bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Conductive Biopolymers for Selective Metal-Devoid Electrocatalysis
Authors: Coskun Halime , Stadler Philipp 
Published: February 2020

Electrocatalysis can be useful in energy conversion, in particular for the production of synthetic fuels from renewable energy. However, this requires catalytic conductors, which sustain the reaction conditions that foremost occur in aqueous solution. Conducting polymers represent a chemically robust but conductive materials class that could be harnessed for aqueous electrocatalytic processes in order to facilitate the important reactions steps to electrosynthesize fuels.
In terms of CO2 reduction this has been demonstrated by using a conducting form of polydopamine.(1–3) This system no than other incorporates a richly functionalized backbone able to attach CO2 and electro-reduce to formate efficiently. We shed light on the relevant electro-activation of the incorporated functional themes in the biopolymer and compare this mechanisms to similarly efficient inorganic catalysts. We find that it is the actual nature of the incorporated theme that significantly influences its final selectivity. Such tunability enables the tailoring of selective and highly active catalytic surfaces from organic-functional matter. The functionalzed organic catalysts rely on different reaction mechanisms than state-of-the-art metal-based systems and possibly can be optimized as future sustainable contenders for metal-based electrocatalysts.

H. Coskun et al., Chemical vapor deposition - based synthesis of conductive polydopamine thin-films. Thin Solid Films. 645, 320–325 (2018).

X. Zheng et al., Sulfur-Modulated Tin Sites Enable Highly Selective Electrochemical Reduction of CO2 to Formate. Joule (2017), doi:10.1016/j.joule.2017.09.014.

H. Coskun et al., Biofunctionalized conductive polymers enable efficient CO2 electroreduction. Sci. Adv.
3, e1700686 (2017).
(Invited) Imperceptible Electronic Sensor Foils
Authors: Kaltenbrunner Martin 
Published: February 2020

Electronics of tomorrow will be imperceptible and will form a seamless link between soft, living beings and the digital world. Exploring the fundamental physics, mechanical form factors, and materials required to meet the needs of this new generation of soft electronics is driving multidisciplinary research worldwide. Weight, flexibility and conformability are pivotal for future wearable, soft and stretchable electronics to proliferate. The abilities to be imperceptible, epidermal, transient and self-healing are fueling the vision of autonomous smart appliances to be embedded everywhere, on textiles, on our skin, and even in our body.
We here introduce a technology platform for the development of large-area, ultrathin and lightweight electronic and photonic devices, including solar cells[1,2], light emitting diodes[3]and photodetectors[4], active-matrix touch panels[5], implantable organic electronics, imperceptible electronic wraps and “sixth-sense” magnetoception[6]in electronic skins. Air stable perovskite solar cells, only 3 µm thick, endure extreme mechanical deformation and have an unprecedented power output per weight of 23 W/g. Highly flexible, stretchable organic light emitting diodes are combined with photodetectors for on-skin photonics and pulse oximetry. E-skins with GMR-based magnetic field sensors equip the wearer with an unfamiliar sense that enables perceiving of and navigating in magnetic fields. These large area sensor networks build the framework for sensor skins that are not only highly flexible but become highly stretchable when combined with engineered soft materials such as elastomers, shape memory polymers or hydrogels. We show mobile health monitoring systems, smart, tissue-like electronics and soft machines that utilize tough hydrogels[7]as soft robots, generators and adaptive lenses.

References

[1] Kaltenbrunner et al, Nature Communications 3:770, 1-7 (2012)

[2] Kaltenbrunner et al, Nature Materials 14, 1032-1039 (2015)

[3] White et al, Nature Photonics 7,811–816 (2013)

[4] Yokota et al, Science Advances 2:e1501856 (2016)

[5] Kaltenbrunner et al, Nature 499, 458-464 (2013)

[6]GSC Bermúdez et al, Science Advances 4:eaao2623, (2018)

[7] Wirthl et al, Science Advances 3:e1700053, (2017)
Na+ Ion Transport in Glassy Electrolytes for Solid-State Sodium Ion Batteries: A Reactive Molecular Dynamics Study
Authors: Dive Aniruddha Mukund , Banerjee Soumik 
Published: February 2020

All solid-state sodium ion battery is a promising technology for electrical grid energy storage. The low ionic conductivity of solid-state electrolytes is a major challenge towards commercialization of solid-state sodium ion batteries. Sulfide glasses are potential electrolytes possessing excellent ionic conductivity at room temperature for high performance sodium ion batteries. Understanding the Na+ ion transport in these glasses is critical towards developing novel electrolytes for these all solid-state sodium batteries. In-situ characterization of Na+ ion transport through experiments is extremely challenging. Molecular dynamics (MD) simulations offer an economical route for investigating the local structure of these glasses as well as Na+ ion transport mechanisms. Classical MD simulations employ empirical forcefields to define pairwise interactions between constituent ions in these glasses. These empirical forcefields captures the short-range order accurately, but cannot capture the medium-range order. Additionally, these empirical forcefields are not to account for the complex chemistry in sulfide glasses makes it extremely challenging to model these glasses. While ab initio MD simulations are able to overcome these limitations, the maximum system size that can be realistically modeled using ab initio MD is limited (400-500 atoms) and cannot account for the bulk properties of these glasses.
Reactive force fields, such as ReaxFF, provide an effective route to accurately capture bond breakage and formation, while simulating considerably large systems (~ 100,000 atoms). These reactive force fields (ReaxFF) are based on bond-order formalism in conjunction with charge equilibration scheme. ReaxFF can more accurately capture the complex electrode-electrolyte interfacial reactions as compared to both classical and ab initio MD. Understanding these interfacial reactions is extremely crucial in developing a stable interface for high performance sodium ion batteries. ReaxFF forcefields are highly system specific and need to be parameterized for an individual system.
In the present study, we employed Monte Carlo Force Fields (MCFF) optimizer to parameterize ReaxFF for x Na2S – (1-x) SiS2 glasses. We utilized ReaxFF for Li/Al/Si/O as a starting forcefield which was expanded for the x Na2S – (1-x) SiS2 glasses. Parameterization was performed by fitting against formation energies, atomic configurations and charge distributions for a range of representative clusters and equations of state obtained through DFT calculations. The parameterized reactive forcefields were validated by comparing the pair distribution functions (PDF’s) obtained through MD simulations to those obtained through X-ray scattering experiments. Na+ ion transport was investigated in these glasses characterizing the changes in the local structure with composition. Interfacial reactions between pure sodium metal and glassy electrolyte were further analyzed using these parameterized forcefields.
Lithium Ion Batteries and Next Generation Energy Storage Technology - Adoption to Aircraft and Aerospace
Authors: Brewer Roger Alan 
Published: February 2020

Lithium ion batteries provide a high energy to weight ratio making the technology attractive for aircraft and aerospace applications. Introducing lithium ion battery technology, as with other types of battery chemistries, can prove challenging for a variety of reasons. As electrical load demands for aircraft increase controlling and harnessing high energy dense solutions will become more critical.
The presentation will begin with a basic introduction of lithium ion battery chemistry and evolve into a discussion on the role various aspects play in safely implementing lithium ion batteries on aircraft including the key design drivers and issues that influence system safety. The presentation will also cover key operational modes, applied to aircraft in general, that can drive risk and effect a prudent power system design (cell overheating, voltage “sag” below minimums at low temperatures, etc.) in the integration of battery technologies to an aircraft. Battery design features and attributes that relate to typical operating modes in an airborne platform will also be discussed in some detail.
The presentation will next evolve into a narrative on next generation energy storage technologies and supercapacitors (electric double layer devices) and their potential role in evolving airborne applications. Implementation of higher surge supportable energy storage designs, again driven by considerations at cold temperature conditions, will also be discussed. Energy and power density "road mapping targets" for evolving applications will be highlighted along with issues that influence nominal values including, but not limited to, operating temperature (cold and hot temperature extremes) typical of battery installations in harsher Aerospace environments. An illustration will be provided in the presentation of what the ideal aircraft battery looks like including the ability to float on an unregulated aircraft bus (without Batter Management Electronics) with large voltage swings, ripple content as well as other “nice to haves” (including higher packaged battery system Whrs and kilo-Watts per kilo gram than existing). A final summary will wrap up the discussion with an overview of the presentation material.
Modeling the Effect of the Operating Temperature on the Performance of a Zinc/Bromine Flow Battery
Authors: Lee Dongcheul , Koo Boram , Lee Jaewoo , Shin Chee Burm 
Published: February 2020

The zinc/bromine (Zn/Br2) flow battery is an attractive rechargeable system for energy storage because of its inherent chemical simplicity, high degree of electrochemical reversibility at the electrodes, good energy density, and abundant low-cost materials. Because the performance of a Zn/Br2 flow battery depends strongly on the operating temperature, it is important to develop a mathematical model to predict the performance of the battery as a function of the operating temperature in order to estimate such quantities as current efficiency and conversion per pass. This information can be used to design both of bench and production scale cells and to select the operating conditions for optimum performance.
In this work, a method of modeling the dependence of the charge and discharge curves of a Zn/Br2 flow battery on its operating temperature is presented. This work adopts a simple modeling approach by considering Ohm’s law and charge conservation on the electrodes based on the simplified polarization characteristics of the electrodes. To accommodate the temperature dependence, the key modeling parameters are expressed as the functions of temperature based on the well-known principles of the Arrhenius equation of chemical kinetics and the Nernst equation of electrochemical thermodynamics. The model is validated by comparing the modeling results with the experimental measurements.
Design of High Voltage All-Solid-State Batteries Based on Sulfide Electrolytes
Authors: Fitzhugh William , Li Xin 
Published: February 2020

Ceramic sulfide solid-electrolytes are amongst the most promising materials for enabling solid-state lithium ion batteries. With ionic conductivities that can meet or exceed liquid-electrolytes, such ceramic sulfides are limited in practice chiefly by a narrow electrochemical stability window of approximately 1.7-2.1 V vs Lithium metal. In addition, ceramic sulfides are frequently plagued by interfacial reactions when combined with common electrode active materials. In this talk, methods for the stabilization of both the bulk electrochemical decompositions and the interfacial reactions will be discussed. Solid-state cells stable up to 5V, including layered Li-Co-O and spinel Li-Mn-Ni-O, will be presented and the stabilization mechanisms will be discussed from a detailed theoretical perspective.
Ceramic sulfides are known substantially swell during electrochemical decay. Such swelling has been shown to provide a viable means by which to stabilize electrochemical decomposition in lithium ion batteries[1]. Evidence and theoretical understanding of stability window expansion as the result of mechanical constriction will be discussed for both Li10GeP2S12 and Li10SiP2S12 systems. Further discussion on the impact of interfaces will focus on our novel high-throughput computational schema[2], which has enabled the evaluation of nearly 70,000 material DFT calculation for interfacial stability with Li10SiP2S12. These new computational methods found over 2,000 high-voltage coating materials that are electrochemically inert against Li10SiP2S12 at standard cathode voltages.
The culmination of these approaches, mechanical bulk stabilization combined with interfacial coating layers, is the design of solid-state full cells with high voltage stability and good cyclability. The principal focus of this talk will be a discussion on the theoretical underpinnings of these methods and a comparison with experimental data.
[1] Fan Wu*, William Fitzhugh*, Luhan Ye, Jiaxin Ning, Xin Li. Advanced Sulfide Solid Electrolyte by Core-Shell Structural Design. Nature Communications, (9), 4037 (2018).
[2] William Fitzhugh*, Fan Wu*, Wenye Deng, Pengfei Qi, Luhan Ye, Xin Li. A High-Throughput Search for Functionally Stable Interfaces in Sulfide Solid-State Lithium Ion Conductors. Advanced Energy Materials. Under review.
Use of Polarization Curves to Determine Kinetics Parameters in K–O2 batteries
Authors: Gourdin Gerald , Xiao Neng , Wu Yiying 
Published: February 2020

Metal–O2 batteries have shown great potential as energy storage devices and are foreseen as one of the potential successors to lithium ion batteries. Unlike either batteries or fuel cells, however, metal-O2 batteries form an insoluble product that diminishes cathode capacity. Cathode capacity is related to the electrochemically-accessible surface area and product accumulation results in a loss of that surface area, which then contributes to the total overpotential during discharge. While typically used to determine the effect of varying load levels on the performance of energy producing devices (i.e. batteries, fuel cells), polarization, or current-potential, measurements are also an indirect measure of the different energy losses that contribute to the total overpotential associated with a particular redox process. Each region of the curve is affected by a specific overpotential that is dominant within a certain potential range. Polarization curves therefore allow for the determination of certain properties that are important for understanding and improving the performance of electrochemical energy devices.
As shown in Figure 1, the short steep, but curving, slope at the start of the current-potential curve is attributed to the activation overpotential, which is the energy required to overcome the potential barrier associated with the discharge reaction. The overpotential responsible for the long sloping line is attributed to the ohmic resistance, which is dominated by electrolyte resistance. Finally, the limiting current—sharp decline in the cell potential at higher current densities—is generally attributed to mass-transfer limitations. Using derived analytical expressions, essential kinetic parameters have been determined for fuel cells from the data obtained from polarization analyses.1,2

Proceeding from that previous work involving fuel cells, analytical expressions were derived that can be applied to the data obtained from polarization analyses of metal-O2 batteries. Due to the unique single-electron redox process (K+ + O2 + e− → KO2) in the cathode (oxygen) electrode, the K–O2 superoxide battery provided an ideal case for developing and evaluating those expressions.3,4 Polarization analyses were performed on K–O2 batteries and the data obtained was evaluated using the derived expressions to determine kinetic values essential to the operation and performance of the K–O2 battery.
References
1. A. A. Kulikovsky, J. Electrochem. Soc., 161, F263–F270 (2014).
2. J. Bockris and A. Reddy, in Modern Electrochemistry 2B - Electrodics in Chemistry, | John O'M. Bockris | Springer,, p. 1789–1901 (2000).
3. N. Xiao, X. Ren, W. D. McCulloch, G. Gourdin, and Y. Wu, Acc. Chem. Res., 51, 2335–2343 (2018).
4. W. D. McCulloch, N. Xiao, G. Gourdin, and Y. Wu, Chem-Eur J, 53, 3225 (2018).
Figure 1. Polarization Curve. Typical polarization curve from K–O2 battery

Figure 1
Synthesis of Nitrogen-Doped Molybdenum Sulphide and Molybdenum Sulphide/Oxide Nanocomposite As Active Materials for Supercapacitor Electrode
Authors: Kanade Chaitanya Kaluram , Kanade Vinit Kaluram , Hong Seokjun , Kim Taesung 
Published: February 2020

The layered transition metal dichalcogenide molybdenum disulphide (MoS2) is an excellent electrode material due to the presence of pseudocapacitance and electric double layer capacitance. However, low rate performance and capacity fading restrict its application in supercapacitor field. The doping and composite formation can tackle these problems easily. The nitrogen doping can increase the electrical conductivity of MoS2, which eventually enhances the supercapacitor performance while the formation of oxide and sulphide nanocomposite may increase the pseudocapacitance of the MoS2 materials. Thus, here we report the synthesis of nitrogen-doped MoS2 and MoO2/MoO3/MoS2 nanocomposite for application in supercapacitor electrode.
The nitrogen doped molybdenum sulphide and molybdenum sulphide/oxide nanocomposite were synthesised using hydrothermally synthesised MoS2 and urea as a nitrogen precursor in a tube furnace. The structural, as well as morphological characterisation, were done to confirm the synthesis of three-dimensional flowerlike MoS2 (Hexagonal) and nitrogen doped MoO2/MoO3/MoS2 nanocomposite using various spectroscopic and microscopic techniques. The X-ray diffraction (XRD) and selected area electron diffraction (SAED) pattern confirm the formation of mixed oxide and sulphide phases during the nitrogen doping process. The X-ray photoelectron spectroscopy (XPS) confirmed the nitrogen doping of the MoS2 nanostructures. Field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) were used to study surface morphology of synthesised MoS2 and nitrogen doped MoO2/MoO3/MoS2 nanocomposite. The FESEM and TEM show the flower-like morphology for sulphides and rod/plate-like structure for oxide phase of the nanocomposite. The electrochemical analysis were done to study the supercapacitor behaviour of synthesised materials. The electrochemical impedance measurements display increment in conductivity of MoS2 nanomaterials due to nitrogen doping. The highest specific capacitance observed for 1:1 (MoS2: Urea) weight ratio. The nitrogen doped MoS2 with mixed oxide and sulphide phases (MoO2/MoO3/MoS2) showed the nearly four times enhancement in specific capacitance (~129 F/g at 2A/g) than pristine hydrothermally synthesised MoS2 (~34 F/g at 2A/g). Overall, nitrogen doped MoO2/MoO3/MoS2 composite materials can likely to be used for application in supercapacitors.

Figure 1
High Capacity, Solid State Lithium Sulfur Battery with Ceramic Electrolytes
Authors: Choi Pyoungho , Svensen Alexander R , Sanghadasa Mohan 
Published: February 2020

Solid-state lithium-sulfur (Li-S) batteries with non-flammable, inorganic solid electrolyte can achieve a specific energy of 400 Wh/kg at low cost. The main technical challenges for this type of battery are i) developing a solid electrolyte that is highly conductive (>10-2 S/cm) with a large electrochemical window, ii) creating a large interface area in the cathode, and iii) ensuring low interface resistance between the electrolyte and electrodes. In addition, the solid electrolyte should be made thin but capable of being manufactured on a large scale.
New Li-S-Br-Si-Sn solid electrolytes have been prepared via ball-milling and heat treatment. The elemental composition and ball milling conditions (rpm, etc.) are optimized to get high ionic conductivity (>10-2 S/cm). Electrochemical stability window and ionic conductivity of the solid electrolytes are determined. All solid-state Li-S cells are fabricated by coating solid electrolyte on the cathode and attaching lithium on the electrolyte surface. Cathode is prepared by coating a slurry made of nanoscale sulfur, electron conductor (e.g., graphene), solid electrolyte, and binder on aluminum foil. A number of solvents and binders are investigated to form a homogeneous slurry with minimal agglomeration of particles like sulfur to generate high electrochemical interface area and desirable 3-D transport network for electrons and lithium ions.
The incorporation of binder in the solid electrolyte layer increases the electrochemical resistance of the layer. It is important to use a binder that offers a favorable trade off of lower resistance due to a thinner layer of solid electrolyte being possible and higher resistance due to the binder inhibiting transport of lithium ions. The composition, particle size, degree of compacting, thickness, and structure of cathode materials influence the transport of charge carrying species as well. The effect of binder on the resistance of solid electrolyte bulk and at the solid electrolyte-electrodes interfaces are characterized by AC impedance. Electrochemical performances of the solid-state Li-S cells will be presented. Some suggestions on developing solid electrolyte materials, manufacturing thin electrolyte film, designing the electrochemical interfaces, increasing sulfur loading in the cathode, and maintaining initial morphology of the cathode during the electrochemical processes will be discussed.