bluuebunny/crossref_metadata_2025 huggingface dataset:
Advantages of ZrO2 Composite Protection Coating on Lithium Metal Anode in Lithium Metal Battery
Authors: Jang Eun Kwang , Ahn Jinhyeok , Yoon Sukeun , Cho Kuk Young
Published: February 2020

Lithium metal anode was regarded as holy grail due to its high theoretical capacity (3860 mAh /g) and lowest electrochemical potentials (–3.04 V vs SHE). However, the dendrite formation induces safety hazard and decomposition of liquid electrolyte, resulting in low Coulombic efficiency and short cycle life. Recently, many studies have studied approaches to suppress dendrite growth by stable SEI layer, optimization of solvents, salts, electrolyte additives, and protection layer. The protection layer was well known method to prevent dendrite growth and improve cycle stability. Here we fabricate composite protection coating on lithium metal anode to prevent dendrite formation and prevent salt dissociation. This protection layer has high ionic conductivity and superior mechanical properties. The protection layer successfully suppresses dendrite formation and improves coulombic efficiency. In this study we show potential of achieving highly safe lithium metal anode.
Zero Emission Buses: State of the Industry and Deployment Best Practices
Authors: Raudebaugh Dan
Published: February 2020

Like most US transportation sectors, public transit is transitioning to zero-emission vehicles. This presentation will provide a breakdown of the state of the zero-emission bus (ZEB) industry and share best practices for deploying zero-emission buses. The Center for Transportation and the Environment (CTE) has collected US ZEB cumulative awards and sales data as well as product offerings available from bus manufacturers in the ZEB space. The results show a ten-fold increase in ZEB annual awards and sales from 2009 to 2017, with battery electric buses now making up about 6% of annual transit bus purchases. Product offerings by battery electric bus manufacturers show an increase in battery capacity and nominal range as newer models are unveiled, with vendor reported ranges averaging 200 miles. ZEBs include both battery electric and fuel cell electric technologies, with fuel cell electric buses offering ranges and refueling operations more similar to conventional bus technologies. Thus, best practices for deployment of a battery electric bus revolve around determination of expected real range in a given application and planning route service and charging operations to fit this range. Best practices for both ZEB technologies include evaluating infrastructure costs at scale. On-board energy storage capacity and nominal ranges for all ZEBs are expected to increase and improve over time. CTE is presently working with more than 60 transit agencies purchasing and deploying ZEBs.
(Invited) Molten Salt Synthesis of Lithium Conducting Garnets for More Scalable Solid-State Batteries
Authors: Weller Jon Mark , Chan Candace K.
Published: February 2020

Solid-state lithium-ion batteries (SSLIBs) can simultaneously improve both energy density and safety over current state-of-the-art lithium-ion batteries (LIBs). These critical advantages are expected to enable next generation battery-based energy storage for both commercial applications such as consumer devices and transportation and greater utilization of renewable energy technologies. The key component to SSLIBs is the solid-electrolyte, ideally allowing fast ion conduction, possessing electrochemical stability with metallic lithium to enable higher energy density, and exhibiting chemical stability under ambient conditions. Lithium conducting garnets, in particular doped lithium lanthanum zirconate (LLZO) possess all of these advantageous characteristics. While lithium garnets have demonstrated exceptional properties under laboratory conditions, only a few groups have demonstrated a robust, scalable process to integrate them into SSLIBs. Some of the main challenges to incorporating garnets such as LLZO are the relatively high processing temperatures required and brittle nature of devices based on these sintered polycrystalline ceramics. Processing schemes amenable to roll-to-roll type processing such as tape-casting have been demonstrated, but generally require very fine powders to produce thin electrolyte membranes and subsequently low cell resistance. However, lithium garnets are most commonly synthesized via solid-state reactions (SSR), generally requiring high temperatures (> 900 °C), long reaction times (often in excess of 8 h), and concomitant high energy cost. Further, the resultant particle sizes of LLZO synthesized via SSR are relatively large, and fine powders are only obtained after further processing via high energy milling. Molten salt synthesis (MSS) has recently been demonstrated as an alternative strategy to obtain phase-pure crystalline LLZO, with the added benefit of generally shorter reaction times (4 h or less), lower temperatures, and in some cases inherently submicron particle sizes, while maintaining expected high ionic conductivity. Design principles for formation of doped and co-doped LLZO are discussed, wherein salt and reagent composition have direct effects on the formation temperature, particle size, particle size distribution, and electrochemical performance of the as-synthesized material. By engineering inherently fine LLZO powders, a more direct route to practical processing methods such as tape-casting becomes accessible. As such, MSS may prove to be a crucial method to allow LLZO and SSLIBs based on it to transition to a scalable solution for safer, more efficient battery-based energy storage.
Cathode Interfacial Resistance in Lithium-Sulfur Batteries Under Lean Electrolyte Condition
Authors: Zhao Yifan , Guo Juchen
Published: February 2020

Lithium Sulfur battery is supposed to be one of the most promising candidates in next generation rechargeable batteries. Owing to the high theoretical specific capacity (~1675 mAh/g) and abundance of sulfur, lithium-sulfur battery can achieve high energy density with relatively low cost. However, the practical energy density is much smaller than the theoretical value. The operation of Li-S batteries under lean electrolyte condition was revealed by investigating Li-S pouch cell under different electrolyte/sulfur ratio. The cathode interfacial resistance was figured out in testing Electrochemical Impedance Spectroscopy (EIS) during discharging for different E/S ratio. The electrolyte resistance, interfacial resistance as well as the charge transfer resistance were keeping changing in same trend for different E/S ratio. The changing was observed in both DOL/DME and DMSO electrolytes for all E/S ratios we tested. Such resistance behaviors were also confirmed by enforced Galvanostatic Intermittent Titration Technique (GITT). By applying enforced GITT onto the lean electrolyte cell, it can even get as high specific capacity as flood electrolyte cells did. We propose that the cathode interfacial resistance can be one of the reasons which is challenging the Li-S battery to achieve its theoretical specific capacity under lean electrolyte condition. Such mechanistic understanding of the Li-S battery under lean electrolyte condition can provide guidance in developing high energy density Li-S battery.
Carbon Nanotubes-Silica Nano Composite Synthesis By CVD Method: A Promising Composite Material Development for Lithium Ion Battery Application
Authors: Ali Zulfiqar
Published: February 2020

Carbon-silicon material for lithium ion battery has recently been realized is promising material due to excellent lithiation property of silicon coupled with good carbon nanotube electrical conductivity in nanocomposite. In this work such material synthesis technique is described by first employing nickel silica alcogel as catalyst followed by direct chemical vapor deposition of prepared catalyst to result into nickel silicon carbon nanotubes nanocomposite. later, nickel metal which formed in-situ during CVD is successfully removed by treatment with concentrated hydrochloric acid. Thus, we have just synthesized this unique material which is promising and may be used as suitable anode material for lithium ion battery and lithium ion battery tests such as charge discharge, energy density, power density etc. will be performed and results will be presented by the time of conference.

The graphitic carbon deposition was confirmed by X-ray diffraction (XRD) studies and field emission secondary electron microscopic (FE-SEM) images reveled the tube-like and nest type morphologies which are characteristics of MWCNTs in silica matrix. The effect of nickel content and temperature on carbon nanotubes contents in silica matrix were also studied. The carbon content in the samples was estimated with CHNS elemental analyzer. The average tube diameter of material synthesized was in the range of 30-60 nm. Moreover, it was found that 12M hydrochloric acid concentration was required to completely remove nickel content from synthesized carbon nanotubes nanocomposite which was confirmed by XRD studies.

Figure 1
(Invited) Atomic-Scale Insights into Solid Electrolyte Materials: Defects, Conduction & Interfaces
Authors: Islam M. Saiful
Published: February 2020

Major advances in solid-state lithium batteries require the discovery and characterization of solid electrolyte materials. It is clear that a complete understanding of such materials requires greater fundamental knowledge of their underlying structural, ion transport and interface properties on the atomic- and nano-scales. For example, grain boundary effects on Li-ion transport are not fully understood. This talk will highlight recent studies [1-3] in two related areas: the influence of grain boundaries on Li-ion conduction in the Li-rich anti-perovskite Li3OCl and the particle morphologies and lithium segregation to surfaces of the garnet Li7La3Zr2O12. A combination of advanced materials modelling techniques has helped us gain new insights into these complex materials, which are valuable in developing strategies to optimize their electrolyte properties.

[1] J.A.Dawson et al., J. Am. Chem. Soc., 140, 362 (2018).

[2] P. Canepa et al, Chem. Mater., 30, 3019 (2018)

[3] Y. Deng et al., ACS Appl. Mater. Interfaces
, 9, 7050 (2017); Y. Deng et al, Chem. Mater., 30 (2018)
Ni Ions Catalyzation Effects on Cathode Electrolyte Interphase for High Performance and High Safety Lithium Ion Battery
Authors: Wang Fu-Ming
Published: February 2020

In January 2017, Samsung announced the reason why the Note 7 explodes and losses of more than 5 billion US dollar. According to their explanations, it was caused by the internal short circuit problem in the lithium ion battery. Currently, there is no effectively solution for eliminating the internal short circuit problem owing to the sudden accident.

In this research, a new technology has been developed, which can be used to terminate the thermal runaway and promise the safety performance of lithium ion battery. High voltage Li-excess and Ni-rich layer-type cathode material is employed and combined with this safety electrode additive for investigation. In terms of the results, the new technology LIVING@additive significantly enhances the cycle performance at 60oC and high voltage. In addition, the following figures illustrated that the battery containing LIVING@technology is stable and passed the nail penetration test. On the other hand, the battery without LIVING@ cannot be used when the short problem is taking place. The LIVING@contains self-polymerized hyper branch structure in order to insulate the directly contact between anode and cathode. This electrode additive not only provides high thermal stability on electrochemical reaction, but the columbic efficiency of charge-discharge is also enhanced.
Preventing Gas Formation in Dual Carbon Battery By Using Mixed Supporting Salt of LiPF6-LiBF4
Authors: Ishihara Tatsumi , Inda Keisuke , Kurihara Takuya
Published: February 2020

Rechargeable battery with large energy capacity as well as superior rate property is strongly required for electric vehicle and hybrid vehicle. Dual carbon battery which is expected as a post Li ion battery with superior rate property, is based on intercalation of anion and cation into graphitic carbon and advantages on cycle stability and high discharge potential (>4V), however, low coulomb efficiency by gas formation is the most serious issue for this battery. In this study, gas formation mechanism was analyzed based on LiPF6/ethylene carbonate (EC) and diethylene carbonate (DMC).

Mass analysis of the formed gas suggests that the main species in gas was C2H6, C2H4, CO, and CH4 and the formation of these gas may be assigned to the electrochemical decomposition of EC during charge step. In the initial charge step, gas formation was observed from anode side at initial period and from cathode side at final period. Therefore gas formation from anode side could be assigned to the formation of SEI and that from cathode side could be oxidation of EC in electrolyte. Therefore, by using simple DMC electrolyte, amount of gas formation can be decreased. Among the examined electrolyte, gas formation amount became smallest when DMC was used for electrolyte. In addition, it was found that amount of gas formation was significantly suppressed by using LiBF4-DMC electrolyte, however, discharge capacity became smaller (ca. 40mAh/g). Therefore, mixing LiPF6 with LiBF4 in DEC shows the reasonable large discharge capacity (ca. 87 mAh/g) and the amount of gas was also suppressed. The optimized ratio for mixing was LiPF6:LiBF4=3:1 and gas amount formed became smaller by an order of magnitude. Although low coulomb efficiency was observed at the fist cycle, high coulomb efficiency was sustained over 300 cycles examined.
Preparation and Characterization of Polyethylene Oxide and Polycarbonate Based Composite Cathodes
Authors: Tessmer Britta , Buchheit Annika , Wiemhöfer Hans-Dieter
Published: February 2020

In the last years, the attention on all solid-state batteries increased due to safety reasons. In current lithium ion batteries, organic solvents are used which can penetrate porous cathodes to ensure a good ion conductive contact with the active material. The advantage of these solvents is the good penetration in the porous cathodes. Major drawbacks are possible leakage and high flammability of the liquid electrolyte. Due to this reason, one approach is to replace the liquid by non-volatile solid electrolytes. A change in the state of aggregation causes some adjustments relative to the cathode. Solid electrolytes, which can be ceramics, glasses or polymers, are not able to penetrate the cathode as a liquid electrolyte can do. Therefore, the electrode has to consist of an additional lithium ion conductive compound. Possible polymeric materials are polyethylene oxide (PEO), polyethylene- and polypropylene carbonate (PEC/PPC) in combination with a lithium salt [1-3], for example lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).

The choice of the materials for the electrolyte was done by the means of conductivity, transference number of Li+, as well as processability and availability. As the starting point and for comparison, the well investigated system PEO/ LiTFSI [4] was used. In the second part, PEO was replaced by PEC or PPC. To optimize these electrolyte systems, different compositions were prepared using the hot press method and characterized regarding the conductivity and electrochemical stability.

The electrolytes with the highest conductivity were used to prepare composite cathodes using carbon black as electronically conducting additive as well as lithium iron phosphate (LFP) as active cathode material. The aim is to produce stable composite cathodes containing the solid polymeric electrolyte, active LFP particles and carbon black, which perform in a sufficient way. Also additionally additives, e.g. plasticizers, can be used to improve the performance of the whole cathode. Here, the hot press method was used again to obtain compact composites. The subsequent characterization was done with electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Also cycling tests were performed finally, which show moderate capacities. Further improvements are planned to achieve a higher capacity.

Acknowledgements

The authors acknowledge funding by the German Federal Ministry for Economic Affairs and Energy (BMWi) within the project FesKaBat (03ET6092E).

References

[1] P. Knauth, Solid State Ionics, 180, 911-916 (2009).

[2] W. Gorecki, M. Jeannin, E. Belorizky, C. Roux, M. Armand, J. Phys.: Condens. Matter, 7, 6823-6932 (1995).

[3] Z.-J. He, L.-Z. Fan, Rare Met., 37(6), 488-496 (2018).

[4] M. Hiller, M. Joost, H.J. Gores, S. Passerini, H.-D. Wiemhöfer, Electrochim. Acta, 114, 21-29 (2013).
Increased Cycle Stability of Dual Carbon Batteries By Using LiPF6 – LiTFSI Mixed Salt Electrolyte
Authors: Nakamura Kotaro , Akbay Taner , Madrid Jose , Inda Keisuke , Takagaki Atsushi , Ishihara Tatsumi
Published: February 2020

Rechargeable battery with large energy capacity as well as superior rate property is strongly required for electric vehicle and hybrid vehicle. Dual carbon battery which is expected as a post Li ion battery, is based on intercalation of anion and cation into graphitic carbon and advantages on cycle stability and high discharge potential (> 4 V). However, low coulomb efficiency by gas formation is the most serious issue for this battery. In this study, effects of mixing LiPF6-LiTFSI in dimethyl carbonate (DMC) for electrolyte of DCB were studied.

For electrochemical measurements, graphitic carbon of KS6 (TIMCAL) and MAGD (Hitachi Kase) were used for the positive and negative electrode, respectively. For the charge/discharge investigations, a constant current rate of 0.5 mA cm−2 was applied for both charge and discharge steps, and the potential windows of 3.0 V to 5.2 V was used. LiPF6, LiTFSI and DMC of lithium battery grade (Kishida Chemical Co., Ltd., Japan) were used. The LiPF6-LiTFSI/DMC electrolyte was prepared by dissolving LiPF6, LiTFSI (battery grade) in DMC in a dry argon-filled glove box without further purification. Coin type cell was assembled in a glove box filled with a dry argon atmosphere.

It was found that mixing LiPF6 and lithium bis(trifluoro methanesulfonyl)imide (LiTFSI) at 1:1 for a support salt was highly effective for increasing coulomb efficiency and cycle stability. When LiPF6-LiTFSI in DMC was used, the discharge capacity of 90 mAh/g-cathode was sustained over 300 cycles without almost no degradation. Coulomb efficiency higher than 98% was achieved after 10 cycles suggesting a decreased gas formation, and it was also found that corrosion of Al current corrector was prevented by using LiPF6-LiTFSI mixed salt. DFT calculation and NMR measurement suggests that the complex anion of (PF5-TFSI)- and F- was formed resulting in the increased stability of intercalated anion and preventing Al current collector corrosion. It was also suggested that PF5-TFSI anion shows fast diffusivity in graphitic carbon which is in good agreement with superior rate property.
Synthesis and Electrochemical Performances of the High Nickel Content Layer-Structured Cathode Materials for High-Energy Libs
Authors: Kim Hyun-Soo , Lee Seung-Hwan , Lee Seul , Jin Bong-Soo
Published: February 2020

Among the various cathode candidate, layer structured Li(Ni,Co,Mn)O2 (NCM) has been regarded as the most attractive alternative to LIBs owing to relatively modest volume change (LiCoO2), high specific capacity (LiNiO2) and good thermal stability (LiMn2O4). Although Li(Ni1/3Co1/3Mn1/3)O2 has been successfully commercialized as a battery cathode, researches on Ni-rich NCM (LiNixCoyMn1−x−yO2, x > 0.5) have been spotlighted due to its superior capacity (> 200 mAh/g, at 4.6 V vs. Li/Li+) [10]. Therefore, the future of NCM for high energy LIBs strongly depends on Ni-rich NCM materials.

It is reported that crystallinity and morphology, influenced by the sintering temperatures, all play important roles in the electrochemical performances. In this paper, we report the synthesis of LiNi0.91Co0.06Mn0.03O2 cathode materials with different sintering temperatures. Also the relationship between the sintering temperatures and the electrochemical performances is investigated. The sintering temperatures affect a crystallinity and morphology, which play an important role in electrochemical performances of LiNi0.91Co0.06Mn0.03O2. The electrochemical performances have improved with increasing sintering temperatures. The LiNi0.91Co0.06Mn0.03O2 sintered at 720 oC shows remarkably excellent performance: initial discharge capacity: 100 mAh/g, cycle performance: 98 % retention after 100 cycles (at 0.5 C) and rate capability: 88 % (at 2 C). These results indicate that LiNi0.91Co0.06Mn0.03O2 can be regarded as a next generation cathode for high-performance lithium ion batteries.
Influence of Li Content on Structure and Electrochemical Performance of Lithium-Rich Cathode Materials for Lithium-Secondary Batteries
Authors: Chen Yufang , Xu Jing , Zheng Chunman
Published: February 2020

Li- and Mn-rich cathode materials win huge attentions due to their extremely high capacity and unique solid solution composite structure. As a composition contains two or more phase, the compatibility of these phases would be critical points to promise high capacity output. We chose both layered structures which have similar oxygen ion arrangement as framework and distinct cations distribution,
1 to found the xLi2MnO3-yLiNi1/3Co1/3Mn1/3O2 cathode materials. From former researches,
2 Li was always used to adjust the ratio of the layered and monoclinic phase. Thus, in this paper the Li content was changed to adjust the composition of the two contained phase. All the precursors of three samples were synthetized though co-precipitation route, after drying and mixing with lithium, the powders were sintered at 900 oC for 15h to obtain the final products. The XRD (X-ray diffraction) were used to investigate the order of crystal structure of these cathode materials, indicating that the ordering of the layered structure was improved with Li content decreased. The intensity of characteristic peaks for monoclinic phase increases with increasing Li content while the ratio of W
rohom
/W
mono
decrease from 4.1565 through 3.240 and 3.0789 to 2.44, these results combined with the broaden and split more clearly of (006)/(102) and (108)/(110) doublets indicate the formation of more ordered layered structure as more Li sites were occupied. Electrochemical performance was evaluated by galvanostatic mode at C/10 with cutoff voltage of 4.8V. Results show that the more Li in the structure, the lower polarizing voltage can be obtained, otherwise, the much lower first cycle coulombic efficiency accompanied. Rate capability (not shown) can be improved but with much faster capacity fade and voltage decay.

Reference

Chen, Y.; Chen, Z.; Xie, K., Effect of Annealing on the First Cycle Performance and Reversible Capabilities of Lithium-Rich Layered Oxide Cathodes. The Journal of Physical Chemistry C
2014.

Watanabe, S.; Kinoshita, M.; Nakura, K., Capacity fade of LiNi(1−x−y)CoxAlyO2 cathode for lithium-ion batteries during accelerated calendar and cycle life test. I. Comparison analysis between LiNi(1−x−y)CoxAlyO2 and LiCoO2 cathodes in cylindrical lithium-ion cells during long term storage test. J. Power Sources
2014,
247 (0), 412-422.

Figure 1
(Invited) Mitigation of Electrode Swelling of Pure Si Nano-Flake Anode for Advanced Lithium-Ion Batteries
Authors: Inaba Minoru , Haruta Masakazu , Doi Takayuki
Published: February 2020

The poor cyclability of pure Si electrodes is attributed to crack formation and pulverization of Si active material due to a large volume expansion and contraction during charging and discharging, respectively. It is thus important to suppress the physical stress induced by the large volume changes to improve the cyclability of Si electrodes. We designed a Si powder with a flake shape (Si LeafPowder®, Si-LP, OIKE & Co., LTD.) with 100 nm in thickness and 3-5 mm in lateral dimension, and have reported that Si-LP electrodes have a high initial discharge capacity (ca. 2,500 mAh g-1) and good cycleability (Fig. 1) [1]. Another serious problem of Si anode is a swelling of the electrode owing to irreversible microstructural changes of Si nano-flakes upon cycling (Fig. 2) [2]. The Si-LP sheets in a composite electrode were substantially deformed during alloying/de-alloying cycling and formed the multi-folded layered structure on repeated cycling. Furthermore, many voids, which could accommodate volume changes of Si, were formed on repeated cycling. The multi-folded layered structure with many voids enabled the stable battery operation of the Si-LP electrodes.

Though good cycleability is obtained, the observed electrode swelling during cycling (Fig. 3) is not affordable for practical use. In this talk, we present some mitigation methods developed for suppression of electrode swelling of Si-LP anode and Si thin film anode, including the effects of additives (VC, FEC in Fig.4) [2], the effects of particle size, the effects of oxide content [3], the effects of pre-film formation [4], the effects of artificial SEI film [5], etc.

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

References

[1] M. Saito, et al., J. Power Sources, 196(16), 6637–6643 (2011). Doi:10.1016/j.jpowsour.2011.02.042

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

[3] M. Haruta, et al, J. Electrochem. Soc., accepted for publication.

[4] M. Haruta, et al., J. Electrochem. Soc., 165 (9) A1874-A1879 (2018). DOI: 10.1149/2.1291809jes

[5] M. Haruta, et al., Nanoscale, 10(36), 17257-17264 (2018). DOI: 10.1039/c8nr05354e

Figure 1
(Invited) Heteronanomat Frameworks As a New Electrode Design for Advanced Lithium-Ion Batteries
Authors: Lee Sang-Young
Published: February 2020

Forthcoming smart energy era is in strong pursuit of advanced power sources with reliable electrochemical performances. To date, most research approaches have still relied on traditional synthetic materials and stereotyped electrode architecture (i.e., thickness-directional, simple pile-up of electrode active materials/conductive additives/polymeric binders on top of metallic current collectors), which have posed major obstacles to sustainable progress of the energy storage systems. For example, the presence of electrochemically-inert materials such as metallic current collectors and polymer binders exerts negative influence on volumetric/gravimetric capacity of electrodes. Moreover, the monotonous electrode architecture often gives rise to electrode thickness-dependent irregularity of electronic/ionic conduction pathways and also loss of structural integrity upon external deformation stresses. Here, we demonstrate a new class of heteronanomat-structured electrodes based on carbon nanotubes (CNTs), cellulose nanofibrils and electrospun polymeric nanofibers to resolve the long-standing challenges of conventional electrodes described above. This material/structural uniqueness allows the formation of three-dimensional bicontinuous CNT electron networks and electrolyte conduction channels, in addition to improving the mass loading of electrode active materials and also mechanical flexibility. As a result, the heteronanomat electrodes provide unprecedented advances in the electrochemical performance and shape diversity that lie far beyond those achievable with conventional battery electrode architectures. We envision that the heteronanomat-structured electrode strategy holds a great deal of promise as a reliable and versatile platform technology to open a new route toward advanced lithium-ion batteries.

References

Sang-Young Lee et al. Adv. Energy Mater. 2017, 1701099.

Sang-Young Lee et al. Adv. Funct. Mater. 2015, 25, 6029.

Sang-Young Lee et al. Adv. Energy Mater. 2015, 5, 1501194.

Figure 1
Flexible Electrochromic Materials
Authors: Kim Haekyoung
Published: February 2020

Electrochromic devices (ECDs) containing electroactive materials can reversibly change their optical absorbance and transmittance according to applied voltage, and this property is utilized in a variety of applications such as reflective displays, antiglare mirrors, smart windows and sensors. Electrochromic devices (EC), which dynamically change colour under applied potential, are widely studied for use in energy-efficient smart windows. To improve the viability of smart windows, many researchers are utilizing nanomaterials, which can provide electrochromic devices with improved coloration efficiencies, faster switching times, longer cycle lives, and potentially reduced costs. The flexible electrochromic films are promising film for applications in automobiles, buildings, etc.

Solution processed tungsten trioxide (WO3)-based electrochromic devices (ECDs) are successfully demonstrated. The thin layers with nanostructured materials of WO3 inks were coated on flexible substrate at room temperature, solution-processed method. In contrast to conventional ECDs based on metal oxides, we controlled the substrate to perform flexible ECDs. The performances of flexible transparent conductive electrodes (TCEs) will be presented. The performances and reliability of with flexible TCE will be presented.
Novel L AGP − PEI Composite Electrolyte
Authors: Lifshitz Moran , Greenbaum (Gutina) Anna , Feldman Yuri , Greenbaum Steve , Golodnitsky Diana
Published: February 2020

Solid electrolytes (SE) have major advantages as an alternative to liquid electrolytes, in terms of reliability, safety, and easy design. SEs are generally defined as electronically insulating solid materials with high mobility and selective transport of charged ionic species within their structure. In general, they can be divided into two main categories: polymeric and inorganic. In this study we focus on the development of a novel composite Li1.5Al0.5Ge1.5(PO4)3 – Polyethyleneimine (LAGP−PEI) polymer-in-ceramic electrolyte, which contains high concentrations of ionic charge carriers with a minimal polymer concentration. Commercial nanoparticles of lithium aluminum germanium phosphate (Li1.5Al0.5Ge1.5(PO4)3, LAGP) were used as a ceramic matrix. Polyethyleneimine (PEI) was tested as a binder and lithium-ion-conducting medium. The combination of nanosize LAGP glass ceramics and PEI polymer was chosen to provide mechanical flexibility with the benefit of the high ionic conductivity of LAGP. The composite electrolytes were prepared by electrophoretic deposition (EPD). TGA, DSC, XRD, ESEM, NMR and EIS tests were used for the characterization of the samples. The dielectric properties of pristine LAGP and LAGP-based quasi-solid electrolytes, containing different concentrations of LiTFSI-based Pyr14 ionic liquid ions, were studied with the use of the BDS 80 (NOVOCONTROL) with automatic temperature control by a QUATRO Cryosystem.

The complex, non-Debye dielectric response of the composite electrolyte has been described in terms of several distributed relaxation processes separated by different frequency and temperature ranges. While at low temperatures, the main contribution is from LAGP, at the middle- and high-temperature regions, the superposition of a few non-Arrhenius processes is observed. 7Li diffusion of the composite electrolyte measured by NMR at 90°C was about 6±2 E-11 m2/s. The correlation of ion-transport phenomena with XRD, DSC and ESEM data will be presented in detail.

Acknowledgements

The research was funded by the Israel Ministry of Science and Technology, grant 53886 and by the Israel Science Foundation (INREP project).
Structure and Dynamics Property of Li-Ion Electrolyte in High Concentration Solution
Authors: Tong Jiahuan , Liang Xiaodong , Solms Nicolas von , Huo Feng , Zhang Suojiang
Published: February 2020

Electrolyte is an indispensable composition in energy storage since the positive and negative electrodes are interconnected by electrolytes that determines the charge transport during the charging/discharging process. Ideal electrolytes should satisfy the following requirements: i.e., excellent electrochemical stability, wide voltage window, high conductivity, environmental friendliness and easy availability with high purity.[
1
,2] In this work, molecular dynamics simulations have been carried out on two organic solvents (dimethyl carbonate, diethyl carbonate) and four imidazolium-based ionic liquids ([Cnmim][X], n=2,4, X=[BF4]- and [TFSI]-) doped with 2 mol/L LiTFSI salt at 298 K and 313 K. Physicochemical properties, including density, viscosity, self-diffusion coefficient and conductivity are investigated. The contribution and influence of independent conductivity type for uncorrelated and correlated ion on the total conductivity are explored. In parallel, the structure of all electrolytes were further analyzed by the radial distribution functions and the ion coordination numbers. Among them, the structures of solute (LiTFSI) were analyzed in details and the effects of different solvents as well as anion and cation of ionic liquids on the interaction of Li+ were explored. The results indicate that the organic solvents restrict the free motion of the ions, reducing the conductivity of the electrolytes, on the contrary, solute is more stable due to the ionic structure of ionic liquids, especially the [C4mim][BF4] with the highest conductivity among the ILs-based electrolytes. More interesting, two conformations of TFSI- (cis and trans) of solute coexist in all electrolytes. Meanwhile, it was found that the effect of Li+ coordination is mainly determined by anion of ionic liquids and the interaction between Li+ and anion of ionic liquids is directly proportional to the length of the side chain of cation for ionic liquids. In this study, the properties and structures of the electrolytes of organic solvents and ionic liquids were compared thoroughly. The advantages of ionic liquid electrolytes are explained in detail and it is helpful to design higher conductive and more stable ionic liquid electrolytes at molecular level.

References

[1] Wang LL, Ye YS, Chen N, Huang YX, Li L, Wu F, Chen RJ. Development and Challenges of Functional Electrolytes for High-Performance Lithium–Sulfur Batteries. Advanced Functional Materials. 2018; 28.

[2] Chen W, Lei TY, Wu CY, Deng M, Gong CH, Hu K, Ma YC, Dai LP, Lv WQ, He WD, Liu XJ, Xiong J. Designing Safe Electrolyte Systems for a High‐Stability Lithium–Sulfur Battery. Advanced Energy Materials. 2018; 8.

Figure 1
Comparison of the Catalytic Activity of Pt(111) with Mononitride Surfaces in Hydrogen Evolution Reaction
Authors: Abghoui Younes , Skulason Egill
Published: February 2020

The outcome of a comprehensive density functional theory (DFT) calculations on the surface of mononitrides in the (100) facets of the rocksalt structure reveals that earlier transition metal nitrides should enable hydrogen evolution reaction (HER) via a Tafel mechanism. To achieve this conclusion, H coverage on the surface was calculated as a function of the applied potential. Activation energies of H2 formation via the Tafel mechanism were also calculated at varying applied potentials. According to these computational results, TaN, HfN, MoN, and ScN are predicted to be capable of catalyzing HER at low overpotentials of −0.09 to −0.34 V versus a reversible hydrogen electrode (RHE)1,2. The interesting point to note here is that the activation energies of the Tafel mechanism on these nitrides were found relatively similar to those reported on Pt(111). Therefore, these materials are interesting for further experimental investigations.

References:

1) Y. Abghoui, E. Skúlason, Hydrogen Evolution Reaction Catalyzed by Transition-Metal Nitrides.J. Phys. Chem. C,
2017
, 121 (43), pp 24036–24045.

2) Y. Abghoui, “Novel electrocatalysts for sustainable ammonia production at ambient conditions”, Ph.D.dissertation, Faculty of Physical Sciences, University of Iceland, 2017, ISBN: 9789935934420.
Differential Electroanalytic Oxidation of Dopamine and Ascorbic Acid at Nickel Oxide Nanoparticles Modified Glassy Carbon Electrode
Authors: Althagafi Zahrah Thamer , Awad Mohamed
Published: February 2020

Abstract:

A simultaneous determination of Dopamine (DA) and ascorbic acid (AA) in their coexistence at nickel oxide nanoparticles modified glassy carbon electrode (nano-NiOx/GCOx) have been achieved. (Nano-NiOx/GCOx) have been prepared by electrodeposition of nickel nanoparticles, and the thus prepared nickel nanoparticles have been subjected to electrochemical oxidation in alkaline medium for the formation of nickel oxide. Modified electrodes have been electrochemically and morphologically characterized. Effect of loading level of nickel was investigated by changing the number of potential cycles for the deposition of nickel nanoparticles, i.e., 1, 2, 5 and 10 potential cycles were used. Also, the experimental and instrumental parameters are optimized. The results have shown that modiﬁed electrode displayed excellent electroanalytic activity towards the oxidation of dopamine (DA) and ascorbic acid (AA) enabling the electrochemical determination of DA and AA using square wave voltammetry in their coexistence.

Key Words: Nanomaterials, Electroanalysis, Electrocatalysis, Nickel Oxide, Glassy Carbon Electrode, Dopamine, Ascorbic Acid
Surface Characterization of Commercial Li-Ion Battery Electrodes Using Scanning Probe Microscopy
Authors: Mitta Saisameera , Stimming Ulrich
Published: February 2020

Electrochemical energy storage is of high importance, as these systems constitute in the development of sustainable energy technologies. Structural changes of a battery electrode upon ion-intercalation were visualized for Li1 and Na2 batteries using STM on the atomic scale in real time. The important properties of a battery is to have a high energy density, high power density, low cost and long cycle life. The state of art choice of one of the cathode materials is NMC for high capacity Li-ion batteries in the electric vehicle applications3,4.However, the structural and interfacial changes of the material during battery operation have not been fully investigated. Hence, it would be interesting to understand the structure of NMC from a fundamental point of view in order to improve its performance.

Within this work, we investigate the commercial cylindrical NMC electrodes with a different degrees of loading using Atomic Force Microscope inside inert gas filled glove box (see Fig). We will also present the atomic resolution of this commercial NMC electrode using Scanning Tunneling Microscope.

Acknowledgements:

This work is partially supported by Faraday Institution and North-East Centre of Energy Materials (EP/R021503/1) funded by EPSRC.

References:

L.Seidl, S.Martens, J. Ma, U.Stimming and O.Schneider, Nanoscale, 2016, 8, 14004.

L. Seidl, N. Bucher, E. Chu, S.Hartung, S. Martens, O. Schneider and U.Stimming, Energy & Environmental Science, 2017, 7.

H. Sun and K. Zhao, The Journal of Physical Chemistry C, 2017, 121, 6002-6010.

S. Bak, E. Hu, Y.Zhou, X.Yu, S.D. Senanayake, S. Cho, K. Kim, K.Y. Chung, X. Q. Yang and K. W. Nam, ACS Applied Materials &Interfaces, 2014, 6, 22594-22601.

Figure 1
In Situ Characterization of Nanostructured Electrode Materials for Energy Conversion and Storage, Using Probe Beam Deflection Techniques
Authors: Barbero Cesar Alfredo , Bruno Mariano M , Coneo Rodriguez Rusbel , Balach Juan , Cotella Nelson Gustavo , Acevedo Diego Fernando
Published: February 2020

Nanostructured conductive materials of large surface area which are important in many areas of energy conversion and storage, including supercapacitors and fuel cells. While electrochemical techniques (e.g. cyclic voltammetry) assess the charge transfer processes at the electrode interface, the ion exchange process could only be inferred. Techniques of ion exchange determination, such as the electrochemical quartz crystal microbalance (EQCM) are of difficult application to porous electrodes since it requires fixing the porous material to the oscillating crystal.

On the other hand, the techniques that monitor ion fluxes outside the electrode surface are able to study the actual ion exchange between a porous electrode and the electrolyte. Among them, Probe Beam Deflection (PBD) is a technique highly suitable to study porous electrodes.[1] The method uses a laser beam travelling parallel to the electrode surface which is refracted by the refractive index gradient associated with the flux of soluble species perpendicular to the electrode, at the center of the laser beam. Since the detection of beam position is optoelectronic, fast (ms) signals can be measured, unlike EQCM, allowing detecting transient phenomena. Since the flux is directly proportional to the surface area (like the current) the ratio of surface area to geometric pathlength (width of the electrode) assures large signal for porous electrodes.

In this report, the study of different electrode materials using Probe Beam Deflection techniques is described. After a qualitative exploration using cyclic deflectometry, a continuous mass transport model is used to quantitatively evaluate the chronodeflectometric response.[2]

First, the study of different porous glassy carbon materials is described. Then, PBD is applied to study mesoporous ordered Pt materials active in direct methanol fuel cells.[3] Finally, thin films of mesoporous oxides decorated with Au nanoparticles,[4] are investigated.

The potential of minimum charge (PMC) can be determined and compared with the value measured by AC Impedance. Besides, transient phenomena like pH changes or effects on the coupled chemical reactions inside the pores can be easily detected. Therefore, a better understanding on the mass transfer in porous electrodes is obtained.

References

1. G.G. Láng and C.A. Barbero, Laser Techniques for the Study of Electrode Processes, Springer, Berlin (2012)

2. G.A. Planes et al, Chem. Commun., 2146-2148, 2005

3. G. Garcia, et al, PCCP, 10, 6677-85, 2008

4. R. Coneo Rodriguez, et al., Sens. & Act. B-Chem., 603 – 612, 2018
Thermo-Electrochemical in-Situ Instrumentation for Smart Energy Storage
Authors: Amietszajew Tazdin , Fleming Joe , Bhagat Rohit
Published: February 2020

Lithium-ion rechargeable cells are widely used as instant power delivery devices. High energy and power densities along with capacity retention over tens of thousands of cycles are highly beneficial compared to alternative technologies. However, recent failure incidents and constant health and safety concerns are slowing down the adoption of this technology and limiting the performance through cautious approach. In order to alleviate these issues, a better understanding of the performance and safety limits and the cells’ internal thermodynamic responses is required. Both the in-situ thermal and electrochemical mechanisms need to be carefully characterised to unlock the full performance without jeopardising safety.

This work focuses on an altogether new in-situ instrumentation methods coupling the use of a quasi-reference electrodes, optical sensing technology and miniature thermistors for supplemental internal and external temperature profiles. This methodology allows for new level of analysis, providing insight into in operando in-situ parameters of a range of cell shapes and formats. Higher reliability, shorter charging times and early fault detection can be achieved with the use of smart instrumented Li-ion cells, enabling significant advances in the battery technology.

Figure 1
Characterizing Carbon Felt Electrodes for Vanadium Redox Flow Batteries Using Differential Electrochemical Mass Spectrometry
Authors: Eifert László , Jusys Zenonas , Behm Rolf Jürgen , Zeis Roswitha
Published: February 2020

Carbon felts are commonly used as electrode materials for vanadium redox flow batteries (VRFBs). Their physical and chemical properties strongly influence the overall cell performance. The degradation of these materials due to parasitic side reactions (carbon corrosion, oxygen and hydrogen evolution) is partially responsible for performance losses of the cell [1].

Differential electrochemical spectrometry (DEMS) has been proven to be suitable for characterizing carbon materials, mainly in the context of fuel cell research [2–4]. Recently, Taylor et al. used DEMS to calculate the Faradaic efficiency of the V3+ reduction reaction on the oxidized edge and basal surfaces of graphite discs in a model study on the activity and stability of the negative electrode in VRFBs [5].

For our experiments, we modified a thin layer flow cell DEMS setup to conduct simultaneous electrochemical and online mass spectrometric measurements on commercial carbon felt electrodes. With this setup, half-cell tests, such as cyclic voltammetry, and coulometry of the redox couples under stopped flow of the electrolyte were performed. We used different potential windows, and two types of electrolytes while monitoring potential dependent H2, O2 and CO2 formation. At oxidizing potentials, we did not observe oxygen evolution, only carbon corrosion. In the presence of vanadium, an increase in CO2 and H2 formation at high respectively low potentials was observed.

The DEMS method is capable to monitor side reactions occurring in VRFBs. Therefore, it is a useful tool to develop electrode materials, which exhibit a higher corrosion resistivity.

1. Eifert L, Banerjee R, Jusys Z, Zeis R (2018) Characterization of Carbon Felt Electrodes for Vanadium Redox Flow Batteries: Impact of Treatment Methods. J Electrochem Soc 165:A2577–A2586. doi: 10.1149/2.0531811jes

2. Colmenares LC, Wurth A, Jusys Z, Behm RJ (2009) Model study on the stability of carbon support materials under polymer electrolyte fuel cell cathode operation conditions. J Power Sources 190:14–24. doi: 10.1016/j.jpowsour.2009.01.078

3. Ashton SJ, Arenz M (2012) Comparative DEMS study on the electrochemical oxidation of carbon blacks. J Power Sources 217:392–399. doi: 10.1016/j.jpowsour.2012.06.015

4. Pérez-Rodríguez S, Sebastián D, Lázaro MJ, Pastor E (2017) Stability and catalytic properties of nanostructured carbons in electrochemical environments. J Catal 355:156–166. doi: 10.1016/j.jcat.2017.09.019

5. Taylor SM, Pătru A, Perego D, et al. (2018) Influence of Carbon Material Properties on Activity and Stability of the Negative Electrode in Vanadium Redox Flow Batteries: A Model Electrode Study. ACS Appl Energy Mater 1:acsaem.7b00273. doi: 10.1021/acsaem.7b00273

6. Eifert L, Banerjee R, Jusys Z, Zeis R (2018) Differential Electrochemical Mass Spectrometry of Carbon Felt Electrodes for Vanadium Redox Flow Batteries. ACS Appl Energy Mater 1 (12), 6714-6718 doi: 10.1021/acsaem.8b01550

Figure 1