bluuebunny/crossref_metadata_2025 huggingface dataset:
(Digital) Ionic Conduction Mechanism and Design of Metal–Organic Framework Based Quasi-Solid-State Electrolytes
Authors: Hou Tingzheng , Xu Wentao , Pei Xiaokun , Jiang Lu , Yaghi Omar M. , Persson Kristin A.
Published: November 2022

Recently, anionic metal–organic frameworks (MOFs) with superior ionic conductivity and Li+ transference numbers have opened a new avenue in the development of quasi-solid-state electrolytes (QSSEs). Given the superior performance and the characterization challenges associated with transport property measurements, it is vitally important to understand the Li+ transport and conduction mechanisms of this new prototype of QSSEs. In this presentation, we will discuss the theoretical and experimental investigation of two polyoxometalate (POM) -based MOFs, [(MnMo6)2(TFPM)]
imine
and [(AlMo6)2(TFPM)]
imine
, as QSSEs. Classical molecular dynamics coupled with quantum chemistry and grand canonical Monte Carlo are utilized to model the corresponding diffusion and ionic conduction in the two materials. Using different approximate levels of ion diffusion behavior, the primary ionic conduction mechanism was identified as solvent-assisted hopping (>77%), revealing the critical role of the solvent in MOF-based QSSEs. Detailed static and dynamic solvation structures were obtained to interpret Li+ motion with high spatial and temporal resolution. We found that the local charge distribution on POM surface largely determines the interaction between Li+ and the framework. Based on the prevalent mechanism of Li+ motion, we propose a hypothesized MOF design with a non-interpenetrating structure that is expected to achieve 6–8 times better ionic conduction performance (1.6–1.7 mS cm−1) than the current state-of-the-art (0.19–0.35 mS cm−1), approaching the conductivity range of liquid electrolytes.

Figure 1
Lithiation and Delithiation Behaviors of the Li-Cu Porous Anode in Li-Metal Battery System
Authors: Yang Seung Hoon , Choi Sanghyeon , Yoon Woo Young
Published: November 2022

The demand for High-energy-density batteries is rapidly increasing due to fast evolution of portable electronic devices, electric cars and energy storage systems. Lithium ion battery system based on graphite anode has made a lot of progress, however, it has almost reached its limit with the low theoretical capacity. Lithium metal anode has the advantages of high theoretical specific capacity (3860mAhg-1) and lowest electrochemical potential voltage (-3.04V vs standard hydrogen electrode). However, the commercialization of lithium metal is still hindered by several inherent challenges such as inhomogeneous lithium dendrites and huge volume expansion during deposition and dissolution. In this study, a use of the pore between Li and Cu powder for stable Li deposition without volume changes from commercially available cathode materials like NCM is investigated. In this system, binder-free anode is facilely and simply fabricated by pressing the well-mixed two powders of similar size. The effect of pore space created by adjusting the pressure on battery performance is verified. A utilization of Li powder induces controllable and uniform dendrite growth because the current density per unit area is lowered by increasing the specific surface area. Inert Cu powder not only leads to localize Lithium deposition, but also maintains a robust skeleton without volume changes. The lithiation and delithiation behavior of Li-Cu porous anode are thoroughly studied by material characterizations and electrochemical properties
Effect of Electrolyte on the Stress-Strain Behavior of Polymer Binder in Commercial Rechargeable Battery Electrode
Authors: Borges Martina , Pakhare Akshay , Nadimpalli Siva
Published: November 2022

Commercial battery electrodes are composites made of active particles bonded to current collected by polymer binders. Binder not only keeps all the particles together but also provides the electrical network necessary for battery operation. Several studies showed that the mechanical behavior of the polymer binder is very important, and it governs the cyclic performance of batteries. To develop advanced degradation models of battery electrodes, the mechanical behavior of binders needs to be characterized. Recently, some studies developed experimental methods to characterize the mechanical behavior of polymer binders, which showed that the most widely used binder, polyvinylidene fluoride (PVdF), behaves as an elastic-viscoplastic material under the typical charge/discharge rates of battery electrodes. However, the time dependent behavior of PVdF is not the only characteristic behavior to keep in mind. It should be noted that the electrolyte interacts with the binder and potentially changes its mechanical behavior which has not been characterized before. Most of the existing studies were carried out under dry conditions (no electrolyte present), and no study exists on the understanding of how electrolyte solvents and salts affect the mechanical behavior of polymer binders. In this talk, we will present the effect of electrolyte on the stress-strain behavior PVdF binder.
Electrochemical Characteristics of Pitch Coated Silicon/Graphite Anode Composites Using Surface Modification Process
Authors: Lee Jong Dae
Published: November 2022

The electrochemical characteristics of pitch coated graphite / silicon composites were investigated as anode material in lithium ion batteries. The anode materials were prepared with etched graphite using nickel chloride hexahydrate to create spherical pores on the graphite surface. The pore size was controlled depending on the calcination retention time and optimized for the insertion of silicon nanoparticles. Scanning electron microscopy, x-ray diffraction and thermogravimetric analysis were used to analyze the physical properties of pitch coated graphite / silicon composites. The electrochemical characteristics of the batteries were investigated by charge-discharge cycle, rate performance, cyclic voltammetry and electrochemical impedance spectroscopy tests in the eletrolyte of 1.0 M LiPF6 ( EC : DMC : DEC = 1 : 1 : 1 vol % ). Graphite/silicon/pitch electrode showed better electrochemical properties than the graphite electrode, and even nickel etched graphite was superior to graphite. Also, it was confirmed that both capacity and rate performance were significantly improved when the ratio of graphite, silicon, and pitch is 8 : 1 : 1 ( G8 Si1 P1 ). It is found that G8 Si1 P1 have the initial discharge capacity of 680 mAh / g, the capacity retention ratio of 90 % during 100 cycles and the retention rate capability of 91 % in 2 C / 0.1 C, 87 % in 5 C / 0.1 C.
Quinone-Based Redox Mechanism for Direct Recycling of End-of-Life Cathode Material
Authors: Kirwa Cyrus Kibichi , Coyle Jaclyn , Luo Hongmei
Published: November 2022

Redox chemistry mechanism method for direct recycling is explored in this work to relithiate End-of-Life (EoL) lithium-ion battery cathode material. Quinone-based redox mediators are used to restore lithium content in the EoL material. The redox mediator is reduced in the reaction and EoL is oxidized. These compounds can shuttle the charges very fast between lithium metal and the EoL. Electrochemical analysis and characterization of the relithiated cathode material are carried out to compare with the performance of pristine cathode material. This approach will potentially pave way for quality material recovery at a low cost. This project is part of ReCell which is a collaborative effort to develop efficient and economical recycle and reuse methods for EoL battery materials.
Electrode Design Strategies for High Energy Density All-Solid-State Li-S Batteries
Authors: Lee Jieun , Xu Guiliang
Published: November 2022

Sulfide solid electrolytes (SEs)-based all-solid-state battery (ASSB) has aroused enormous attention as to be a next-generation energy storage concept that offers enhanced safety. Particularly, the all-solid-state Li-S battery (ASSLSB) technology is the ultimate goal for ASSBs in regard to high energy density by adapting sulfur and Li metal as electrode materials. Herein, we propose the electrode design strategy for the sulfide-based ASSLSBs aiming for a super high energy density by novel synthesis method and precise composition optimization of the electrodes. To develop elaborate interfaces, all of the electrode and electrolyte particles were prepared with nanoscale dimensions. With careful adjustment of the electrode composition, the optimum value to deliver decent electrochemical performances was determined. The present study highlights the importance of electrode fabrication in electrochemical performance and provides insights into the electrode design to fulfill key requirements needed to be utilized in sulfide-based all-solid-state Li-S batteries.
Advancements in Polymer Blend Electrolytes for Lithium-Ion Conduction
Authors: Hallinan Daniel T. , Blatt Michael P. , Kim Kyoungmin , Nguyen Nam , Marxsen Stephanie F. , Smith Sage , Alamo Rufina G. , Kennemur Justin G.
Published: November 2022

Increasing the energy density of lithium-ion batteries requires, among other advances, electrolytes that are compatible with lithium metal and next-generation cathodes. Polymer electrolytes play an important role in this regard, but overcoming slow ion transport is a major challenge. Hybrid electrolytes that combine fast ion transport of ceramic electrolytes and processability of polymer electrolytes are promising. To take advantage of transport in both phases, transference numbers should be comparable. Thus, single-ion conducting polymer electrolytes have received major focus in recent years. In addition to the benefit in hybrid electrolytes, single-ion conduction yields numerous transport and efficiency advantages in neat polymer electrolytes. Due to formulation simplicity and motivated by block copolymer advancements, our team has focused on polymer blend electrolytes. State of the art in these electrolytes will be reviewed including recent advancements from our team using precision polyanions with polyether solvating polymer. This presentation will cover miscibility, conductivity, and transference numbers as a function of composition and temperature. Distinct differences between blends containing the different anionic forms will be explained in the context of ion correlation. Important future directions for the subfield of polymer blend electrolytes will also be discussed.
Understanding the Role of Al(TFSI)3 Additive at the Solid Electrolyte Interphase (SEI) for Improved Lithium-Ion Batteries with Silicon Anodes Via Solid-State NMR
Authors: Liu Haoyu , Park Sohyun , Dogan Fulya , Vaughey John T. , Key Baris
Published: November 2022

Introducing multivalent cation salts (e.g., Ca2+, Mg2+, and Al3+) has been proven to improve electrochemical performance such as capacity, cyclability, Coulombic efficiency, and calendar life of Si anode by the in situ formation of inert Li-Metal-Si ternary phases.1–3 Among these ions Al3+ is of great interest with large positive charge and small radius, providing potential new chemistry.

In this work, Al(TFSI)3 was synthesized and purified and 0.1 M was added as a second salt into the Gen2 (1.2 M LiPF6 in 30 wt % EC + 70 wt % EMC) electrolyte with 3 wt % FEC. Then NMC532/commercially relevant Si anode full-cells were assembled, stabilized with three formation cycles at a C/10 rate and divided into two groups, one with extended cycling and the other held at 4.1 V for one month to investigate calendar life. Meanwhile, non-Al(TFSI)3 cells were also prepared and tested from the same batch as baselines for the study. Multi-nuclei solid-state MAS-NMR including 1H, 7Li, 13C, 19F, 27Al, and 29Si of the Si powder collected from those samples after electrochemical testing at both 300 MHz and 500 MHz showed detailed information of different species formed. It was confirmed that Al additive stabilized Si species at the SEI and suppressed side reactions with the electrolyte by forming Li-Al-Si Zintl phase. Specifically, cross-polarization (CP) experiments such as 13C{1H} and 29Si{1H} allowed the selective investigation and detection of the species in close proximity to protons at the SEI. This additive strategy can be combined with the novel electrolyte, binder, and Si anode material to pave new avenues towards the commercialization of Si-based lithium-ion batteries.

Acknowledgement

This work was part of the Silicon Consortium Program (SCP) and was done at Argonne supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy under grant DE-AC02-06CH11357.

References

B. Han et al., ACS Appl. Mater. Interfaces, 11, 29780–29790 (2019).

X. Li et al., Chem. Mater., 33, 4960–4970 (2021).

Y. Zhang et al., Advanced Energy Materials, 11, 2101820 (2021).
Investigation of High-Performance All-Solid-State Lithium-Ion Batteries Based on High Ionic Conductivity Li7La3Zr2O12 Solid Electrolyte.
Authors: Hong Da-Been , Shim Jae-Hyun , Kim Yoo-Shin
Published: November 2022

As interest in battery safety is increasing in the battery industry, interest in all-solid-state lithium-ion batteries and their most important material, solid electrolytes, is increasing. Among all solid electrolytes, garnet-type Li7La3Zr2O12 (LLZO) has proven to be one of the most promising electrolytes due to its high Li ion conductivity, wide potential window and electrochemical stability to metallic lithium anodes. In particular, cubic garnet-type LLZO solid electrolytes are attracting a lot of attention in the development of all-solid-state batteries with high safety, high energy density and long cycles.

In this study, the optimal composition and sintering temperature were derived by adding Al, W, and Nb to synthesize a garnet-structured LLZO-based solid electrolyte powder and to form a stable cubic phase. In particular, Al, W, and Nb were doped to improve the ionic conductivity of the prepared LLZO-based solid electrolyte, and the ionic conductivity of the LLZO sintered body according to the doping composition and sintering process conditions was evaluated.
Comparative Evaluation of Polycrystalline and Monocrystalline LiNi0.96Mn0.02Co0.02O2 Cathodes
Authors: Kim Seokhun , Nagaraj Aditya , Min Sangkee , Shin Youngho
Published: November 2022

Lithium-ion batteries (LIBs) require Ni-rich cathode material with a high capacity to meet the growing demand for powering electric vehicles and other energy-dense devices. However, significant challenges remain to improve capacity retention during cycling and thermal-abuse tolerance of this material.

Alternative to the traditional polycrystalline Ni-rich cathode material, we report here a monocrystalline Ni-rich cathode material prepared via a hydrothermal process. Ni-rich composition (LiNi0.96Mn0.02Co0.02O2) was selected for comparative evaluation of polycrystalline cathode material via a co-precipitation process and monocrystalline cathode material via a hydrothermal process. A detailed description of the advanced CSTR co-precipitation process and the developed hydrothermal process applied to this material synthesis is presented.

The excellent physical and electrochemical properties of the monocrystalline cathode material prepared by the developed hydrothermal process will be reported through analysis of coin half-cell, SEM, EDS, ICP-MS, nanoindentation, and other advanced characterization techniques. This work underlines the developed hydrothermal process in producing monocrystalline cathode material which is a rapid, robust, and scalable process with economic feasibility.
Computational Investigation on Radiation Induced Thermal Runaway Propagation
Authors: Zhang Liwen , Chen Yi , Ge Haiwen , Zhao Peng
Published: November 2022

With the global trend of electrification and the fast expansion of electrical vehicle market, re-search and development of Li-ion battery as main energy storage medium has attracted extensive interest. One of the key issues that need to be resolved is thermal runaway and its propagation, where side reactions can occur when the battery is exposed to heat and other abuse conditions. Thermal runaway reactions are largely exothermic and can lead to subsequent fire and explosions when thermal runaway propagates to adjacent cells. In the current work, we focus on the effect of radiation on thermal runaway, which is especially relevant when a battery is exposed to adjacent heat and fire sources. To validate the numerical simulation, calculated radiation heat flux is compared with analytical solutions of radiation heat flux based on view factor expressions obtained in simple 2D cylinder-to-cylinder geometries. Very good agreement has justified the validity of the radiation calculation. Furthermore, radiation induced thermal runaway is evaluated between two cylindrical 18650 batteries. It has shown that depending on the temperature of the triggering cell, thermal runaway can either be triggered in the region close to the cell surface or internal domain within the cell, with different roles of the pre-runaway chemistry. Integrated radiation heat flux is calculated under a wide range of triggering temperatures, showing different limits under low and high temperature conditions. By analyzing the pre-runaway chemical heat release, it is further seen that radiation plays a dominant role under higher temperature conditions, while its significance gradually decreases under lower temperature conditions. Results from this work evaluate the role of radiation in thermal runaway propagation and provide useful insights into the thermal runaway control.
Cell-to-Cell Variation in Thermal Runaway Behavior
Authors: Zhang Liwen , Liu Lu , Zhao Peng
Published: November 2022

As one of the most promising energy storage mediums, Lithium-ion batteries (LIBs) have attracted extensive research interest. A major challenge associated with LIB application is thermal runaway, which can be triggered during overheating, overcharging, collision, and other abused conditions, leading to a direct threat to lives and properties. Here, we select Li-ion batteries with lithium cobalt oxide cathode and graphite anode (18650, Samsung), which are relatively simple and extensively investigated, to revisit thermal runaway. The experiment is conducted using an accelerating rate calorimeter (EV+ ARC, Thermal Hazard Technology) following the standard heat-wait-seek strategy, and is repeated for 9 similar new cells with 100% state of charge (SOC). Key features such as onset temperature of self-heating, the onset temperature of thermal runaway, maximum heat release rate, thermal runaway

delay time, and maximum temperature are measured experimentally. Although the cells are all brand new and have been initiated similarly, obvious cell-to-cell variability has been observed during thermal runaway. Major differences exhibit in the measured exothermic onset temperature, delay time, and mass losses; however, each cell nevertheless shows highly consistent activation energy processed from the heat release rate. Additionally, thermal runaway models are established in COMSOL to simulate the experimental conditions, with and without the effect of reactant consumption during the heating stage. It is shown that the widely used four-step thermal runway model cannot quantitatively capture the activation energy from the heat release rate. To improve the kinetic modeling and accommodate the cell-to-cell variability, statistical analysis is conducted to process the experimental results. Mean

and standard deviation of the frequency factor and activation energy has been acquired to determine the lower and upper bound of the kinetic modeling using a one-step global chemistry. The measured and simulated thermal runaway delay time has reached a reasonable agreement, with the uncertainty of the kinetic model considered. The identified cell-to-cell variability is most likely due to manufacturing inconsistencies, which should not only be considered for cell-level safety evaluation but also the design and evaluation of battery modules and packs.
(Digital Presentation) Particle Size and Transition-Metal Chemistry Determine the Impact of Li-Excess on Disordered Rock-Salt Li-Ion Cathode Materials
Authors: Lee Jinhyuk
Published: November 2022

The development of Co-free Li-excess disordered rock-salt (DRX) cathodes (e.g., Li1.2Mn0.4Ti0.4O2) for Li-ion batteries and interpretation through the percolation theory of Li diffusion have directed researchers to consider “Li-excess” (x > 1.1 in Li
x
TM
2-x
O
2
; TM = transition metal) as being essential to achieving high performance [1]. While the percolation theory provided an important insight into Li-transport in DRX materials, it leaves a critical impression that those DRXs without Li-excess will not deliver high capacity and thus are unsuitable as Li-ion cathode materials. However, the majority of DRX materials are made into pulverized nanoparticles whose small particle sizes (diameter < 150 nm) should render Li transport easy to achieve even with slow intrinsic Li diffusivity, making us question if Li-excess is necessary for designing DRX cathodes [2]. Moreover, the introduction of Li-excess requires a high degree of oxygen redox (along with TM-redox) in the materials to store electrons during cycling, leading to various O-redox-related side reactions (e.g., O-loss) that trigger fast capacity/voltage loss.

In this presentation, we show that Li-excess is not necessary for some DRX-cathodes demonstrated by Li1.05Mn0.90Nb0.05O2 (M90) and Li1.20Mn0.60Nb0.20O2 (M60), which both deliver high capacity (>250 mAh/g) regardless of their Li-excess level [3]. By contextualizing this finding within the broader space of DRX materials and confirming with DFT calculations, we reveal that the percolation effect is not crucial at the nanoparticle scale, which most DRX materials developed so far have assumed by having the pulverized nanoparticle morphology [2]. Instead, Li-excess is required to decrease the charging voltage of certain DRX cathodes, which otherwise would experience difficulties in charging due to their very high TM-redox potential. Our findings show the double roles of Li-excess – modifying the cathode voltage and improving Li diffusion – that must be simultaneously considered to understand the necessity of Li-excess for high-capacity DRX cathodes.

[1] J. Lee & G. Ceder et al., Science
343, 519-522 (2014)

[2] H. Li & J. Lee et al., Joule
6, 53-91 (2022)

[3] J. Lee & J. Li et al., Adv. Energy Mater., 2100204 (2021)
Ceramic/Polymer Hybrid Electrolyte with Enhanced Interfacial Contact for All-Solid-State Lithium Batteries
Authors: Ryu Kun , Lee Kyungbin , Ju Hyun , Park Jinho , Stern Ilan , Lee Seung Woo
Published: November 2022

All solid-state lithium batteries (ASSLBs) with a high energy density are challenging, yet desired by the rising energy demands. Its intrinsic safety of solid-state electrolytes (SSEs) compared to flammable liquid electrolytes makes ASSLBs a modern-day necessity. NASICON-type Li1.5Al0.5Ge1.5P3O12 (LAGP) has high ionic conductivity, high stability against air and water, and a wide electrochemical window. However, the application of LAGP is significantly hindered by its slow interfacial kinetics and brittle nature. In addition, the ionic conductivity of LAGP is relatively low at room temperature compared to that obtained at elevated temperatures. In our study, LAGP was incorporated into a polymer matrix to accelerate charge transport at the electrode-electrolyte interface to form LAGP-poly-DOL (LAGP-pDOL) hybrid electrolyte. The in-situ cationic ring-opening polymerization of DOL decreases the interfacial contact impedance and improves the mechanical properties of the SSE. LAGP-pDOL electrolyte exhibits prolonged cycle stability in symmetric cells (> 200 h) and in Li|LiFePO4 full cells (99% retention after 50 cycles) at room temperature. This study demonstrates the effective utilization of conductive polymer matrix into LAGP to enhance mechanical strength, interfacial contact, and room temperature electrochemical performance.
Preparation and Physicochemical Properties of Nanomaterial/Fullerene Composites
Authors: Imahori Hiroshi
Published: November 2022

Bismuthene, an exfoliated two-dimensional material obtained from bulk bismuth, has drawn significant attention because of its unique electronic properties. Few-layered bismuthene (FLBi) with an average thickness of 1.0 nm was synthesized by the ball mill and sonication method. The FLBi ﬁlm was fabricated onto a semiconducting SnO2 electrode by electrophoretic deposition (SnO2/FLBi). In the ﬂash-photolysis time-resolved microwave conductivity measurement, the SnO2/FLBi ﬁlm showed a rise of conductivity upon photoexcitation, supporting the occurrence of the electron injection from the photoexcited FLBi to the conduction band of SnO2. The SnO2/FLBi on a transparent ﬂuorine-doped tin oxide (FTO) electrode was used for photoelectrochemical devices. Photocurrents produced by the FTO/SnO2/FLBi electrode were larger than those produced by the FTO/SnO2 and FTO/FLBi electrodes because of the eﬃcient electron injection. Moreover, FLBi was noncovalently functionalized with fullerene C60 in a mixed solvent of toluene and acetonitrile. Upon photoexcitation, the composite of FLBi and C60 exclusively led to the occurrence of photoinduced energy transfer from C60 to FLBi without generating the charge-separated state. These results give fundamental insights into the feasibility toward the construction of FLBi-based optoelectronic devices.

Supramolecular composites consisting of fullerene C60 and carbon nanodiamond (ND) were prepared through spontaneous complexation of C60 aggregates onto the surface of ND aggregates in N-methylpyrrolidone. The resultant C60-ND composite was fabricated onto a nanostructured SnO2 electrode by an electrophoretic deposition method. Formation of the C60-ND composite was supported by dynamic light scattering and field-emission scanning electron microscopy. The C60-ND composite on the SnO2 electrode revealed high incident photon-to-current efficiencies in the visible region in comparison with the single component system of C60 or ND. The enhanced photocurrent generation of the C60-ND composite may originate from the photoinduced charge separation at the interface between C60 and ND. These results will give important insight into the design of all-nanocarbon optoelectronic devices.

[1] T. Umeyama, Y. Okawada, T. Ohara, and H. Imahori, Chem. Asian J., 14, 4042-4047 (2019).

[2] T. Umeyama, H. Xu, T. Ohara, Y. Tsutsui, S. Seki, H. Imahori, J. Phys. Chem. C, 125, 13954-13962 (2021).
Electrochemical Conversion of Natural Graphite into Carbon Nanostructures for Energy Storage Applications
Authors: Kamali Ali Reza
Published: November 2022

Natural graphite minerals with global reserves greater than 320 million tones can be considered as low-cost and highly available precursors for the preparation of high-quality carbon nanostructures with potential applications in energy devices and related areas. Here, the electrochemical conversion of natural graphite minerals into carbon nanostructures, comprising onion-like carbon nanoparticles and multiwall carbon nanotubes (MWCNTs) in high-temperature molten salts are studied. The galvanostatic polarization of electrodes made of such minerals is conducted in molten LiCl and LiCl-NaCl at various current densities, leading to the exfoliation of the minerals into carbon nanostructures. The influence of non-carbon impurities present in the natural graphite mineral, and the current density applied on the characteristics of the resultant nanocarbons are investigated. Moreover, the structural and microstructural properties of the nanocarbons fabricated using natural graphite minerals are compared with those produced using commercially pure graphite electrodes. It is found that the electrochemical nanostructuring of the mineral in molten salt not only increases the surface area of the material, but also increases its electrical conductivity. The high-yield conversion of the mineral into carbon nanostructures is realized at the cathode current density of around 1 A cm-2. The Li- and Na- ion storage performances of this sample are evaluated. The Li-ion storage capacity of the sample is found to be remarkable at around 460 mAh g-1 after 500 charge/discharge cycles at the current density of 200 mA g-1. The green molten salt preparation and the electrochemical performance of nanocarbons is discussed here.
Coal-Based Nanoporous Carbon Electrode for High-Performance Supercapacitor: Surface and Diffusion Charge Kinetics in Aqueous and Non-Aqueous Electrolytes
Authors: Abdulsalam Jibril , Bada Samson
Published: November 2022

South Africa generates around 60 million tonnes of coal discards each year, with over 1.2 billion tonnes landfilled in discard dumps and slurry ponds. The huge quantity of coal discards generated within the past decades, which is a significant liability to the mining industry and the environment, presents an opportunity to reuse this resource. This study investigated the potential of nanoporous carbon material from coal discard via KOH activation for use as electrode material in supercapacitors. Hierarchical morphology is seen via scanning electron microscopy (SEM). Raman spectroscopy reveals structural defects, X-ray Diffraction spectroscopy (XRD) confirms the material's amorphous nature, and N2 at 77k adsorption reveals a carbon material with high porosity and a surface area of 1424 m2/g.

Electrochemical analysis reveals that the charge storage mechanism of the material is surface-controlled (non-faradaic) in the non-aqueous (TEABF4/ACN) electrolyte and diffusion-controlled (faradaic) mechanism in the aqueous (Na2SO4) electrolyte. The material has a higher specific capacitance (162 F/g) and cycling stability of 87.1% capacitance retention after 5000 cycles in Na2SO4. The material exhibits a better rate capability in TEABF4/ACN with 92.3% capacitance retention. A symmetrical two-electrode device using Swagelok T-cell assembly achieves energy densities of 15.5 and 10.4 Wh/kg in Na2SO4 and TEABF4/ACN, respectively, and a power density of 100 W/kg in both electrolytes. The variation in the capacitive performance of the material in both electrolytes is due to differences in electrolyte ion size, ionic conductivity, and pore structure. This study not only establishes a link between the structure of coal-based nanoporous carbon and its electrochemical performance in both electrolytes but also demonstrates the potential of coal-based functional materials for sustainable energy storage.
Synthesis of Bimetallic MoS2/VS2 Nano-Urchins-Reduced Graphene Oxide Hybrid Nanocomposite for High Performance Supercapacitor Application
Authors: Bokhari Syeda Wishal , Wei Shanghai , Gao Wei
Published: November 2022

Two-dimensional (2-D) structure and high conductivity of the metal disulphides (MDs) are interesting for the applications in the energy storage sector. Nevertheless, their high instability restricts their widespread applications. In this work, we report MoS2/VS2 nano-urchins homogeneously grown onto reduced graphene oxide (rGO) matrix (denoted as G-MVS) via a facile hydrothermal approach and its electrochemical performance in an aqueous electrolyte system. G-MVS has a high specific capacitance of 460 F g−1 (287.5 F cm−2) at 0.5 A g−1 and 310 F g−1 (193.75 F cm−2) at 10 A g−1. In a symmetric configuration G-MVS//G-MVS, a high energy density of 49 Wh kg−1 (67.86 mWh cm−2) at a power density of 700.25 W kg−1 was achieved.
A New Method for Spectral Wavelength Selection Based on Multiple Linear Regression Combined with Ant Colony Optimization and Genetic Algorithm
Authors: Huang Qing , Xue Heru , Liu Jiangping , Jiang Xinhua
Published: November 2022

Wavelength selection is one of the key steps in quantitative spectral analysis, which reduces the computation time while also improving the prediction accuracy of the model. In this paper, we propose a wavelength selection algorithm based on the ant colony optimization (ACO), in which the absolute value of the regression coefficient of the multiple linear regression (MLR) model is used as the basis for evaluating the importance of wavelengths, and the absolute value of the regression coefficient after full wavelength MLR modeling is used as the initial pheromone value of the ant colony optimization (MLR-ACO). In each iteration, the absolute value of the regression coefficient corresponding to each wavelength of the individual with the highest fitness value is used as the basis for a pheromone update. The crossover operator is introduced in MLR-ACO (MLR-ACO-GA), and the individuals with the top 100 fitness values in MLR-ACO are used as the initial population of the genetic algorithm (GA). A selected frequency of wavelengths greater than the threshold among MLR-ACO individuals is calculated. A number of coarse interval points are generated according to the selected frequency, and a coarse crossover operation is performed at the coarse interval points. Fine crossover points are randomly generated within the coarse interval, and fine crossover operations are performed within the coarse interval to exploit the potential of combining excellent individuals in MLR-ACO with each other as much as possible. MLR-ACO can well solve the problem of traditional ACO initial pheromone scarcity, and MLR-ACO-GA can avoid MLR-ACO falling into a local optimum to a certain extent and be more flexible in the selection of the number of wavelengths, which can give full play to the advantages of MLR-ACO.
The Role of Alternative Splicing Factors hnRNP G and Fox-2 in the Progression and Prognosis of Esophageal Cancer
Authors: Zheng Yuanyuan , Niu Xiaoyu , Xue Wenhua , Li Lifeng , Geng Qishun , Fan Zhirui , Zhao Jie
Published: November 2022

Aim. Alternative splicing (AS) has been widely demonstrated in the occurrence and progression of many cancers. Nevertheless, the involvement of cancer-associated splicing factors in the development of esophageal carcinoma (ESCA) remains to be explored. Method. RNA-Seq data and the corresponding clinical information of the ESCA cohort were downloaded from The Cancer Genome Atlas database. Bioinformatics methods were used to further analyzed the differently expressed AS (DEAS) events and their splicing network. Kaplan–Meier, Cox regression, and unsupervised cluster analyses were used to assess the association between AS events and clinical characteristics of ESCA patients. The splicing factors screened out were verified in vitro at the cellular level. Results. A total of 50,342 AS events were identified, of which 3,988 were DEAS events and 46 of these were associated with overall survival (OS) of ESCA patients, with a 5-year OS rate of 0.941. By constructing a network of AS events with survival-related splicing factors, the AS factors related to prognosis can be further identified. In vitro experiments and database analysis confirmed that the high expression of hnRNP G in ESCA is related to the high invasion ability of ESCA cells and the poor prognosis of ESCA patients. In contrast, the low expression of fox-2 in esophageal cancer is related to a better prognosis. Conclusion. ESCA-associated AS factors hnRNP G and Fox-2 are of great value in deciphering the underlying mechanisms of AS in ESCA and providing clues for therapeutic goals for further validation.
Analysis of Cytokine Levels in Meibum and Clinical Correlations with Meibomian Gland Dysfunction
Authors: Liu Wenting , Lin Tong , Gong Lan
Published: November 2022

Objectives. This study is aimed at investigating the difference of meibum chemokines in MGD subjects with different degrees of MGD and the correlations of meibum chemokines with ocular surface parameters. Methods. Twenty MGD subjects (MQ

score
>
8

) and twenty MGD subjects (MQ

score
≤
8

) were enrolled to examine ocular surface parameters, including meibomian gland function (MGE, MQ meibograde, and lid margin), tear stability (NIKBUT, FBUT, and LLT), tear secretion (SIT and TMH), OSDI questionnaire, and CFS. These subjects also obtained meibum samples, and then meibum chemokines (MIG, IFN-γ, IL-8, IP-10, and MCP-1) were examined and analyzed the correlations with ocular surface parameters. Results. MIG, IP-10, and MCP-1 were found clearly elevated in MGD subjects with higher MQ score than that in MGD subjects with low MQ score (MIG:

p
=
0.038

, IP-10:

p
=
0.019

, MCP-1:

p
=
0.040

). The meibomian function was found mostly positively correlated with level of MIG (MGE:

r
=
0.600

,

p
<
0.001

; MQ:

r
=
0.579

,

p
<
0.001

) and IP-10 (MGE:

r
=
0.719

,

p
<
0.001

; MQ:

r
=
0.601

,

p
<
0.001

). The tear stability was found negatively correlated with the level of MIG (NIKBUT:

r
=
−
0.438

,

p
=
0.005

; LLT:

r
=
−
0.464

,

p
=
0.003

) and MCP-1 (NIKBUT:

r
=
−
0.425

,

p
=
0.006

; LLT:

r
=
−
0.761

,

p
<
0.001

). The OSDI was positively correlated with IL-8, IFN-γ, and MIG. Conclusion. Chemokines in meibum were significantly evaluated in MGD subjects suffering from severe meibomian gland quality. These findings indicate that chemokines play roles in the pathogenesis of MGD, and molecules targeted by chemokines may develop as novel agents for MGD therapy, perhaps through inhibiting inflammation in meibomian glands and microvascular in the eyelid margin.
Machine Learning for Diagnosis of Systemic Lupus Erythematosus: A Systematic Review and Meta-Analysis
Authors: Zhou Yuan , Wang Meng , Zhao Shasha , Yan Yan
Published: November 2022

Background. Application of machine learning (ML) for identification of systemic lupus erythematosus (SLE) has been recently drawing increasing attention, while there is still lack of evidence-based support. Methods. Systematic review and meta-analysis are conducted to evaluate its diagnostic accuracy and application prospect. PubMed, Embase, Cochrane Library, and Web of Science libraries are searched, in combination with manual searching and literature retrospection, for studies regarding machine learning for identifying SLE and neuropsychiatric systemic lupus erythematosus (NPSLE). Quality Assessment of Diagnostic Accuracy Studies (QUADA-2) is applied to assess the quality of included studies. Diagnostic accuracy of the SLE model and NPSLE model is assessed using the bivariate fixed-effect model, and the data are pooled. Summary receiver operator characteristic curve (SROC) is plotted, and area under the curve (AUC) is calculated. Results. Eighteen (18) studies are included, in which ten (10) focused on SLE and eight (8) on NPSLE. The AUC of SLE identification is 0.95, the sensitivity is 0.90, the specificity is 0.89, the PLR is 8.4, the NLR is 0.12, and the DOR is 73. AUC of NPSLE identification is 0.89, the sensitivity is 0.83, the specificity is 0.83, the PLR is 5.0, the NLR is 0.20, and the DOR is 25. Conclusion. Machine learning presented remarkable performance in identification of SLE and NPSLE. Based on the convenience for inclusion factor collection and non-invasiveness of detection, machine learning is expected to be widely applied in clinical practice to assist medical decision making.
Autonomous Braking System Using Linear Actuator
Authors: Vaibhav R. , Amutha Prabha N. , Indragandhi V. , Bharathidasan M. , Vasantharaj S. , Alaric J. Sam
Published: November 2022

The most frequent cause of vehicle accidents (car, bike, truck, etc.) is the unexpected existence of barriers while driving. An automated braking system will assist and minimize such collisions and save the driver and other people’s lives and have a substantial influence on driver safety and comfort. An autonomous braking system is a complicated mechatronic system that incorporates a front-mounted ultrasonic wave emitter capable of creating and transmitting ultrasonic waves. In addition, a front-mounted ultrasonic receiver is attached to gather ultrasonic wave signals that are reflected. The distance between the impediment and the vehicle is determined by the reflected wave. Then, a microprocessor is utilized to control the vehicle’s speed depending on the detected pulse information, which pushes the brake pedal and applies the vehicle’s brakes extremely hard for safety. For work-energy at surprise condition for velocity 20 km/hr, the braking distance is 17.69 m, and for velocity 50 km/hr, the braking distance is 73.14.
Determination of microscopic optical properties of agar and Zerdine phantoms at 635 nm using Kubelka-Munk function approach: A numerical study
Authors: Durmuş Hüseyin Okan , Seyidov MirHasan Yu
Published: November 2022

Since the precise and accurate determination of the optical properties of materials is very important for the development and application of optical technology, the investigation of the optical properties of biological tissues with tissue-like phantoms is an important research field in the applications of lasers in medicine. In this study, after directly determining the macroscopic optical properties of the agar and Zerdine phantoms at 635 nm, including the absorbance, transmittance, reflectance, refractive index, and total attenuation coefficient with the single integrating sphere test apparatus; the microscopic optical characterization of these two different soft tissue phantoms were realized at 635 nm by using the Kubelka-Munk function approach. For this, the microscopic optical parameters, which are the absorption coefficient, scattering coefficient, reduced scattering coefficient, and penetration depth, were calculated over these determined macroscopic optical properties.
A brief review on hardware structure of AC electric spring
Authors: Rokde Jyoti , Thosar Archana
Published: November 2022

Decarbonizing power generation and reducing greenhouse gas emissions require renewable energy sources. Intermittent nature of renewable energy sources can cause blackouts, fluctuation in voltage, grid-connected inverter usage, inability to predict power generation, fluctuations in voltage and frequency. It is possible to balance between the supply and demand of power to overcome these problems by using an electric spring (ES). It is necessary to study its work, types, and controlling actions for realizing the benefits of the electric spring. This paper reviews the hardware structure of an ES based on voltage-source inverter (VSI) and current-source inverter (CSI) topologies, in single-phase and three-phase AC power distribution systems with renewable energy sources. The structure, control strategies, operating modes, advantages and disadvantages of each ES topology are elaborated to make it a suitable alternative for resolving different power quality issues caused due to the high penetration of renewable energy sources.
DFT calculations of the main optical constants of the Cu2ZnSnSexS4-x system as high-efficiency potential candidates for solar cells
Authors: Nematov Dilshod
Published: November 2022

In the present work, using quantum-chemical calculations in the framework of density functional theory (DFT), we study the optical properties of semiconductor nanocrystals of kesterite Cu2ZnSnS4 doped with Se. Using the WIEN2k package, the concentration dependences of the optical characteristics of nanocrystals of the Cu2ZnSnSexS4-x system (x = 0, 1, 2, 3, 4) were calculated. It is shown that doping with Se at the S position leads to a noticeable improvement in the photo absorbing properties of these nanocrystals, as well as their photoconductivity in the IR range. The calculated absorption and extinction spectra of the materials under study, are compared with experimental data known from the literature. The data obtained will significantly enrich the existing knowledge about the materials under study and will help expand the scope of these compounds in optoelectronic devices, especially in solar cells and other devices that convert solar energy into electricity.
Power loss minimization assessment of a doubly fed induction generator with variable core resistance for wind turbines operation
Authors: Omeje Crescent Onyebuchi , Nnadi Damian Benneth
Published: November 2022

This paper assesses the efficiency level and power loss minimization of a doubly fed induction generator (DFIG). A modified DFIG equivalent circuit with multi-core resistance connected in parallel was adopted. State-space differential equations of the DFIG was developed incorporating iron and copper loss components while a minimum flux linkage that aids in the minimization of the overall losses was derived. Simulation results showed that losses were minimized when the equivalent core resistances were connected in parallel with minimum permissible current flow. The results obtained during a transient disturbance showed that at different core resistance values of Rfe = 0.75Ω and 0.25Ω, different efficiency values of 83.45% and 41.21% were realized. An unconstrained optimization test carried out on the DFIG variable parameters showed that the DFIG power loss model was controllable with a positive definite value of 691.9801 and 2.9156〖e〗^(+5) for the leading principal determinants of the Hessian matrix. All simulation processes were achieved in MATLAB/Simulink 2020.
ANFIS based AZSPWM methods for reduction common mode voltage in asynchronous motor drive
Authors: Lingangouda R. , Jyoti Pradeep B.
Published: November 2022

Space vector pulse width modulation (SVPWM) is a popular technique in the field of variable frequency induction motor drives. It gives better working and good direct current bus utilization in comparison to the sinusoidal PWM (SPWM) method. However, it decreases harmonic fluctuations and generates high common mode voltage (CMV) fluctuations, which results in common mode currents inside the motor. Hence, the performance of the motor may be deteriorated. To reduce the CMV, this paper presents a family of active zero state PWM (AZSPWM) methods using an adaptive neuro-fuzzy interference system (ANFIS). The proposed approach uses a five-layer hybrid learning algorithm for training the network. The training data is obtained from the classical SVPWM method. To analyze the proposed PWM methods, simulation is carried out using MATLAB and evaluated.
Competition and Productivity: Evidence from Peruvian Municipalities
Authors: Schiffbauer Marc , Sampi James , Coronado Javier
Published: November 2022

This paper uses new data on the removal of local, sector-specific barriers to firm entry across 1,800 municipalities in Peru to estimate the impact on firm productivity and markups. New legislation in 2013 strengthened the national competition authority's mandate to enforce the elimination of local entry barriers, providing a quasi-experimental setting to identify the impact of competition on productivity within the controlled institutional environment of a single country. We find that the elimination of local entry barriers boosted productivity, pointing to the critical role of subnational market entry barriers in explaining countries’ laggard productivity performances despite liberalized national regulatory environments.
Communicating through Defaults
Authors: Altmann Steffen , Falk Armin , Grunewald Andreas
Published: November 2022

We report the results of two laboratory experiments and a representative survey that investigate how default effects are shaped by information asymmetries and strategic incentives. We document that defaults are more informative when the interests of default setters and decision makers are more closely aligned. Decision makers’ propensity to accept defaults depends, both, on the alignment of interests and the quality of their information. In a second experiment, we demonstrate that decision makers are more likely to follow defaults than to accept (equally informative) advice. Complementary evidence from a representative survey underlines that consumers commonly perceive defaults as being set strategically.
Who Opts In? Composition Effects and Disappointment from Participation Payments
Authors: Ambuehl Sandro , Ockenfels Axel , Stewart Colin
Published: November 2022

Participation payments are used in many transactions about which people know little but can learn more: incentives for medical trial participation, signing bonuses for job applicants, or price rebates on consumer durables. Who opts into the transaction when given such incentives? We theoretically and experimentally identify a composition effect whereby incentives disproportionately increase participation among those for whom learning is harder. Moreover, these individuals use less information to decide whether to participate, which makes disappointment more likely. The learning-based composition effect is stronger in settings in which information acquisition is more difficult.