4587 – 11 (general metal coatings Standard) whereas each cycle includes 8 h exposure to UV illumination at 60 °C, and condensation for 4 h at 50 °C. It was found that the measured WCA and water contact water angle hysteresis (WCAH) for PVDFHFP-CNTs nanocomposite 152° ± 2 and 6° ± 2 compared to 147° ± 2 and 17° ± 3 of pure PVDFHFP, respectively. The morphology of the superhydrophobic coating was explored. It shows a beaded-like fiber structure. Spectra elements of the prepared coatings were obtained using the Fourier transform infrared instrument (FTIR). The surface roughness of the fabricated super water-repellent coatings were measured using atomic force microscope (AFM). The electrochemical behavior of superhydrophobic coating was evaluated by electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl before and after exposure to UV radiation. The outcomes showed the high corrosion resistance of PVDFHFP-CNTs compared to the neat PVDFHFP coating in presence and absence of UV.
(Corrosion Division H. H. Uhlig Award) Shedding Light on Corrosion
Authors: Davenport Alison J
Published: February 2020

The shape and ultimate stability of corrosion sites is highly sensitive to the competition between active dissolution and passivation. In situ methods, especially those involving synchrotron X-rays, are key to understanding both passivation and dissolution processes. The growth of passive oxide films can be a very rapid solid state process, often with good epitaxy between the metal and the oxide. The rate of dissolution is highly sensitive to the local solution chemistry as well as the interfacial potential, and may be affected by the formation of salt layers. X-ray imaging, scattering and spectroscopy can shed light on these processes, and their interdependence during the development of localised corrosion sites.
(Invited) Microstructure Controlled Ni‐Rich NCM Cathode Material By Microscale Compositional Partition for Li-Ion Batteries
Authors: Sun Yang-Kook
Published: February 2020

A multi‐compositional particulate Li[Ni0.9Co0.05Mn0.05]O2 cathode in which Li[Ni0.94Co0.038Mn0.022]O2 at the particle center is encapsulated by a 1.5‐μm‐thick concentration gradient (CG) shell with the outermost surface composition Li[Ni0.841Co0.077Mn0.082]O2 is synthesized using a differential coprecipitation process. The microscale compositional partitioning at the particle level combined with the radial texturing of the refined primary particles in the CG shell layer protracts the detrimental H2 → H3 phase transition, which normally occurs abruptly in Ni‐enriched Li[NixCoyMnz]O2 (NCM) cathodes in the deeply charged state giving rise to a sharp change in the unit cell dimensions. This protraction, which is confirmed by in‐situ X‐ray diffraction and transmission electron microscopy, allows effective dissipation of the internal strain generated upon the H2 → H3 phase transition, markedly improving cycling performance and thermochemical stability as compared to those of the conventional single‐composition Li[Ni0.9Co0.05Mn0.05]O2 cathode. The compositionally partitioned cathode delivers a discharge capacity of 229 mAh g‐
1 and exhibits capacity retentions of 92% after 100 cycles in a coin‐type half cell (cf. 85% for the conventional cathode) and 88% after 1,000 cycles in a pouch‐type full cell (cf. 68% for the conventional cathode). Thus, the proposed cathode material provides an opportunity for the rational design and development of a wide range of multi‐functional cathodes, especially for Ni‐rich NCM cathodes, by compositionally partitioning the cathode particles and thus optimizing the microstructural response to the internal strain produced in the deeply charged state.
(Invited) Promises and Limitations of Fluoride in Next-Generation Batteries: From New Reactions to New Interfaces
Authors: Gallant Betar M.
Published: February 2020

Fluoride-containing additives, electrolytes, solid electrolyte interphases (SEI), and fluorinated materials represent a recurring motif in many proposed next-generation battery chemistries. Fluoride-enrichment at the surface of metallic anodes, such as Li, has been suggested to impart favorable stabilization of the SEI, permitting empirically enhanced round-trip efficiency and cycle life by mitigating dendrite formation. Meanwhile, fluorinated materials such as oxyfluoride intercalation cathodes, fluorinated carbons in primary battery cathodes, and metal fluoride conversion cathodes represent distinct approaches to tailor the behavior of bulk materials. In spite of this promise, precisely manipulating fluoride-based materials and reaction mechanisms remains challenging. In this talk, I describe our group’s exploration of several applications where fluoride-forming reactions can be tailored and harnessed for application in primary and secondary batteries. First, I describe our efforts to develop high-energy density primary batteries based on the electrochemical reduction of fluorinated gases. We show that fundamental knowledge and the experimental framework developed in the field of Li-oxygen batteries in recent years can be successfully translated to the development of new gas-to-solid conversion reactions with high energy densities. Molecular transformation mechanisms occurring during the discharge reactions, which involve atypically high electron transfer numbers (2<n<8), will be presented, and future strategies to improve power density of gas-based conversion systems will be discussed. Then, we shift gears to focus on how fluorinated reactions can be harnessed to modify metal interfaces. We discuss our findings on the reactivity of fluorinated gases with Li surfaces in the development of so-called “artificial SEI” layers on Li, and critically examine the role of LiF in imparting stability to modified interfaces. Finally, we highlight future challenges and opportunities in the modification of cathode materials enriched with fluoride derived from our gas-based reaction architecture.
(Invited) Na-Ion Batteries: Challenges and Opportunities
Authors: Rojo Teofilo
Published: February 2020

With the ever-increasing demands of modern societies, energy generation, storage, and distribution are becoming increasingly important research fields. Currently, one of the most promising areas of research and development is Sodium ion Battery (SIB) technology, which has a range of potential applications but remains particularly suited for use in stationary systems. [1-5].

Here we will discuss SIB systems in terms of what may be considered its three most significant components: anodes, electrolytes, and cathodes. SIB anodes are mainly based on hard carbon materials, due to their attractive combination of low cost and high energy density. However, there has also been interest in other systems, such as intermetallic alloying materials and metal oxides, as well as exploiting specific electrolyte co-solvation effects so as to enable the use of graphite. In general, the SIB research community uses organic electrolytes which are analogous to already existing Lithium ion batteries (LIB). However, recently there has been growing interest in developing new electrolytes which are specifically tailored for use in SIBs, such as optimized liquid and solid electrolytes. At the present time, cathodes are one of the most explored SIB components - with a plethora of options to choose from, including Prussian blue and organic materials. However, the most promising are polyanionic and layered materials, with their good combinations of electrochemical performance, low cost, stability and available constituents. Although interest in SIB technology has only relatively new, when compared to LIBs, it has been already developed at the prototyping level.

A general overview of the most interesting electrode and electrolyte materials for Na-ion batteries paying special attention to those related to the current prototypes will be presented. By examining this topic in detail, it will be shown that there exists a strong drive to exploit this technology and that there are a wide range of opportunities to develop new and improved SIB technologies.

References:

[1] V. Palomares, T.Rojo et al., Energy Environ. Sci., 2012, 5, 5884.

[2] M. Á., Muñoz-Márquez, T.Rojo et al., Adv. Energy Mater., 2017, 1700463.

[3] N. Ortiz-Vitoriano, T.Rojo et al., Energy Environ. Sci., 2017, 10, 1051.

[4] D. Saurel, T.Rojo et al., Adv. Energy Mater., (2018,1703268).

[5] T.Rojo et al., Adv. Energy Mater., (2018,8,1800880).
(IBA Early Career Award) Challenges and Opportunities for Interphased Ca Metal Anode Batteries
Authors: Ponrouch Alexandre
Published: February 2020

Various metals have been used as battery anodes in electrochemical cells ever since the birth of the batteries with Volta’s pile and in the first commercialized primary (Zn/MnO2, Leclanché 1866) and secondary (Pb/acid, Planté 1859) batteries. Li-MoS2 cells, employing Li metal anodes, with specific energies two to three times higher than both Ni/Cd and Pb/acid cells, were withdrawn from the market due to safety issues related to dendrites growth. Instead, electrodeposition of Mg and Ca appears to be less prone to dendrite formation.[1,2] Pioneering work by Aurbach et al. in the early 1990’s showed a surface-film controlled electrochemical behavior of Ca and Mg metal anodes in electrolytes with conventional organic solvents.[3,4] The lack of metal plating was attributed to the poor divalent cation migration through the passivation layer. Nevertheless, recent demonstration of Ca and Mg plating and stripping in the presence of a passivation layer or an artificial interphase [2,5,6] has paved the way for assessment of new electrolyte formulations with high resilience towards oxidation. However, several challenges remain to be tackled for the development of Ca based batteries.[7] Among these, the need for reliable electrochemical test protocols, mass transport limitations and high desolvation energies (due to strong cation-solvent and cation–anion interactions) are implied.[8] Here, the reliability of electrochemical set-ups involving multivalent chemistries is discussed, and a systematic investigation on the impact of the electrolyte formulation on the cation solvation structure and transport is presented. Finally, a systematic characterization of the SEI formed on the Ca metal anode in various electrolyte formulations using complementary techniques allowed for the identification of the most suitable SEI compounds in terms of divalent cation mobility.

Reference
s
:

[1] M. Matsui, J. Power Sources, 196 (2011) 7048.

[2]. A. Ponrouch, C. Frontera, F. Bardé, M.R. Palacín, Nat. Mater., 15 (2016) 169.

[3] D. Aurbach, R. Skaletsky, Y. Gofer, J. Electrochem. Soc.138 (1991) 3536.

[4] Z. Lu, A. Schechter, M. Moshkovich, D. Aurbach, J. Electroanal. Chem. 466 (1999) 203.

[5] D. Wang, X. Gao, Y. Chen, L. Jin, C. Kuss, P. G. Bruce, Nat. Mater. 17 (2018) 16.

[6] S.-B. Son, T. Gao, S. P. Harvey, K. X. Steirer, A. Stokes, A. Norman, C. Wang, A. Cresce, K. Xu, C. Ban, Nat. Chem. 10 (2018) 532.

[7] A. Ponrouch, M.R. Palacín, Current Opinion in Electrochemistry 2018,doi.org/10.1016/j.coelec.2018.02.001.

[8] D. S. Tchitchekova, D. Monti, P. Johansson, F. Bardé, A. Randon-Vitanova, M. R. Palacı́n, A. Ponrouch, J. Electrochem. Soc., 164 (2017) A1384.

Figure 1: Scheme of a Ca metal anode-based battery

with the main problems/ requirements outlined.[7]

Figure 1
(Invited) Tracing Reactivity through Outgassing in Ni-Rich and Li-Rich Li-Ion Cathode Materials
Authors: McCloskey Bryan D.
Published: February 2020

Outgassing of active materials in Li-ion batteries provides a route to quantitatively study degradation processes that occur during cycling. In particular, we are primarily interested in quantifying the individual and coupled decomposition/transformations of the cathode – a lithiated transition metal oxide (TMO) – and the electrolyte – most commonly carbonate blends (ethylene carbonate, diethyl carbonate, etc.) with lithium hexafluorophosphate (LiPF6) as the salt. Previous observations of high-voltage instabilities include TMO surface reconstruction, transition metal dissolution, electrolyte decomposition, and formation of surface species. However, this picture is still incomplete, with the dependence on electrolyte and TMO composition not yet fully understood. We will present results in which isotopic labeling of 18O in Ni-rich and Li/Mn-rich NMCs is combined with quantitative gas evolution analysis to show that residual solid lithium carbonate (Li2CO3) on the surface of TMOs has a direct impact on electrolyte and electrode degradation. In particular, oxygen release from the TMO lattice is related to the amount of Li2CO3 present in the cathodes. Our results suggest that the role of impurities on interfacial reactivity in batteries is critically important and should be a key parameter considered in similar future studies.
Semi-Solid Li-S Battery Electrolytes
Authors: Navarro-Suárez Adriana , Johansson Patrik
Published: February 2020

The urge for electrochemical energy storage devices with high gravimetric and volumetric energy density is imminent and the lithium−sulfur (Li-S) battery has been poised as a major next generation battery concept candidate. While it has a (very) high theoretical energy density, low cost and non-toxicity of starting materials,[1] its practical application has been hampered by several obstacles; the active material(s) elemental sulfur (S8) and lithium sulfide (Li2S) are both electronic insulators, polysulfides dissolve into the electrolyte and diffuse between the cathode and anode –generating an active material loss, there are dendrites formed at the lithium metal anode, etc.[2,3]

To address (some of) these problems, the solubility properties of the electrolyte are of utmost importance [4] and here we use semi-solid electrolytes to try to hinder the dissolution of sulfur and possibly also mitigate the creation of lithium dendrites. These systems are composed of a deep eutectic electrolyte (DEE), LiTFSI and/or LiFSI based, confined within a porous silica framework – creating an eutectogel.[5] We here report on the initially assessed physico-chemical properties, basic electrochemical properties such as ion conductivity (Figure 1), before progressing to feasibility tests in Li-S battery cells.

This work was funded by “Batterifondsprogrammet” of the Swedish Energy Agency.

Figure 1. Arrhenius plot of a DEE and a DEE confined in a SiO2 framework.

Reference
s

[1] Q. Pang, X. Liang, C.Y. Kwok, L.F. Nazar, Nat. Energy 1 (2016) 16132.

[2] X. Judez, H. Zhang, C. Li, G.G. Eshetu, J.A. González-Marcos, M. Armand, L.M. Rodriguez-Martinez, J. Electrochem. Soc. 165 (2018) A6008–A6016.

[3] J. Scheers, S. Fantini, P. Johansson, J. Power Sources 255 (2014) 204–218.

[4] S. Drvarič Talian, S. Jeschke, A. Vizintin, K. Pirnat, I. Arčon, G. Aquilanti, P. Johansson, R. Dominko, Chem. Mater. 29 (2017) 10037–10044.

[5] B. Joos, T. Vranken, W. Marchal, M. Safari, M.K. Van Bael, A.T. Hardy, Chem. Mater. 30 (2018) 655–662.

Figure 1
Investigation of Molten Salt Chemical Cell Using Nd Magnet Scraps and Gas Electrodes in Molten Chlorides
Authors: Konishi Hirokazu , Koizumi Yuichiro
Published: February 2020

Here we study the molten salt chemical cell using Nd magnet scraps and Cl2 or O2 gas electrodes in order to achieve new rare earth recycle process. The anodic polarization of Nd magnet scraps and cathodic polarization of O2 gas electrodes were investigated in molten LiCl-KCl systems at 723 K. The anodic polarization was carried out by potentiostatic electrolysis of Nd magnet scraps electrode from 0.69-2.39 V(vs. Li+/Li) at every 0.050 V interval. The large anodic current was observed at 1.80-2.00 V due to anodic reaction of dissolution of rare earth elements. On the other hand, the cathodic polarization was carried out by potentiostatic electrolysis of O2 gas electrode using porous Ni from 1.20-2.30 V at every 0.10 V interval in a molten LiCl-KCl added Li2O(0.50 mol%) system. The large cathodic current was observed from 1.40-1.90 V due to cathodic reaction from O2 to O2-.
A Stable 3 V All-Solid-State Battery Based on a Closo-Borate Electrolyte
Authors: Duchêne Léo , Kühnel Ruben-Simon , Asakura Ryo , Payandeh Seyedhosein , Remhof Arndt , Battaglia Corsin
Published: February 2020

Closo-borates represent a promising but yet under-explored alternative class of electrolytes for all-solid-state batteries. We recently reported ionic conductivities of 1 mS/cm and an electrochemical stability window of 3 V at room temperature for Na4(B12H12)(B10H10).[1] The mixed-anion configuration stabilizes the ion-conducting high-temperature phase at room temperature.

We further demonstrated stable cycling for a 3V class all-solid-state battery based on this electrolyte consisting of a sodium metal anode and a NaCrO2 cathode.[2] The cathode composite can be assembled by simple cold pressing, but cycling performance is enhanced through a preliminary solvent-based impregnation step of the cathode particles by a thin electrolyte coating. This coating guarantees intimate contact between cathode particles and electrolyte resulting in reversible and stable cycling with a capacity of 85 mAh/g at C/20 and 80 mAh/g at C/5 with more than 90% capacity retention after 20 cycles at C/20 and 85% after 250 cycles at C/5. We also investigated the effect of cycling outside the electrochemical stability window and observed that electrolyte decomposition leads to faster though not critical capacity fading.

We will further present routes to translate these results to lithium analogues and our efforts to establish low-cost synthesis routes for these non-toxic materials. Our results demonstrate that owing to their physical properties and processability, closo-borate-based electrolytes could play a significant role in the development of a competitive all-solid-state battery technology.

[1] L. Duchêne, R.-S. Kühnel, D. Rentsch, A. Remhof, H. Hagemann, C. Battaglia, Chem. Comm. 53, 4195 (2017)

[2] L. Duchêne, R.-S. Kühnel, E. Stilp, E. Cuervo Reyes, A. Remhof, H. Hagemann, C. Battaglia, Energy & Environmental Science 10, 2609 (2017)

Figure 1
Metrics of Hybrid Polymer/Ceramic Electrolyte for Solid-State Batteries Powering Electric Vehicles
Authors: Mao Chengyu , Kim Seung Wan , Liu Ying
Published: February 2020

All solid-state batteries have become the focus of next-generation Li-ion battery research and development to meet the ever-growing demands on safe and high-energy-density storage systems. Replacing conventional electrolytes with solids mitigates issues associated with flammable organic liquid and makes safer battery systems. Solid electrolytes which are stable against lithium and resistant to Li dendrite penetration could enable the use of metallic lithium anode, offering a promising pathway to deliver lithium-ion cells with energy densities that significantly exceeds 350 Wh/kg. While each main class of solid electrolytes has their intrinsic challenges, integrating different group of solid electrolytes such as polymers and ceramics has the potential of bringing their individual advantages together and overcoming their drawbacks. In this study, we fabricated a group of hybrid polymer/ceramic electrolytes made from commercially available materials. Their ionic conductivity, electrochemical stability, interfacial stability towards metallic lithium, thermal property, processability and mechanical strength were systematically investigated. Finally, we develop a metrics to screen these hybrid solid electrolytes and identify promising candidates which are most relevant to electric vehicles (EV) applications. Our study illustrates the importance of component integration in developing high-performance solid-state electrolyte. This work serves as a guide to select the appropriate solid electrolytes that can power future electric vehicles.