bluuebunny/crossref_metadata_2025 huggingface dataset:
(Digital Presentation) Microbial Fuel Cells: Electrochemical Property and Long-Term Stability Improvement
Authors: Houf William , Bashir Sajid , Liu Jingbo Louise
Published: July 2022

The microbial fuel cells (MFCs) are bioelectrochemical devices to convert chemical energy into electricity using a microorganism, without relying on abiotic catalysts and fossil fuels. The microbes enable proton production and electron transfer by oxidizing organic matters, which can be from wastewater, biomass, and other feedstocks. The electrons ﬂow will produce a direct electrical current, causing the potential diﬀerences between the anode and cathode compartments.

The aromatic sulfonation of membrane may result in acidity changes in the anode, causing microbe inhibitions. The PVA based novel membrane was developed and used as the electrolyte to overcome the above problems. The brewer’s yeast (S. cerevisiae) as a biocatalyst was used in MFCs due to the resilience to environmental changes and simple mechanism of electron transfer. The S. cerevisiae an eukaryote was found to easily retrofit into ethanol plants for in situ power generation, which were found improve the microbial fuel cell performance by our study.

This study indicated that anodic biofilm modification using nanoparticles is an effective approach to improve electrochemical activities due to their high surface area and high electronic conductivity. The red-light facilitates the efficient electron transfer through mediated redox couples within the anodic biota-anchored films. These redox mediators may represent an electronic network permeating the biofilm that can promote long-range electrical transfer in an energy-efficient manner, as a result of increasing MFC electricity production. As society migrates from consumption of gasoline to low carbon-based fuels, the MFCs becomes important to produce electrical energy with near zero net emission.

Figure 1
Poly(ethylene oxide)-Based Electrolytes for Solid-State Potassium Metal Batteries
Authors: Khudyshkina Anna D. , Morozova Polina A. , Butzelaar Andreas J. , Hoffmann Maxi , Wilhelm Manfred , Theato Patrick , Fedotov Stanislav S. , Jeschull Fabian
Published: July 2022

Most conventional batteries today employ organic liquid electrolytes (LEs) that are not only flammable, but also serve as a medium for irreversible side reactions at the electrode interfaces, especially when metal is used as electrode. In post-lithium systems, such as potassium batteries, this issue is even more pronounced due to a higher reactivity of the metal as compared to lithium, and typically results in electrochemical instability leading to a rapid capacity fade of the battery.[1] When switching from LEs to solid polymer electrolytes (SPEs) that typically show better electrochemical stability at low (< 0.5 V vs. K+/K) and high (> 4 V vs. K+/K) potentials due to polymers inherent inertness, enhanced cycle life of the battery is expected.[2] Moreover, well-known disadvantage of SPEs in Li-based batteries, i.e., poor ionic conductivity at ambient temperature, could be overcome in systems with larger cation size, e.g. K+
[3,4], potentially removing some of the bottlenecks previously encountered in the case of Li-transport.

In this presentation, a series of poly(ethylene oxide) - potassium bis(trifluoromethane sulfonyl)imide (PEO-KTFSI) compositions with different salt concentration was investigated for their potential application as SPEs in potassium metal batteries. To identify the most promising candidate in terms of ion transport and mechanical integrity, the effect of KTFSI concentration on thermal, rheological and electrochemical properties was studied. Several electrolyte compositions were examined in solid-state potassium batteries with a potassium metal negative electrode, and a positive electrode from Prussian blue analogue family. Our results reveal the advantages of solid-state systems with respect to improved capacity retention and Coulombic efficiency as compared to the reference system with carbonate-based LE, as demonstrated in Figure 1, thus paving the way for a new generation of potassium batteries with significantly improved key performance parameters.

Figure 1. Comparison of potassium half-cells employing different electrolyte systems: carbonate-based liquid electrolyte (LE) vs. PEO-based solid polymer electrolyte (SPE) (a) capacity retention and (b) corresponding Coulombic efficiencies.

[1] H. Wang, D. Zhai, F. Kang, Energy Environ.
Sci.
2020, 13, 4583–4608.

[2] J. Mindemark, M. J. Lacey, T. Bowden, D. Brandell, Prog. Polym. Sci.
2018, 81, 114–143.

[3] M. Perrier, S. Besner, C. Paquette, A. Vallée, S. Lascaud, J. Prud’homme, Electrochim. Acta
1995, 40, 2123–2129.

[4] U. Oteo, M. Martinez-Ibañez, I. Aldalur, E. Sanchez-Diez, J. Carrasco, M. Armand, H. Zhang, ChemElectroChem
2019, 6, 1019–1022.

Figure 1
(Digital Presentation) Pinpointing the Potential-of-Zero-Charge in a Alumina-Coated Aluminum/Water Interface Model for Corrosion Applications
Authors: Leung Kevin
Published: July 2022

The surfaces of most metals immersed in electrolytes feature a several nanometer-thick oxide/hydroxide layer in aqueous electrolytes. This leads to the existence of both a metal/oxide and an oxide/liquid electrotlyte interface. The resulting complexity, and the uncertainty about the structure of and the charges on the surface films, make it challenging to predict from first principles the potential-of-zero-charge (PZC) which has been correlated to the pitting potential [1]. In this work, we use large-scale Density Functional Theory and ab initio molecular dynamics to calculate the PZC of a Al(111)|gamma-Al(2)O(3)|water model within the context of aluminum corrosion. By partitioning the multiple, complex interfaces involved into binary components with additive contributions to the overall work function and voltage, we calculate the PZC in liquid water for this model. Simultaneously, we calculate the orbital energy levels of defects like oxygen vacancies in gamma-Al(2)O(3), which are critical parameters in theories associated with pitting corrosion onset. Our predictions align the Fermi level at PZC with oxygen vacancy impurity defect levels, and estimate the voltage needed to generate charged oxygen vacancies in the flat band approximation. The similarities and differences in results and assumptions used between our model calculations and experiments will be discussed.

[1] J.~O'M. Bockris and Y.~Kang, J. Solid Electrochem. 1:17 (1997).

Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the document do not necessarily represent the views of the U.S. Department of Energy or the United States Government.

Figure 1
Electrochemical Detection of Peroxynitrite Using Selenium-Decorated Graphene
Authors: Kalil Haitham , Ibrahim Magdy A , Curtis William , Bayachou Mekki
Published: July 2022

Peroxynitrite and other reactive oxygen species (ROS) have shown contribution to oxidative stress-driven diseases including cardiovascular dysfunction. A precise detection of these species in biological systems is not only crucial for understanding the genesis and progression of diseases, but also for developing and evaluating effective therapies. In the past decade, selenium attracted the attention of many researchers for its antioxidative applications. Research studies have found that selenium plays a key role in redox regulation as a ROS modulator and as a catalytic cofactor of endogenous antioxidative systems.

Our research study revealed the advantages of preparing electrochemical depositions of selenium as sensitive interfaces for peroxynitrite detection and quantification. In this regard, we fabricated highly sensitive and selective electrochemical sensors from a solution contains selenium dioxide in acidic medium. A series of glassy carbon electrodes (GCEs) have been modified with selenium nanoparticles, while another series of GCEs were modified with selenium-decorated graphene nanostructures for comparison purposes. The morphology and surface chemistry of the selenium and selenium-decorated graphene nanostructures were characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX). The electrochemical catalytic activities of these platforms were measured using cyclic voltammetry and chronoamperometry. The particle size of the prepared interfaces was determined by microscopic imaging particle analysis.

It was shown that elemental selenium nanoparticles incorporated into graphene sheets enhanced the sensitivity toward peroxynitrite. Selenium tends to stimulate the current response to aliquots of peroxynitrite in solution. Additionally, it enabled the use of fewer positive potentials, resulting in better differentiation between peroxynitrite and other analytes that are sensitive to more positive potentials.
(Digital Presentation) 3D Printing and Laser for Fabrication and Interface Modification of Origami-Inspired Dielectric Elastomer Actuators
Authors: Sundriyal Poonam
Published: July 2022

The soft and flexible materials with shape and size adaption characteristics are gaining much attention for many applications, including wearable electronics, biomedical devices, microfluidic systems, tunable optics, soft robotics, and adaptive systems. Despite the several advancements in this area, the automated manufacturing and interface modification of these devices is still a major challenge. Here, we report 3D printing and laser for the rapid and scalable fabrication of dielectric elastomer actuators. The elastomer-based inks of dielectric matrix and electrodes were prepared with desirable rheology to obtain excellent print quality and required mechanical and electrical properties. This process can produce thin and ultrathin layers, porous structures, and interface modification of the device components. The device with printed elastomer patterns exhibited a breakdown strength of 40 V µm-1 at 8 % strain. The finite elemental simulation was also performed to determine the device performance under different strain conditions. The proposed technique is highly beneficial for improving the manufacturing and performance of dielectric elastomer actuators.
Practical Considerations in the Development of 3 and 15 Ah Rechargeable Lithium Pouch Cells
Authors: Crowther Owen
Published: July 2022

Commercially available Li-ion batteries using graphite or graphite-silicon blended anodes are currently approaching a cell level specific energy of 350 Wh kg−1. EaglePicher previously demonstrated a 2 Ah rechargeable pouch with a lithium metal anode that delivered 375 Wh kg−1 (Crowther, Owen. "Solving Barriers to Commercialization of Cells with Lithium Metal Anodes." 236th ECS Meeting (October 13-17, 2019). ECS, 2019). Further improvements to chemistry and cell design resulted in a 3 Ah pouch with longer cycle life and specific energies above 400 Wh kg−1 (Crowther, Owen. "Rechargeable Lithium Metal Pouch Cell Development." ECS Meeting Abstracts. No. 1. IOP Publishing, 2021). This paper will discuss several new areas that resulted in improved cell performance such as increasing the tab size, optimizing the electrolyte type and amount, and introducing excess lithium metal into the anode. Figure 1 demonstrates the rate capability of the cell with larger tabs to minimize the ohmic resistance. The cell with delivers ~425 Wh kg−1 at low rate and >300 Wh kg−1 at a 6.6C rate. The maximum continuous rate for the cell with the original tabs was 1C. Finally, the initial prototype performance of a 15 Ah rechargeable lithium pouch cell with a specific energy >500 Wh kg−1 will be highlighted.

Figure 1
(Invited) Realizing Narrow Bandwidth Visible Photoluminescence from Colloidal Silicon Quantum Dots
Authors: Veinot Jonathan
Published: July 2022

Quantum dot light-emitting diodes (QD-LEDs) are an attractive alternative to organic light-emitting diodes (OLEDs) that have attracted attention for next generation optoelectronic devices due to their high colour-saturated photoluminescence, processability, and stability. Existing QD-LEDs often employ toxic or rare metals (e.g., Cd, Pb, In, etc.). Although colloidal silicon quantum dots (SiQDs) are an attractive alternative because of their abundance, biocompatibility and tailorable surface chemistry, tuning their luminescence throughout the visible spectrum can be challenging. Furthermore, SiQD emission shows a comparatively wide bandwidth that is a consequence of the inherent properties of the Si band structure. As a result the narrowing SiQD luminescence is not readily achieved by straightforward size selection methods used for other quantum dots. One alternative approach is to prepare optical cavities that preferentially select specific emission wavelengths using optical structures. This presentation will outline our investigations targeted on realizing bright, high quantum yield, narrow bandwidth luminescence from SiQD-polymer hybrids.
(Invited) Understanding Perovskite Nanocrystal Growth Using in Situ Transient Absorption Spectroscopy
Authors: Wong Cathy Y.
Published: July 2022

Lead halide perovskite nanocrystals (NCs) are promising materials for light-emitting applications. These NCs exhibit high photoluminescence quantum yields, are tunable throughout the visible wavelength region by varying halide composition, and can be easily synthesized using low-cost solution-based methods at ambient conditions. It is important to understand the mechanism by which NCs grow and the impact of growth on the eventual photophysics of the NCs. In this work, we develop a new transient absorption spectrometer that can measure the excited state dynamics of NCs in situ, during their synthesis. We report on the evolving excited state properties of MAPbI3 and MAPbBr3 NCs during their nucleation and growth using a ligand-mediated synthesis in a non-polar solvent. New insights into the evolution of the NC surface during growth are provided by analyzing features in the transient spectra that originate from the Stark effect, caused by trapped carriers at the surface.
(Invited, Digital Presentation) Circularly Polarized Photoluminescence from Nanostructured Arrays of Light Emitters
Authors: Ferry Vivian
Published: July 2022

Metasurfaces offer compact routes to spatial and polarization control of luminescence from nearby emitters. The most common integration strategy is to coat a patterned metamaterial or metasurface with a film of light emitting material. For example, structures such as arrays of Au nanorods coated with achiral light emitters exhibit circularly polarized photoluminescence at specific outcoupled angles. However, the degree of circular polarization in these systems is limited to relatively low values, and does not coincide with the angles with high photoluminescence intensity.

This talk will discuss an alternative strategy, where the light emitters are patterned instead. We show that this structure offers several advantages: rather than averaging over the contributions of emitters in many different locations, this system exhibits highly directional photoluminescence with high degrees of circular polarization. Most importantly, the photoluminescence intensity is high at the same angles where the degree of circular polarization is high.

These patterned light-emitting nanostructures are formed using direct-write electron beam lithography on semiconductor nanocrystals. This versatile method is capable of forming structures with aspect ratios greater than 2 and feature sizes as small as 30 nm, photoluminescence is retained after patterning, and the system is robust to multiple patterning steps.
(Invited) Enhancement of Light Emission in Luminescent Structures within Nano-Arrays
Authors: Biswas Rana , Peer Akshit , Zhang Yu
Published: July 2022

Nanostructures can dramatically alter the light emission in luminescent structures by strongly altering the photonic densities of states at the location of the luminescent emitter. We describe and develop two complementary platforms that tailor luminescent emission through i) quantum dots in nanocup arrays and ii) corrugated nanoarrays in organic light-emitting structures.

We fabricated nanocup arrays with pitch ~750 nm by replica molding in polymer molds. A thin non-conformal gold film was sputter-deposited on the polymer film with angle-directed deposition. The gold film was continuous with a variation of spatial thickness, with the film being optically thin at the bottom of the nanocup [1]. Optical measurements revealed an extraordinary optical transmission (EOT) peak at a wavelength slightly smaller than the pitch. Although no holes were etched in the film the optically thin metal at the bottom allowed resonant light transmission. This is a simple pathway to fabricate large area (>cm2) nano-arrays with EOT without expensive lithography which limits such nano-arrays to very small areas. Quantum dots were embedded in these nanoarrays and revealed a marked reduction of photo-luminescence lifetime by ~4 compared to the control samples, when the emitting wavelength was tuned to the optical resonance of the nanoarray. Scattering matrix and FDTD simulations both show an enhancement of the field by a factor >100. The optically enhanced field in nanocups enhanced the spontaneous emission of embedded quantum dots. The simulated Purcell factor is enhanced by >80 at the bottom of the nanocup, and by a factor of 3-15 averaged over the nanocup height, in agreement with measured photoluminescence lifetimes that decreased by a factor of ~4 for a quantum dot ensemble.

We also study and simulate light emission from organic light emitting diodes (OLEDs) -where only 20% of the light is emitted to air and remainder (~80%) is trapped as internally waveguided modes and surface plasmon modes at the cathode-organic interface. We develop rigorous scattering matrix simulations [2] to demonstrate the emission of light can be increased by enhancement factors >3, when the OLEDs are integrated with periodic nanoarrays. The emissive region conformally follows the periodicity of the nano-array. The periodic nanostructures diffract trapped waveguided modes and plasmonic modes to the air cone and are a pathway to achieving light outcoupling efficiencies exceeding 60%. The predicted dependence of the outcoupled light emission on the pitch and height of the nano-arrays will be presented.

Acknowledgements: Partially supported by NSF grants CMMI-1265844 and CMMI-170648.

References:

[1] A. Peer and R. Biswas, Nanoscale
8, 4657 - 4666 (2016)

[2] Y. Zhang, R. Biswas, ACS Omega
6, 13, 9291–9301 (2021).

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(Invited) Biodegradable Organic Electronics: Degradation of Eumelanin Studied by Fluorescence Spectroscopy
Authors: Santato Clara
Published: July 2022

A paradigm shift in resource exploitation and e-waste management is needed to promote sustainability in electronics. Reusing and recycling electronic devices is not only environmentally desirable but also economically viable and increasingly socially acceptable. A promising route to alleviate the environmental footprint of electronics is based on the use of abundant materials, novel production schemes involving non-toxic materials (through green chemistry processes), and eco-design of devices that includes environmentally acceptable end-of-life scenarios. Within this context, we integrate biosourced electro- and photo-active organic electronic materials, such as melanin, indigo, tannin and lignin derivatives (some of these readily available from biomass feedstock, abundant in Canada) into electronic and energy storage devices, such as transistors and

batteries. Biosourced organic electronic materials can be biodegradable. As such, they offer the opportunity for an environmentally benign device end-of-life scenario (as opposed to the present accumulation of e-waste).

The melanin biopigment family serves as a prototypical environmentally benign class of materials for sustainable organic electronics and its powering elements. Among melanins, eumelanin is a brown-black type found in the human body, other mammals, reptiles, amphibians, and fishes as well as in invertebrates, such as cuttlefish and insects. Sepia Melanin (natural eumelanin) is a type of biosourced eumelanin extracted from the ink sac of cuttlefish. Synthetic eumelanin is commercially available (indicated here as Sigma eumelanin).

We recently reported on encouraging studies on the biodegradability of eumelanin in industrial compost conditions (Di Mauro, E., Rho, D. & Santato, C. Biodegradation of bio-sourced and synthetic organic electronic materials towards green organic electronics. Nature Communications, https://doi.org/10.1038/s41467-021-23227-4); unfortunately, we did not report on intermediates of the biodegradation process. Insight on intermediates is expected to bring about an increase of the mineralization rate of eumelanin. Here, we will discuss possible oxidative degradation pathways of the biopigment eumelanin tin industrial compost conditions hrough fluorescence spectroscopy. Indeed, literature reports that oxidized (by oxidative cleavage of the quinoid structure of the indole moiety), naturally occurring eumelanin can give a lipofuscin-like yellow fluorescence.
(Invited) Luminescent Lanthanide Doped Nanoparticles
Authors: Vetrone Fiorenzo
Published: July 2022

In the last decade, the field of lanthanide doped upconverting nanoparticles has vastly matured, progressing from the basic understanding of the photophysical properties governing their nanoscale luminescence, to their use in the study of a number of fundamental properties and ultimately to a plethora of applications, with considerable focus in biology and medicine. This interest stems primarily from the ability to stimulate these luminescent nanoparticles with near-infrared (NIR) light as well as their diverse emission wavelengths spanning the UV to the NIR. Therefore, with a single NIR excitation wavelength, it is possible to observe anti-Stokes emission, known as upconversion, or single photon (Stokes) NIR emission. Here, we present our work on the synthesis and surface functionalization of various NIR excited (and emitting) core/shell lanthanide doped nanostructures/nanoplatforms and demonstrate how their various emissions could be harnessed for applications in biology and nanomedicine. Moreover, we investigate how these functional nanoparticles could be rendered even more versatile through rational combination with other NIR excited optical nanostructures.
(Invited) Organic Dyes Derived from Molecules in Cacao Beans for Use in Lighting Applications
Authors: Luscombe Christine Keiko
Published: July 2022

LEDs are the foundation of lighting and display products surrounding us. While they have obtained great success in the commercial market, related research and development activities remain highly active aiming to enhance factors such as energy efficiency, stability, and environmental sustainability. Currently, commercial LED products are comprised of two key components: an indium gallium nitride e LED backlight with emission centered at 450 nm to cover the blue region of the visible spectrum, and powder inorganic phosphors on top converting blue light into longer wavelengths (e.g., green and red) to tune the emission of the device. A drawback of inorganic phosphors is that scattering of the emission from the micron-sized phosphor powders leads to substantial backscattering and subsequent absorption of the emission into the LED chip, and reabsorption losses in the phosphor itself, both of which reduce the overall light output of the final LED device. Organic dyes possess environmental advantages over inorganic phosphors because they are pi-conjugated molecules made from abundant elements (C, H, N, O, etc.) and are potentially bio-sourced. In this talk, I will present dyes that have been developed from theobromine, derived from cacao beans. When blended within an industrial polymer, poly(styrene-butadiene-styrene) (SBS), their enhanced solubility enables the formation of highly transparent films, crucial for reducing scattering loss in LEDs. Furthermore, resultant dye-SBS films achieved photoluminescence quantum yields (PLQYs) of around 90% under ambient conditions. Taking advantage of their transparency and solution processability, we fabricated a waveguide with this theobromine-dye-SBS composite, which was subsequentially assembled into an edge-lit LED device of no glare and enhanced aesthetics.
(Invited) Advanced Electrolytes for High-Performance Lithium Metal Batteries
Authors: Thangadurai Venkataraman
Published: July 2022

The success of rechargeable lithium-ion batteries (LIBs) has brought evident convenience to human society, but state-of-the-art LIBs with a graphite anode are approaching their energy density limits. Li metal is considered the ultimate anode material due to its ultra-high theoretical specific capacity of 3860 mAh g-1, which is more than 10 times higher than lithiated graphite. Nonetheless, Li metal anode suffers from poor safety and low cycling efficiency due to its high reactivity. Electrolytes that work with Li anode should possess excellent stability against Li metal or form a highly passivating interface. It is also critical to control the amount of Li in the cell, preferably having no excess Li at the anode side.1 In this presentation, next-generation electrolytes that enable such types of high-performance Li metal batteries will be discussed, including advanced liquid electrolytes,2 garnet-type ceramic electrolytes3–5 and hybrid electrolytes.6,7

References

C. Zhou, A. J. Samson, M. A. Garakani, and V. Thangadurai, J. Electrochem. Soc., 168, 060532 (2021).

C. Zhou et al., Energy Storage Mater., 42, 295–306 (2021) https://doi.org/10.1016/j.ensm.2021.07.043.

S. P. Kammampata, R. H. Basappa, T. Ito, H. Yamada, and V. Thangadurai, ACS Appl. Energy Mater., 2, 1765–1773 (2019).

S. P. Kammampata, H. Yamada, T. Ito, R. Paul, and V. Thangadurai, J. Mater. Chem. A, 8, 2581–2590 (2020).

C. Zhou, A. J. Samson, K. Hofstetter, and V. Thangadurai, Sustain. Energy Fuels, 2, 2165–2170 (2018).

S. Bag, C. Zhou, P. J. Kim, V. G. Pol, and V. Thangadurai, Energy Storage Mater., 24, 198–207 (2019) https://doi.org/10.1016/j.ensm.2019.08.019.

C. Zhou, S. Bag, T. He, B. Lv, and V. Thangadurai, Appl. Mater. Today, 19, 100585 (2020) https://doi.org/10.1016/j.apmt.2020.100585.
Quantitative Evaluation of the Low Temperature Discharge Performance of Li-Ion Batteries Using Electrochemical Impedance Spectroscopy
Authors: Brown David Emory , McCloskey Bryan D.
Published: July 2022

To promote further adoption of electric vehicles (EVs)—as well as to improve the performance of other battery-powered technologies such as phones, laptops, and drones—Li-ion battery (LIB) low temperature performance needs to be significantly improved. At temperatures below 0oC, LIB discharge performance drops drastically below room temperature performance; for example, at -20oC, the LIB C/3 discharge capacity is less than 70% of its 30oC capacity. Significant research efforts are underway to quantify the dominant loss processes in LIBs discharged at low temperatures.

In this work, we use operando impedance spectroscopy during LIB discharge to quantify loss processes and to inform rational electrode and electrolyte engineering to maximize low temperature performance. We show that the graphite charge transfer resistance is the dominant loss process at low temperatures. We also demonstrate that inclusion of 𝛾-butyrolactone (GBL), a low melting point solvent that has similar structure to ethylene carbonate (EC), into the electrolyte as a co-solvent with EC decreases the resistances at the NMC positive electrode during low temperature operation, but it leads to substantial resistance increases at the graphite negative electrode when compared to a similar electrolyte with no GBL added. We discuss physical explanations for these resistance behaviors. Lastly, we use impedance spectroscopy to develop a coupled ion-electron transfer kinetic model to quantifiably compare the low temperature performance of different LIB chemistries. These findings will enable the development of significantly improved LIB discharge performance at low temperatures, paving the way for wider use and adoption of important LIB-powered devices, such as EVs.
Local-Structure Analysis of Li Oxy-Sulfide Glass-Ceramic Solid Electrolytes
Authors: Zimmermanns Ramon , Luo Xianlin , Knapp Michael , Hansen Anna-Lena , Indris Sylvio , Ehrenberg Helmut
Published: July 2022

In the global quest to tackle climate change and the promotion of sustainable energy sources, energy storage has become an important aspect and consequently has attracted great research attention. Solid state batteries promise increased energy density and safety in comparison to current commercial Li-ion batteries[1]. Fast ion conducting solid electrolyte materials are an essential part of solid-state batteries. The study of suitable materials and the understanding of the conduction mechanisms is therefore of high importance.

Sulfide and thiophosphate glasses have been identified as promising candidates as fast ion conducting materials and great progress has been made since the first studies in 1980[2]. One drawback of these materials is their sensitivity against humidity and instability on exposure to air. Recently, it was demonstrated that the doping of thiophosphate glasses with oxygen has a positive effect on the ion conductivity[2]. Furthermore, an improvement of the chemical and physical stability of these doped glasses could be achieved. The combination of these two effects renders oxygen doping a promising strategy. However, very little is known so far about the local structure of the doped glasses and glass ceramics, yet this information is crucial to enable purposeful development and further improvement of these materials.

Hence, we have studied the local structure of oxy-sulfide glasses as well as their structural evolution and crystallization behavior with increasing temperature. Additionally, the influence of the starting materials was evaluated by comparing materials from two different set of starting materials using the same synthesis route. Oxy-sulfide glasses of the composition Li3POxS4-x with 0 ≤ x ≤ 1.2 were synthesized by ball milling appropriate amounts of either Li2O, Li2S and P2S5, or Li3PS4 and Li3PO4. Temperature dependent x-ray powder diffraction and pair distribution function (PDF) analysis, supported by Raman spectroscopy and other characterization techniques, was then used to identify crystal phases and structural moieties. Subsequently, impedance measurements were carried out to be able to link microstructure to ionic conductivity.

[1] Tan, D.H.S., Banerjee, A., Chen, Z. et al. From nanoscale interface characterization to sustainable energy storage using all-solid-state batteries. Nat. Nanotechnol. 15, 170–180 (2020). https://doi.org/10.1038/s41565-020-0657-x

[2] Martin, S.W. Chapter 14: Glass and Glass-Ceramic Sulfide and Oxy-Sulfide Solid Electrolytes. Handbook of Solid State Batteries, pp. 433-501 (2015) https://doi.org/10.1142/9789814651905_0014

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Pseudo-Two-Dimensional Modeling of Lithium-Ion Conversion Cathode Materials
Authors: Horner Jeffrey Scott , Whang Grace , Kolesnichenko Igor V. , Dunn Bruce S. , Lambert Timothy N. , Roberts Scott A.
Published: July 2022

Conversion cathode materials are an intriguing next-generation chemistry for lithium-ion batteries due to their high theoretical capacity. Nevertheless, there are various practical issues inhibiting current use in consumer products including limited rechargeability due to capacity fade and poor performance at fast cycling rates. Partially responsible for these issues is the current lack of understanding of leading loss mechanisms for conversion cathode materials as the changing composition of the electrode makes it difficult to isolate and eradicate cell limitations. Electrochemical models are typically used in combination with experiments to improve understanding of cell performance and limitations. However, in comparison to intercalation cathode materials, fewer modeling studies have been conducted for conversion cathode materials. As such, a robust and efficient model for lithium-ion conversion cathode electrochemistry is desirable to optimize these materials for practical use.

Here, we present a pseudo-two-dimensional model for conversion cathode materials implemented using the open-source Python Battery Mathematical Modelling (PyBaMM) software. We apply the model to FeS2 – an intriguing material due to its abundance and high theoretical capacity. Upon discharge, FeS2 first undergoes an intercalation reaction followed by a conversion reaction with lithium to produce Li2S and Fe. The model is based on a polydisperse, core-shell approach for active material particles where the intercalated FeS2 core converts to a shell of Li2S, and two distinct sources for the current associated with the two separate reactions are enabled at the reaction surface. Upon initiation of the conversion reaction, an additional parameter representing the thickness of the converted shell material is tracked and used to incorporate ionic and electronic transport losses through this material. By comparing the model with experimental discharge data, we identify the leading loss mechanisms as poor solid-state diffusion during the intercalation reaction and poor electronic conductivity through the converted shell during the conversion reaction. Our analysis helps to guide design and optimization of FeS2 cathodes, and the adaptability the model encourages its use for other conversion cathode materials.

Supported by the Laboratory Directed Research and Development program at Sandia National Laboratories, a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525.
Extraction of Electrochemical Impedance Spectra from Physical Models
Authors: Kee Robert J. , Evans Tyler A. P. , Hoffman Robert M. , Zhu Huayang , Gerbig Felix , Vincent Tyrone
Published: July 2022

Electrochemical impedance spectroscopy (EIS) is used widely to assist the understanding and interpretation of electrochemical cells, including batteries, fuel cells, electrolyzers, etc. The measured spectra, often illustrated in terms of Nyquist plots, are typically interpreted in terms of equivalent-circuit models. The present approach is to interpret EIS using physical models. In principle, virtually any physical model that represents physics and chemistry in terms of conservation equations can be written abstractly as Eqs. 1-2, where x is the state
vector, u is the actuation
vector, yis the observable
vector, and p is the physical
param
eter
vector. The model can be represented in locally linear state-space form as Eqs. 3-4, where the Jacobian matrices A, B, C, and Dcan be established from local linearization as Eq. 5. The present paper compares two approaches to determine the state-space matrices. Assuming one has access to the physical model’s source code, the matrices can be evaluated by direct computational differentiation. Alternatively, the matrices can be evaluated using Pseudo Random Binary Sequence (PRBS) perturbations. With these matrices in hand, using the Laplace transform between actuation to observable, the complex impedance (i.e., real and imaginary parts of the impedance at frequency ω) can be evaluated as Eq. 6, where I is the identity matrix. By extracting the EIS from a physical model, the relationships between measurable parameters, such as cell dimensions, ion mobilities, etc., and the complex impedance can be established. These relationships are much more physically meaningful than those that can be inferred from equivalent-circuit models. The presentation includes examples of EIS derived from pseudo-two-dimensional (P2D) Li-ion battery models.

Figure 1
Theoretical Prediction of Freezing Point Depression of Lithium-Ion Battery Electrolytes
Authors: Self Julian , Bergstrom Helen K. , Fong Kara D. , McCloskey Bryan D. , Persson Kristin A.
Published: July 2022

Understanding and predicting the freezing point depression of liquid electrolytes is of interest particularly for low-temperature battery applications. We will present a computational methodology to calculate activity coefficients and the freezing point depression of liquid electrolytes relevant to Li-ion batteries. Theoretical expressions for Born solvation, Debye-Huckel ion atmosphere effects and solvent entropy are used with results from classical molecular dynamics simulations and electronic structure methods to calculate the activity coefficients of liquid electrolytes. Using the calculated activity coefficients as well as neat solvent properties, liquidus lines of the studied electrolytes are obtained up to 1 molal. The liquid electrolytes studied include LiPF6 in dimethyl carbonate and LiPF6 in propylene carbonate. It is found that the more significant freezing point depression of the propylene carbonate-based electrolyte versus dimethyl carbonate-based electrolyte originates in large part from the much higher dielectric constant of propylene carbonate versus dimethyl carbonate.
(Invited) Electrolyte Oxidation and the Role of Crossover Species in Capacity Loss for Lithium Ion Batteries
Authors: Lucht Brett L.
Published: July 2022

Cycling lithiated metal oxides to high potential (>4.5 V vs Li) is of significant interest for the next generation of lithium ion batteries. Cathodes cycled to high potential suffer from rapid capacity fade due to a combination of thickening of the anode solid electrolyte interphase (SEI) and impedance growth on the cathode. While transition metal catalyzed degradation of the anode SEI has been widely proposed as a primary source of capacity loss, we propose a related acid induced degradation of the anode SEI. A systematic investigation of LiMn2O4, LiNi0.5Mn1.5O4, LiNi0.6Mn0.2Co0.2O2, and LiNi0.8Mn0.1Co0.1O2 cathodes will be presented. The role of potential on the generation of soluble acidic fluorophosphates crossover species and the impact of these species on the structure and stability of the SEI will be presented.
Impact of Electrolyte Volume on the Cycling Performance and Impedance Growth of 18650 Li-Ion Cells
Authors: Bonakdarpour Arman , Stosevski Ivan , Smith Scott R. , Kelly Joel , Wood Bryan D. , Way Brian , Wilkinson David P.
Published: July 2022

The volume of electrolyte used in commercial cylindrical rechargeable Li-ion batteries needs to be closely controlled to optimize performance. It is widely reported in the open literature that insufficient electrolyte can negatively impact cycling performance. However, there are scant reports showing the impact of excessive amounts of electrolyte on cell performance. Here, we show that adding excessive amounts of electrolyte also negatively impacts the cycling performance, causing cells to show faster capacity fade. The effect can be quite significant, causing a noticeable difference within the first 30 cycles, particularly at higher discharge rates (e.g., 1C to 2C rates, Figure 1). It is important to understand the causes of this “high-volume effect” because it sets an additional constraint on the optimization of the system. We have carried out extensive electrochemical impedance measurements of commercial 3.5 Ah 18650 cylindrical cells with various levels of electrolyte (LiPF6/EC/DMC/EMC; 15/25/56/4 wt%) using PEIS and GEIS protocols at an ambient temperature of 25°C. The collected impedance patterns exhibit typical two loop features reported in the literature 1,2 and were modelled by a series combination of one resistance and two parallel R/C elements to extract the cell ohmic and charge transfer resistance values. The total cell resistance of cells with both nominal and high-volume electrolyte show impedance growth during cycling. However, the high-volume cell shows noticeably higher growth of charge transfer resistance. Details of the experimental work and possible mechanism of this effect will be discussed during the presentation.

References

N. Ogihara et al., J. Electrochem. Soc., 159, A1034–A1039 (2012).

W. Waag, S. Käbitz, and D. U. Sauer, Appl. Energy, 102, 885–897 (2013).

Figure 1
Analysis of the Interphase Formation of Thiophosphate Solid Electrolytes and the Lithium Metal Anode in Solid-State Batteries
Authors: Riegger Luise M. , Sann Joachim , Richter Felix H. , Janek Jürgen
Published: July 2022

Due to their high ionic conductivities and better safety, thiophosphate solid electrolytes (SEs) such as Li6PS5Cl or Li7SiPS8 are of interest for applications in solid-state batteries (SSBs). However, drawbacks such as their inherent reduction instability, which impede their application with a lithium metal anode (LMA) [1] as well as low gravimetric and volumetric energy densities of the resulting full cells [2] still have to be overcome.

If the decomposition products of SEs formed upon contact with lithium metal are sufficiently electronically conductive, the decomposition layer forms a so-called mixed conducting interphase (MCI). A (semi)metal dispersed in the MCI should decrease the internal resistance and lead to short circuits [3]. However, this is not the case for all metal ion containing SEs [4]. For example, the resistance of a Li|Li7SiPS8|Li symmetric cell constantly increases. Thus, knowledge about the composition of the interphase between lithium metal and SEs as well as the resistance evolution of a cell containing the respective SE is necessary.

We report our latest findings of the stability of several thiophosphate SEs in contact with lithium metal. We show the kinetics of the heterogeneous solid-state reaction and the chemical composition of the resulting interphase layer. Impedance spectroscopy measurements were conducted to investigate the temporal evolution of the interphase resistance between the lithium metal anode and the SE. In situ-sputter-deposition of lithium metal onto the surface of the SE pellets and subsequent X-ray photoelectron spectroscopy (XPS) measurements are performed to study the chemical composition upon contact. Multiple repetitions of these steps allow a detailed characterization and identification of the decomposition products within the forming interphase. The combined results of our studies allow us to distinguish between the possible interphases of metal ion containing electrolytes and promotes the understanding of the SE stability towards LMAs.

Reference
s
:

[1] X. Li, J. Liang, X. Yang, K. Adair, C. Wang, F. Zhao, X. Sun, Energy Environ. Sci. (2020) 10.1039/C9EE03828K.

[2] P. Braun, C. Uhlmann, M. Weiss, A. Weber, E. Ivers-Tiffée, J. Power Sources 393 (2018) 119-127.

[3] S. Wenzel, T. Leichtweiss, D. Krüger, J. Sann, J. Janek, Solid State Ion. 278 (2015) 98-105.

[4] L. Riegger, R. Schlem, J. Sann, W. Zier, J. Janek, Angew. Chem. (2020) 10.1002/ange.202015238.
Estimating Electrodeposition Properties and Processes: Cu-Ag Alloy at n-Si(001) and Ru Substrates from Acidic Sulfate Bath
Authors: Sun Yunkai , Shao Wenbo , Giurlani Walter , Innocenti Massimo , Zangari Giovanni
Published: July 2022

A simple method for estimating the composition and duration of the initial stage of alloy electrodeposition is important for deposition process design and the deposit characterization. Analytically or numerically solving the complete diffusion-migration-convection problem based on common simulation methods could be difficulty to be implicated as an ordinary task for designing alloy electrodeposition parameters and electrolytes.

In this work, we have proposed some simple estimations for the initial stage of Cu-Ag alloy electrodeposition, at Si(001) or polycrystalline Ru, regarding (1) the potential-composition curve, (2) the thickness of the initial deposit, and (3) the time interval to reach the steady state deposition, based on the stagnant diffusion layer model. The limiting deposition current is compared with the numerical results from Selman and Newman in 1970s [1]. Meanwhile, composition of the film deposited under limiting current with various electrolyte chemistries is compared with the model suggest by Brenner [2]. Despite the model proposed in this work are highly simplified and not precisely realistic, estimated values show good agreement with the observed values.

Reference:

[1] J.R. Selman, J. Newman, Migration in Supported Electrolyte Solutions with Free Convection, (1971).

[2] A. Brenner, 11 The Role of the Cathode Diffusion Layer in the Electrodeposition of Alloys, in: A. Brenner (Ed.) Electrodeposition of Alloys, Academic Press1963, pp. 307-330.

Disclaimer:

This work has been published at Electrochimica Acta, 403:139695 with title "Estimating electrodeposition properties and processes: Cu-Ag alloy at n-Si(001) and Ru substrates from acidic sulfate bath". Figure attached is chosen from this manuscript.

Figure (a) Observed and estimated composition-potential curve for Cu-Ag electrodeposition system. (b) Film thickness v.s. deposition time, and (c) film thickness v.s. composition of the film, from which Ag-rich initial deposit was observed.

Figure 1
High Nickel Positive Electrode Materials Modified By Dry Particle Fusion
Authors: Rathore Divya , Geng Chenxi , Hamam Ines , Zaker Nafiseh , Botton Gianluigi , Yang Chongyin , Dahn Jeff R.
Published: July 2022

High-energy-density Ni-rich cathode materials suffer from the critical challenge of poor capacity retention due to micro-cracking and interfacial reactivity with electrolyte. Addition of foreign elements to some Ni-rich materials is known to stabilize their capacity over cycling. In this work, we established that the benefit of these elements coating on Ni-rich hydroxide precursors before synthesis is universal in presence of major dopants used in Ni-rich materials in terms of improving the capacity retention of Co-free Ni-rich polycrystalline materials. Experimental characterization and theoretical modelling suggested some new perspectives on the location of these foreign elements along with their morphology control of primary particles and the working mechanism for superior performance.