bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Predicting Properties of Complex Interfaces for Photoelectrochemistry: Challenges and Strategies
Authors: Wood Brandon C. , Ogitsu Tadashi , Pham Tuan Anh
Published: February 2020

Processes occurring at solid-gas, solid-liquid, and solid-solid interfaces are critical to the functionality of most energy storage and conversion devices. However, surfaces and interfaces often exhibit properties that are qualitatively different from their bulk counterparts, preventing straightforward inference of their structural, chemical, and transport characteristics. Moreover, surfaces and interfaces in many operating devices tend to be highly heterogeneous, which introduces additional complexities that must be addressed by diagnostic methods. Predictive modeling based on ab initio simulations offers a unique set of tools for unbiased understanding of interfaces that can operate in tandem with high-fidelity experimental characterization. Indeed, recent advances in hardware, algorithms, and methods have significantly broadened the space of systems accessible to simulations. Nevertheless, accessing the full chemical and structural complexity of interfaces under realistic operating conditions remains a significant challenge for predictive simulations.

In this talk, I will begin by reviewing some of the key difficulties associated with predictive modeling of complex interfaces, with specific reference to solid-liquid and solid-solid interfaces in materials for photoelectrochemical water splitting. Next, I will show how ab initio molecular dynamics can be combined with advanced X-ray spectroscopy (XAS, XES, XPS) and other high-fidelity experimental probes to enable more realistic models of surfaces and interfaces in semiconductor photoelectrodes that go beyond idealized approximations. I will review our recent efforts applying this synergistic approach to study the structural, chemical, and transport properties of III/V semiconductor photoelectrodes under electrochemical and photoelectrochemical operation. I will show how theoretical modeling and experimental characterization operate hand-in-hand in this regard, with experiments aiding the validation and assembly of accurate interface models, and theory aiding the interpretation of complex spectra. The examples will specifically highlight the importance of accounting for structural and chemical changes induced by the presence of the interface under electrochemical conditions, such as surface oxidation and reconstruction, which profoundly alter photoelectrode behavior with consequences for photoelectrochemical durability and efficiency.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
(Invited) The Center for Hierarchical Materials Design: Realizing the Promise of the Materials Genome Initiative
Authors: Voorhees Peter W , DePablo Juan , Olson Greg
Published: February 2020

The classical materials creation process involves a laborious procedure wherein intuition drives the design of a material that is then created, and tested. In most cases, the design goals are not attained, and this costly procedure is repeated. The Materials Genome Initiative (MGI) seeks to replace this process and thus bring innovative new materials into commercial applications faster and at a lesser expense. The Center for Hierarchical Materials Design (CHiMaD) is the NIST-sponsored Center of Excellence for Advanced Materials Research focusing on developing the next generation of computational tools, databases, and experimental techniques in order to enable the accelerated design of novel materials and their integration into industry. To illustrate the potential of the MGI, we are designing a wide range of materials from Co-superalloys to block co-polymers for nanolithography. Each of these design efforts requires databases and simulation. A discussion of the databases, data mining and materials simulation efforts will be given.
Synthetic Polypyrrole/Titanium Dioxide (Ppyl/TiO2) Nanocomposite As Potential Electroactive Material for the Voltammetric Quantification of Sulfamoxole
Authors: Khan AB Lateef , Jain Rajeev
Published: February 2020

An extremely electro-active polymer nanocomposite material of polypyrrole and titanium dioxide (Ppyl/TiO2) has been synthesized from pyrrole and titanium dioxide using interfacial polymerization method. The synthesized nanocomposite was used as a voltammetric sensor (Ppyl/TiO2/GCE) by modifying glassy carbon electrode (GCE) for the quantification of sulfamoxole (SLM). The synthetic nanocomposite material before modification was characterized by various spectral techniques like infrared (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Moreover the developed sensor was also characterized by electrochemical impedance spectroscopy and various voltammetric techniques. The developed Ppyl/TiO2/GCE sensor showed an excellent electroanalytical performance than the electrodes i.e., Ppyl/GCE, TiO2/GCE and bare GCE. The constructed sensor under optimized experimental procedure showed the linear response for the oxidation of SLM over a concentration range from 1.25μgmL−1 to 12.50μg mL−1 having correlation coefficient of 0.9980 (r2) with 1.24 µg mL−1 limit of detection and 4.15 µg mL-1 limit of quantification. The sensor exhibited the superb sensitivity for the detection of (SLM) with reproducibility of 3.19% relative standard deviation (RSD). The proposed method was further effectively applied for the analysis of SLM in pharmaceutical formulation with a recovery of 99.50 % to 100.73 %.

KEYWORDS: Nanocomposite, Sulfamoxole, Polypyrrole, Glassy Carbon Electrode, Voltammetric Sensor.

Figure 1
Electrochemical Proximity Assay of Picomolar Platelet-Derived Growth Factor through Combined Surface Plasmon Resonance, Electrochemistry, and Fluorescence Spectroscopy Approach
Authors: Zhou Lang , Chin Bryan A , Simonian Alex
Published: February 2020

Platelet-derived growth factor (PDGF) is a potential cancer marker, which will play an important role in early detection of cancers. Due to its trace amounts in contrast to abundant proteins and other interfering species in blood sample, it is difficult to be detected. Electrochemical Proximity Assay (ECPA) is an extremely flexible and sensitive technique with high potential for quantitation of a variety of proteins in clinical laboratory settings or at the point-of-care systems. In this study, we applied ECPA strategy on the PDGF recognition to achieve high sensitivity and specificity. Different with previous ECPA approach in which signals are only read out by electrochemical measurement, three characterization techniques including surface plasmon resonance, electrochemistry and fluorescence spectroscopy are combined together here so that these techniques are capable of cross-validating and complementing each other.

With the combined advantages of these techniques, the limit of detection of PDGF quantification reaches as low as picomolar level. More importantly, the cross-validation of signals contributes to identification of the interference from non-specific binding, and further improvement of the detection accuracy. In this research, the influence factors such as concentration of biosensor’s components, injection time and flow rate were studies, the response linear range, sensitivity and selectivity of PDGF detection were obtained. Furthermore, the mechanisms of action and dynamics of sensing and protein recognition in the process of PDGF recognition was investigated. This work not only provides an accurate quantitation information for biomarker PDGF, but allows a fundamental understanding of the biosensor formation with an unprecedented level, which can overcome several key limitations of current, widely-used surface characterization technologies.
Exploring Key Descriptors of Solid Electrolyte Interphase Formation in Lithium Ion Batteries through Atomistic Simulations
Authors: Boyer Mathew J , Hwang Gyeong S
Published: February 2020

Lithium ion batteries (LIBs) have allowed for a technological revolution in portable electronics, power tools, and electric vehicles. Future improvements, however, require an advancement of existing battery technology to provide for faster charging and larger capacities, while maintaining safety and longevity. This fundamentally represents a knowledge and materials challenge that needs to develop a deeper understanding of electrode and electrolyte materials as well as their interfaces. Electrolyte and electrode materials used in LIBs have been studied separately to a great extent, however the structural and dynamical properties of the electrode/electrolyte interface still remain largely unexplored despite its critical role in governing battery performance. In particular, a key issue restraining the utilization of high-energy density anode materials, such as silicon (Si), is their inability to form a stable interphase during charging which results in continuous capacity fade or even cell failure. The design of better storage devices may be improved through a greater fundamental understanding of the formation of the solid electrolyte interphase (SEI) at the anode/electrolyte interface through atomistic computer simulations. We have utilized molecular dynamics (MD) simulations to correlate the bulk composition of the electrolyte to the interfacial structure and its effect on the transport behavior of key intermediates in the reductive decomposition of this electrolyte at a graphitic carbon electrode. Our study clearly demonstrates that the interfacial structure is sensitive to the molecular geometry and polarity of each solvent molecule as well as the surface structure and charge distribution of the negative electrode. Such quantitative analysis of the molecular arrangements at the electrode/electrolyte interface improves the understanding and description of electrolyte decomposition and SEI formation. Using MD and metadynamics techniques, we have systematically studied how factors such as the bulk composition of mixed carbonate electrolytes, precipitation of lithium fluoride (LiF, a result of the unstable PF6- anion species) onto the anode, and some commonly utilized additives (shown to improve the quality of the SEI layer) influence the transport and accumulation of decomposition products/intermediates. In this talk, we will present some of our recent findings including what we believe to be key descriptors in to predicting the decomposition products arising from the electrochemical reduction of the electrolyte. This improved understanding provides design principles for future investigation into forming a stable SEI on high-energy anodes such as Si.
Developing Cycle-Stable Sn-Based Alloys for Anode Application in Na-Ion Batteries
Authors: Wang Wenhui , Li Quan
Published: February 2020

Sn is a most promising anode candidate for Na-ion battery, due to its high capacity (847 mAh/g or 1210 Ah/L) and low average operating voltage (~0.25 V vs. Na/Na+). However, its cycle stability is limited by significant volume change, stress built-up, and Sn aggregation during charge/discharge cycles.

The present work attempted to tackle this outstanding problem by introducing other elements to form binary or ternary Sn-based alloys. Although the cycling stability of the Sn-based alloy were significantly improved when compared to pure Sn metal, we found that continuous segregation of Sn from the alloy during the cycling process remained a major problem, causing the deterioration of the alloy anode. We showed that a few other approaches can further enhance the cycling stability of the Sn-based alloys. In many cases, a compromise is needed between the capacity and cycle stability of the alloy anode.

This work is supported by RGC/GRF under project No. 14316716
Graphene-Based Anode for Li-Ion Battery
Authors: Fang Hui , Carson Oliver , Ellinwood Clayton , Lin Feng , Bao Jiming
Published: February 2020

We attempt to comparatively study the battery performance due to different kinds of graphene-based anodes. The lithium-ion full battery based on a lithium iron phosphate cathode and a graphene-based anode was assembled. Various graphene-based anodes, including graphene nanoflakes, graphene/graphite composite, magnetically aligned graphene flakes, were investigated in this study. The electrochemical performance of full battery with these graphene-based anodes will be reported.
A Solvent-Free Electrode Coating Technique for All Solid State Lithium Ion Batteries
Authors: Graebe Heiko , Netz Andreas , Kwade Arno
Published: February 2020

Solid state lithium-ion batteries are one of the promising candidates to power future electric and

hybrid electric vehicles. They offer outstanding safety and power density. The ability to exchange the

liquid electrolyte/separator system by a single component and use a metal lithium anode provides

encouraging advantages for the use of solid state batteries. In general a solid state electrode is

produced by dissolving the polymeric binder in a solvent and disperse the active material and

conductive additives in the solution. Commonly toxic solvents like n-methyl-2-pyrrolidion (NMP),

acetonitrile, methanol etc. are used in this process. Some of these are known to be carcinogenic and

often they have to be removed from the electrode, which results in energy consumption and further

process steps. The challenge is to develop a process which does not require any kind of such a solvent.

The present work investigates a solvent-free mixing and hot pressing technique to prepare both the

solid state lithiumironphosphate (LFP) cathodes and polyethylenoxide (PEO) based electrolytes. The

powder treatment is essential to produce mechanically stable and electrochemically active electrolytes

and electrodes. For the preparation, all ingredients were premixed in a dual asymmetric centrifugal

mixer and filled into a heated pressing die. Ideal process parameters such as pressure and heating time

were investigated. By way of example, figure 1 illustrates a flexible electrolyte film containing

PEO/LiTFSI with a molar ratio of 10:1. It can also be shown that the ionic conductivity of the solid

state electrolytes is in the same range (10-3 S/cm at 80°C) compared to their solvent based coated

counterparts. Additional determination of the electrolyte and electrode performance vs. Li anode is

made with respect to the discharge rate capability.

The lab-scale processing shown below demonstrates a first proof of function of all solid state cathode

and separator and may offer a much simpler method for such cathode and separator manufacturing

overall, with less process steps and potential cost saving and functional advantages. In conclusion, it

seems to be a promising process for further development to demonstrate scalability for future cell

production.
Experimental and Computational Investigation on the Crystal Structure, Stability, and Li Ion Conductivity of Undoped and Doped Garnet-Type Solid Electrolytes
Authors: Jalem Randy , Morishita Yasuyuki , Okajima Takashi , Kondo Yuki , Takeda Hayami , Nakayama Masanobu
Published: February 2020

Garnet solid electrolytes are regarded as amongst the most promising class of materials for the realization of all-solid-state Li ion batteries, demonstrating good stability vs Li metal (anode) and exhibiting conductivity values that come close to conventional liquid- and/or organic-based electrolytes (on order order of 10-3 S/cm)1,2. These properties are strongly governed by structure stability (thermodynamic and electrochemical), doping effects, and the dominating Li ion conduction mechanism in the garnet framework. In this respect, a clear and fundamental understanding of the garnet material itself is crucial for the formulation of effective strategies for property optimization. Unfortunately, elucidation by experiment alone are met with difficulties. Even conductivity values for the same garnet composition can vary significantly as can be seen in the literature. In the case of electrochemical stability, the decomposition product(s) in the oxidative voltage regime, for example, could be difficult to detect. Meanwhile, ascertaining the actual site preference and distribution of dopants is also not straightforward and could depend on the preparation condition of the garnet powder. When determining bulk and grain boundary conductivity, separating the bulk and grain boundary contributions of resistance in impedance measurements can also become problematic.

By experiment and computational modelling, we attempted to clarify some of the above issues as well as tried to resolve some of the discrepancies existing in the literature. Specifically, we studied the electrochemical stability,3,4 dopant distribution and local structure,5 and Li ion transport properties5,6,7. As an example, for experiment, results will be shown related to the charge process behavior of an air-isolated Li ion battery with a garnet solid electrolyte, and then use modelling to aid in clarifying the origin of capacity fading. Another example, for computation, we employed various techniques such as first-principles density functional theory (DFT), augmented plane-wave method, computational NMR, force-field approach, and molecular dynamics in order to analyze the effects of gallium doping in garnet Li7La3Zr2O12. Our results could provide insights and fresh view, for both experimentalists and computationalists, on the state and the future direction that could be taken for solid electrolyte research.

REFERENCES

1Li et al., J. Mater. Chem. 2012, 22, 15357-15361.

2 Bernuy-Lopez et al., Chem. Mater. 2014, 26, 3610-3617.

3 Nakayama et al., Phys. Chem. Chem. Phys. 2012, 14, 10008-10014.

4 Jalem et al., J. Mater. Chem. A 2016, 4, 14371-14379.

5Jalem et al., Chem. Mater. 2015, 27, 2821-2831.

6 Jalem et al., J. Phys. Chem. C 2015, 119, 20783-20791.

7 Jalem et al., Chem. Mater., 2013, 25, pp 425-430.
Graphene-Lii Composite Cathodes for Lithium-Iodine Batteries
Authors: Kim Sanghyeon , Kim Sung-Kon , Braun Paul V
Published: February 2020

Development of high energy and power density secondary batteries is of great fundamental and applied interest. Systems which provide high power, without a significant reduction in energy are important for next-generation hybrid and all-electric vehicles. Li-iodine cells have been considered promising because of fast electrochemical conversion of the iodine/triiodide redox pair. To date, there only a few reports on rechargeable Li-iodine cells, in-part because of the drawbacks of iodine. Iodine is highly soluble in aprotic electrolytes, leading to self-discharge due to shuttling. Li-iodine cells use Li metal as an anode, however, Li metal can form dendrites which lead to shorting during cycling. Iodine is volatile even at room temperature, leading to cell fabrication challenges. Finally, iodine based electrodes suffer from low electrical conductivity. Here, we present the fabrication of a reduced graphene oxide (rGO)/LiI composite cathode with a gravimetric energy density of around 270 mAh/g which addresses some of these problems and demonstrate its operation in a full cell. LiI was uniformly coated on rGO by a solution-based method directly forming a free standing electrode. The use of LiI enables use of lithium-free anodes such as graphite, silicon, and tin. Its high melting (469 °C) and boiling points (1171 °C) provide the better thermostability compared to iodine and enables the use of various high temperature synthesis methods. The rGO facilitates rapid electron transfer and suppresses the dissolution of active materials species during cycling. We observe stable cycling performance of rGO/LiI electrodes at both low and high current densities. Promisingly, the rGO/LiI electrodes show good rate performance and a small hysteresis at high c-rates.
Synthesis of Mixed Na2Ti3O7/Na2Ti6O13 Sodium Titanates with Different Phase Ratios and Their Lithium Insertion Properties
Authors: Cech Ondrej , Vanýsek Petr , Částková Klára , Čudek Pavel
Published: February 2020

Sodium titanate nanorods consisting of two phases were successfully synthesized by microwave assisted hydrothermal synthesis. The electrochemical behavior during lithium ion insertion and deinsertion was studied depending on the different ratio of Na2Ti3O7/Na2Ti6O13 in the sample. Hydrothermally treated precipitates were calcined at temperatures 700°C, 800°C and 900°C. The purity and crystallographic composition of the samples were examined by XRD and the morphology was observed by SEM. Electrochemical behavior was studied by cyclic voltametry and galvanostatic cycling, all measurements were performed in three electrode cells with metallic sodium as counter and reference electrodes. Samples with three phase compositions were prepared: pure trititanate Na2Ti3O7, pure hexatitanate Na2Ti6O13 and mixture of both in the ratio of 42% Na2Ti3O7 to 58% Na2Ti6O13. Best capacity achieved by prepared samples was 145 mAh/g at 0.1C.

Figure 1
The Effect of Li Ion Dissociation Level in Gel Polymer Electrolytes on Electrochemical Performance of Li-O2 Batteries
Authors: Chamaani Amir , Chawla Neha , Safa Meer , El-Zahab Bilal
Published: February 2020

Li-O2 batteries have been recently considered as next generation of energy storage systems for electric vehicle application due to their high specific energy densities, which are comparable to gasoline [1]. Li-O2 batteries however suffer poor cycling and reachability due to a sever electrolyte decomposition [2]. It has been shown that the electrolyte decomposition by-products such as lithium carbonate species gradually cover the surface of cathodes and shuts down the batteries quickly [3]. Although many attempts have been made to overcome the detrimental formation of these carbonate species on the surface of cathode, their formation and electrolyte instability still remains a very big challenge in this filed [4]. Recently, it has been reported that tailoring the coordination of Li ion and solvent molecules in Li-O2 battery electrolytes is a promising method to improve the electrolyte stabilities [5,6].

In this study, we report that the inclusion of inorganic fillers in gel polymer electrolytes using different salt concentration can reduce the electrolyte decomposition by-products such as lithium carbonate species during the Li-O2 battery cycling. The improved electrochemical performance of Li-O2 batteries can be attributed to the interaction of filler with Li salt which in turn can tailor the interaction of Li ion and solvent molecules. To asses our hypothesis different electrochemical tests including in-depth electrochemical impedance spectroscopy, lithium transference number measurements along with other characterization methods such as Raman spectroscopy has been used.

[1] G. Girishkumar, B. McCloskey, A.C. Luntz, S. Swanson, W. Wilcke, Lithium-air battery: Promise and challenges, J. Phys. Chem. Lett. 2010,1, 2193–2203.

[2] B. D. McCloskey, C. M. Burke, J. E. Nichols and S. E. Renfrew, Chem. Commun., 2015, 51, 12701–12715

[3] S. A. Freunberger, Y. Chen, N. E. Drewett, L. J. Hardwick, F. Bardé and P. G. Bruce, Angew. Chemie - Int. Ed., 2011, 50, 8609–8613

[4] R. Younesi, G.M. Veith, P. Johansson, K. Edstrom, T. Vegge, Lithium salts for advanced lithium batteries: Li-metal, Li-O2, and Li-S, Energy Environ. Sci.,2015, 8, 1905–1922.

[5] F. Li, T. Zhang, Y. Yamada, A. Yamada and H. Zhou, Adv. Energy Mater., 2013, 3, 532–538.

[6] B. Liu, W. Xu, P. Yan, X. Sun, M. E. Bowden, J. Read, J. Qian, D. Mei, C. M. Wang and J. G. Zhang, Adv. Funct. Mater., 2016, 26, 605–613.
Comprehensive Electrochemical Study of the Role of Transition Metals in O3-Type Na[Ni
x
Co
y
Mn
z
]O2 (x=1/3, 0.5, 0.6, and 0.8) Cathodes for Sodium-Ion Batteries
Authors: Hwang Jang-Yeon , Yoon Chong seung , Choi Min-Jae , Belharouak Ilias , Sun Yang-Kook
Published: February 2020

Sodium ion batteries (SIBs) have attracted significant interest due to the abundant natural resources of Na and their similar chemistry to Li ions.5 O3-type layered structured transition metal oxides appear to be attractive based on the success of using layered LiMO2 cathodes in LIBs. Recently, our group introduced micro-sphere NaMO2 (M=Ni, Co, and Mn) cathodes with high energy density and high thermal stability.1-3 However, the relationships between transition metal composition and the electrochemical and related structural properties in O3-type layered NaMO2compounds have not been systematically studied.

In this study, a comprehensive study of Na[Ni
x
Co
y
Mn
z
]O2 (x=1/3, 0.5, 0.6, and 0.8) cathodes is carried out to determine the optimal composition as the electrochemical, structural, and thermal properties in O3-type layered cathodes are strongly dependent on the transition metal composition. Here, the role of each transition metal in [Ni
x
Co
y
Mn
z
]O2 cathodes is identified via electrochemical property characterization, structural analysis, and thermal stability testing. Briefly, an increase of the Ni fraction resulted in an increasingly higher capacity but is accompanied by progressively poor capacity retention. On the other hand, the Co metal played an important role in stabilizing the structure, while the Mn content contributed to enhancing the capacity retention and thermal stability. The present study highlights the importance of appropriately balancing the transition metal composition in a layered Na[Ni
x
Co
y
Mn
z
]O2 cathode. Furthermore, this work provides a design guideline for developing an ideal Na[Ni
x
Co
y
Mn
z
]O2 cathode with both high capacity and optimal cycle retention in addition to thermal stability.

References

[1] Y. Li, Y.-S. Hu, X. Qi, X. Rong, H. Li, X. Huang and L. Chen, Energy Storage Materials, 2016, 5, 191-197.

[2] J. Y. Hwang, S. M. Oh, S. T. Myung, K. Y. Chung, I. Belharouak and Y. K. Sun, Nat. Commun., 2015, 6, 6865.

[3] E. de la. Llave, V. Borgel, K. J. Park, J. Y. Hwang, Y. K. Sun, P. Hartmann, F. F. Chesneau and D. Aurbach, ACS Appl.
Mater. Interfaces, 2016, 8, 1867-1875.
Environmental-Friendly LiCoO2 Recycling from Libs Under the Assistance of Ultrasonic and Supercritical CO2
Authors: Dai Changsong , Mu Deying , Liu Yuanlong
Published: February 2020

The rising demand for lithium calls for fully processing and using of all viable resources. Different processes in vogue aiming at recycling spent LIBs can be mainly divided into pyro/hydrometallurgical technologies. Pyro-processes burn off the organic toxic and flammable electrolytes and binder, while Hydro-processes may produce amounts of wastewater which contains complex chemical substances for further treatment. Herein, we aim at recovery the LiCoO2 from LIBs directly without bringing secondary pollutant. The cathode was shredded ( ~1.5 cm2 size) to separate active metal materials from aluminum foil in NMP (N-methyl-2-pyrrolidone) at room temperature under the ultrasonic assistance for 30 mins. The electrolyte and binder were dissolved in NMP, and later were recovered by Supercritical CO2 .NMP was reused and eventually recycled back by evaporation. The active materials was dried in vacuum for 12 hours at 100 ℃. XRD and SEM analysis indicated that the recycling material was LiCoO2 with high purity, and the electrochemical properties were tested by assembling coin cell batteries. The initial specific discharge capacity was more than 150mAh/g. GC-FID was investigated to reflect the unchanging composition of NMP. Our research fully care about environmental benign and economic feasibility.This technological process realizes the recycling of flammable liquid electrolyte and cathode materals and avoides the environmental harzards.

Figure 1
Electrochemical Characteristics of Advanced Sulfur-Based Cathode Material for Lithium-Sulfur Batteries
Authors: Nguyen Dan Thien , Song Seung-Wan , Hoefling Alexander , Theato Patrick , Lee Young Joo
Published: February 2020

The demands for high-energy density and low cost advanced batteries, which can replace currently used lithium-ion batteries, are increasing for their possible applications to electric vehicles and energy storage systems. Lithium-sulfur (Li-S) batteries are one of the most attractive candidates for next-generation batteries due to high theoretical capacity of sulfur of 1672 mAhg-1 and earth-abundance and low cost of sulfur. However, the commercialization of Li-S batteries is being hindered by several issues such as the insulating nature and structural instability of sulfur, polysulfides shuttle and electrode-electrolyte interfacial instability, and as a result, limited cycle life and performance. Recently, a new class of sulfur copolymer materials is appealing as cathode active materials for Li-S batteries, which can exhibit improved performance compared to elemental sulfur.1-2There is however little report on a basic understanding of electrochemical characteristics of sulfur copolymer cathode materials. In this presentation, we discuss the material’s electrochemical characteristics and the critical factors affecting cycling performance of lithium cells.

Acknowledgements: This work was supported under the framework of international cooperation program managed by National Research Foundation of Korea (2015K2A5A3000068) and German Academic Exchange Service (57141898).

References

1. W. J. Chung et al., Nat. Chem., 5, 518 (2013).

2. H. Kim, J. Lee, H. Ahn, O. Kim and M. J. Park, Nat Commun
., 4, 2985 (2013).

3. D. T. Nguyen, A. Hoefling, Y. J. Lee, P. Theato, S.-W. Song, The 229th Meeting of Electrochemical Society, Abstract #284, San Diego, May 31 (2016).
ZnCo2O4/Rgo Nanocomposites with Superior Electrochemical Performance for Lithium Ion Batteries
Authors: Lam Kwok Ho , Chen Chang , Hou Xianhua
Published: February 2020

Owing to the high theoretical capacities and high abundance, the binary and ternary transition metal oxides (TMOs) have been widely studied as the next generation anode materials for rechargeable lithium-ion batteries (LIBs). However, TMOs electrodes still have some fatal flaws, such as large volume, poor cycling stability and detrimental structural collapse during the charge/discharge process. Development of hybrid carbon-based TMOs nanocomposites is one of the promising ways to solve the above limitations to promote the energy storage performance for the needs of high-power electric vehicles (EVs) and LIBs.

Among the polynary TMOs, cubic spinel crystallize ZnCo2O4 has drawn considerable attention because of its unique crystalline structure and electrochemical reaction mechanism. Although different preparation methods for the specific electrochemical performance have been reported, those special morphologies of ZnCo2O4 electrodes are still needed to further improve to meet the needs of high-power applications.

Two-dimensional reduced graphene oxide (rGO) is known to be one of the promising carbon-based materials as an excellent building block and an ideal conductive platform for anode materials. Besides, oxygen-containing groups are abundant on the surface of the rGO so that these groups are very reactive to oxidize the electrolyte and subsequently minimize the electrochemical instabilities. Furthermore, rGO sheets have a relatively low volumetric change during the electrochemical process. It is expected that intimate interactions between TMOs and rGO cannot only promote Li+/electrons transfer, but also inhibit the volume expansion and aggregation during the electrochemical cyclic process.

Chemically integrated hybrid ZnCo2O4/rGO nanocomposites have been synthesized through a polyol process. Ultrafine ZnCo2O4 particles grow and embed on the surface of rGO sheets. Owing to the special nanoparticles-on-sheets structure, the composites exhibit the excellent initial electrochemical discharge capacity for rechargeable LIBs (~1300 mAh g-1 at the current density of 200 mA g-1), high rate stability (~500/550 mAh g-1 at 4000 mA g-1) and outstanding electrochemical cyclic performance (~650/~660 mAh g-1 at 2000 mA g-1 after 2000 cycles with a capacity retention of ~65 %). The superior performance of the synthesized composites can be ascribed to the advantage of nanoparticles. With the successful synthesis of hybrid ZnCo2O4/rGO nanocomposites, the facile strategy can extend to synthesize the composites with other TMOs for much promising storage applications.
Atomic Level Surface Structure of Lithium Layered Cathode Material for Lithium-Ion Batteries
Authors: Ahn Juhyeon , Kim Jong Hak , Cho Byung Won , Chung Kyung Yoon , OH Si Hyoung
Published: February 2020

The structural rearrangement on the surface of lithium transition metal layered oxide is a critical issue on affecting the ion transport behavior in lithium-ion batteries. In layered metal oxides, the local elemental segregations before and/or after cycling is closely associated to the structural evolution, which lead to voltage and capacity fades and poor rate capability. In this study, we show the control of 3d or 4d transition metal segregations and their chemical inhomogeneity on the crystallographic surface planes in lithium- and manganese-rich layered oxides. By developing synthesis processes based on the modification of particle morphology, the relationship between the structural changes and the electrochemical properties is demonstrated by atomic-scale observations. It will be a significant investigation to understand the general trends of surface chemistry of lithium layered oxide, development of efficient surface layer and related diffusion characteristics for ion transportation.

Figure. EDS mapping taken along the [010]monoclinic zone axis for relative distribution of chemical species on the surface layer of lithium- and manganese-rich layered oxide (LMR). (a) Zr-segregated LMR. (b) Zr-unsegregated LMR. (c) Zr-uncontained LMR.

This work is supported by the National Research Foundation of Korea (NRF-2011-C1AAA001-0030538).

Figure 1
Use of RF Glow Discharge Optical Emission Spectroscopy for the Study of Lithium Ion Batteries
Authors: Chausseau Matthieu , Hunault Philippe , Savadkouei Kayvon , Chapon Patrick , Gaiaschi Sofia
Published: February 2020

RF Glow Discharge Optical Emission Spectroscopy (RF GD-OES) provides elemental depth profile analysis for both conductive and non-conductive samples, allowing the study of coatings, thin and thick films but also on diffusion effects between layers and materials.

The analysis is done by sputtering the sample and detecting in real time all elements using a high resolution optical spectrometer. All elements from H to U can be measured using RF GD-OES and the technique is showing a good sensitivity for light elements such as Li, C, H, O or F.

With its ability to perform depth profiling with a nanometric resolution and to go up to 150 µm down in the sample, RF GD-OES is a perfect tool for the study of Lithium Batteries and gives complementary information to SIMS or XPS at a much lower cost and within minutes.

Some specific accessories especially developed for the analysis of Lithium batteries will be presented as well as results on the study damaged electrodes and the identification of the cause of it and the study of electrodes after charge and discharge cycles and how elements can diffuse from the electrolyte or the binder. Other possible applications of RF GD-OES will be presented as well as a brief comparison of its characteristics compared to XPS or SIMS.
Phase Content and Conductivity of Aluminum- and Tantalum-Doped Garnet-Type Lithium Lanthanum Zirconate Solid Electrolyte Materials
Authors: Zhang Xingxing , Fergus Jeffrey
Published: February 2020

Garnet-type Li7La3Zr2O12 (LLZO) is an attractive solid electrolyte material for lithium batteries. Obtaining the desired high conductivity requires formation of the cubic phase. Small amounts of aluminum and/or tantalum have been shown stabilize the cubic crystal structure and increase the conductivity. In this work, aluminum- and tantalum-doped LLZO have been prepared and evaluated with materials characterization techniques and impedance spectroscopy. The dopant additions stabilized the cubic phase and increase the conductivity of the material.
(Invited) Photoluminescnece Brightening in Single Walled Carbon Nanotubes
Authors: Hou Zhentao , Amori Amanda , Cogan Nicole , Krauss Todd D
Published: February 2020

Semiconducting single-walled carbon nanotubes (SWNTs) are fundamentally interesting and technologically relevant materials with size tunable absorption and emission across a range of visible and near infrared wavelengths. However, several important aspects of their photophysical properties are not known in enough depth to predict how SWNTs will behave as part of larger integrated nanosystems. In particular, simple concepts such as the fundamental factors that affect photoluminescence efficiency (PL QY) are not well understood for SWNTs.

We recently found that for DNA-wrapped SWNTS, the SWNT PL QY can be increased substantially in the presence of small amounts of mildly reducing molecules such as dithiothreitol (DTT) and Trolox. We will present comprehensive studies of the molecular-induced changes in PL from SWNTs suspended in several other commonly used surfactants. For example, upon addition of the reducing agents, sodium dodecyl sulfate (SDS) wrapped SWNTs showed a 4-fold PL intensity increase while sodium cholate (SC) wrapped SWNTs showed PL decrease by ~45%. Minimal change in PL was observed for SWNTs dispersed in sodium dodecylbenzene sulfonate (SDBS) and sodium deoxycholate (DOC). By using a state-of-the art NIR sensitive APD, we were able to acquire time resolved PL data from each sample. For SWNTs that were brightened (darkened), the non-radiative rate decreased (increased) and the radiative rate increased (decreased). Our preliminary conclusion is that adding the reductants causes a change in the molecular structure of the surfactant on the SWNT, which changes the local dielectric constant as well as the interaction of the exciton with the molecular orbitals of the surfactant.

We will also present recent data on the PL brightening of individual SDS wrapped SWNTs, whereby we found the PL efficiency enhancement varied substantially among individual nanotubes, with some brightening by up to 6.5 times while others brightened by only 16%. Studies of NTs longer than the diffraction limit reveal the surprising finding that upon adding the reductants, the NTs brightened uniformly, as determined from the PL image. Since non-uniform brightening would result from consecutive interactions with individual point defects, the observation of uniform PL brightening is consistent with the interpretation that the reductants are causing changes in the local SWNT environment. Further, single step brightening across the entire NT followed by a constant, nonblinking PL level suggests the brightening effect could be due to as little as a single molecule interacting with the NT.
Structural and Electrochemical Characterizations of Waste Cooking Oil Based Nano Carbons As Electrode Materials for Lithium Ion Capacitors
Authors: Arie Arenst Andreas , Hadisaputra Lukito , Susanti Ratna Frida , Lee Joong Kee , Devianto Hary
Published: February 2020

Synthesis of nanocarbon on snake fruit-peel’s activated carbon from waste cooking oil palm was conducted by a nebulized spray pyrolysis process (NSP) by varying the processing temperature from 650 -750 ºC. Ferrocene was used as a catalyst with fix concentration of 0.015 g/ml on each experiment variation. The structure of nanocarbon was formed as the carbon nanopsheres (CNS). As the temperature was increased from 650 to 750 ºC, the yield of formed CNSs became larger. Based on the characterizations using scanning electron microscopy (SEM), x-ray diffraction (XRD), raman spectroscopy, and BET test results, we determined that the temperature 750 ºC was the optimum condition for the growth of nanocarbon. Material from NSP process at 750 ºC was tested by its performance as an electrodes in lithium base supercapacitor with cyclic voltammetry method and we obtained a specificcapacitance of 79.57 F / g at a scan rate of 0.1 mV / s and voltage range from 2.5 - 4 V.
Delivery of Large Volume Single Walled Carbon Nanotube Sensor Liquid Via Hydrogel Encapsulation
Authors: Iverson Nicole M , Hofferber Eric M , Walsh Sophia C , Stapleton Joseph A , Adams Janelle J , Bart Victoria A
Published: February 2020

Single walled carbon nanotubes (SWNT) are ideal in vivo fluorescent sensors due to their near infrared emission, specificity, and lack of photobleaching. Unfortunately, the small size of SWNT sensors allows for easy in vivo dispersion unless they are constrained, which frequently leads to interactions that destabilize SWNT sensing capabilities. Delivery of a liquid SWNT sensor allows for physical constraint without negative interactions between the sensor and the constraining material. Various methods of hydrogel encapsulation of large volumes of SWNT have been determined, providing a method to deliver macro-scale, biocompatible devices in vivo for extended SWNT sensor observation.
Interaction of Single-Walled Carbon Nanotubes (SWCNTs) with Photosynthetic Organisms
Authors: Antonucci Alessandra , Schuergers Nils , Boghossian Ardemis Anoush
Published: February 2020

For years, the distinctive optical and structural properties of single-walled carbon nanotubes (SWCNTs) have inspired the development of promising applications in the field of cell nanobiotechnology. In particular, the synergistic interaction of SWCNTs with photosynthetic organisms has the potential to enhance the native performance of biological machineries, paving the way for novel, renewable, and low cost solutions for light-harvesting, energy conversion, subcellular sensing, and DNA delivery. Recent studies have largely focused on enabling cellular uptake of SWCNTs by engineering the SWCNT surface through non-covalent side-wall functionalizations. Non-covalent functionalization with a rich variety of biomolecules and polymers has been shown to potentially increase SWCNT solubility and membrane translocation while endowing these nanostructures with enhanced biocompatibility.

We performed a systematic investigation of the effect of SWCNT functionalization on membrane penetration properties using a novel biological host. A custom-built optical setup was used for the unprecedented characterization of near-infrared fluorescence emissions of internalized SWCNTs. These results were used to inform fuctionalization design rules for SWCNT internalization, and more broadly, present a versatile approach towards imaging internalized SWCNTs in biological systems.
(Invited) Controlling Carbon Nanotubes By DNA: From Separation to Assembly
Authors: Zheng Ming
Published: February 2020

In this talk, I will present our latest result on atomic-structure-based separation of single-wall carbon nanotubes (SWCNTs) by DNA, as well as the controlled assembly of SWCNTs via DNA hybridization. In particular, I will describe a quick and easy precipitation based sorting method, a simple pattern underlying many DNA sequences that recognize specific SWCNT structures, and a robust process to wrap SWCNTs by DNA sequences to enable many different applications, including controlled assembly of SWCNTs.
Photoluminescent Readout of Molecular Information Using Local Sites Functionalized on Single-Walled Carbon Nanotubes
Authors: Shiraki Tomohiro , Onitsuka Hisashi , Shiraishi Tomonari , Nakashima Naotoshi
Published: February 2020

Near infrared photoluminescence (NIR PL) of semiconducting single-walled carbon nanotubes (SWNTs) is a unique feature based on the one-dimensional nanostructures. Recently, a very limited amount of chemical modification of SWNTs is reported to enhance NIR PL properties, in which oxygen atom doping as well as sp3defect doping are applied to the π-conjugated networks of the SWNT walls. As a result, quantum yield increment and emission wavelength shifts were observed.[1-3] Thus, the locally-functionalized SWNTs (local-f-SWNTs) are expected as novel NIR PL materials because quantum yields of pristine SWNTs are typically low and the tube structures defined by chiral indices determine emission wavelengths.

In this study, we utilize the PL of local-f-SWNTs to read out differences of molecular structures that are constructed at the modified sites by covalent or noncovalent approaches.[4,5] For example, a phenylboronic acid-modified local-f-SWNTs show PL wavelength shifting by attachment of saccharide molecules through molecular recognition at the modified sites, as shown in Figure.[5]

Thus, the present system would be applicable to a novel detection technique that converts molecular information to NIR PL towards future applications including bio-imaging/sensing.

References: [1] Weisman, R. B. et al., Science
2010, 330, 1656-1659. [2] Wang, Y. et al., Nat. Chem.
2013, 5, 840-845. [3] Nakashima, N. et al., J. Phys. Chem. C
2016, 120, 15632-15639. [4] Nakashima, N. et al., Sci. Rep.
2016, 6, 28393. [5] Nakashima, N. et al., Chem. Commun.
2016, 52, 12972-12975.

Figure 1
(Invited) Quasi Phase Transition in a Single File of Water Molecules Encapsulated inside (6,5) Carbon Nanotubes
Authors: Cambre Sofie , Ma Xuedan , Wenseleers Wim , Doorn Stephen K. , Htoon Han
Published: February 2020

The confinement of water molecules in one-dimensional channels leads to fascinating new properties which are of critical importance for many processes in biology, geology, catalysis and nanofluidics. Single-walled carbon nanotubes (SWCNTs) are one of the most promising model systems to investigate molecules under confinement. They combined atomically-precise diameters that deliver the necessary level of confinement with a weak interaction of the water molecules with their smooth inner walls. Despite significant efforts, theoretical predictions of the behavior and peculiar properties of a single-file chain of water water molecules (e.g. interesting for ultrafast proton transport) have proven to be very hard to validate experimentally.

In this work, we present temperature-dependent (4.2K up to room temperature) photoluminescence (PL) spectra of water-filled and empty chirality-sorted (6,5) SWCNTs. Superimposed on a linear temperature-depenent PL spectral shift of the empty tubes, an additional stepwise PL shift of the water-filled SWCNTs is observed at around 150K. With the empty SWCNTs serving as the ideal reference system, we can assign this observation to temperature-induced changes occuring within the single file molecular chain. Supported by new Molecular Dynamics simulations, we obtain the first experimental evidence of a quasi phase transition of the orientation of the molecular dipoles within such a one-dimensional single file chain of water molecules.
Smart Carbon Nanotubes Assemblies for High Throughput Filtration Devices
Authors: Maggini Laura , Copic Davor , De Volder Michael F. L.
Published: February 2020

Access to clean water is fundamental to maintain the basic standards of public health. The World Bank is estimating over a billion individuals lacking access to potable water, causing millions of deaths annually. Only few point-of-use technologies are available providing efficient removal of pollutants and pathogens. Hence there is a critical need to develop low-cost, sustainable and highly effective filtration technologies essential for undeveloped countries lacking water treatment infrastructures.

Since the Middle Ages, people have been using charcoal to filter water because of its exceptional ability to adsorb contaminants. With the advent of nanotechnology, new forms of carbon have been discovered (i.e. carbon nanotubes, CNTs), which have demonstrated impressive sorption capacities, and more spectacularly, have found to be able to efficiently remove viruses and bacteria from water. Unfortunately, methods need to be developed to organize CNTs into highly structured and well-understood materials for safe and efficient implementation in filtration devices.

Herein we report an unprecedented sequential engineering of the architecture of CNT materials by combining emulsification methods with colloidal self-assembly. This approach allows preparation of well-defined spherical CNT supraparticles, which upon assembly, give rise to a filter whose porosity and density can be precisely engineered, allowing full exploitation of the impressive decontaminating action of CNTs.