bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of Supercapacitor Performance Degradation Depending on Oxide Layer of Aluminum Current Collector
Authors: Kim Hyeonjin , Oh Mihyun , Yun Hyun , Shin Dalwoo 
Published: December 2020

Supercapacitor performance comparison depending on the various oxide film thickness of aluminum foil was studied. The study was focused on the anodic behavior of organic solvent based cylindrical supercapacitor.
The study aimed to see correlation between the active material current collector interface changes and the performance of the supercapacitor such as capacitance, ESR or gas generation depending on varying Al current collector oxidation pre-treatment. The results of performance test showed that electrode degradation of the interface between active material coating layer and the Al current collector are influenced by the oxidation pre-treatment process. Furthermore, the supercapacitor performance test by using long time period stored Al foil as a current collector (which is naturally oxidized at room temperature) was conducted to see how long the Al foil for supercapacitor can be stored without notable performance degradation.
Ternary Cross-Linked Multi-Functional Blended Polymers for High-Performance Silicon Anodes in Lithium-Ion Batteries
Authors: Attia Elhadi , Hassan Fathy , Elkamel Ali , Chen Zhongwei 
Published: December 2020

Silicon (Si) based anode material is highly attractive for next-generation lithium‐ion batteries (LIBs) due to its unparalleled
theoretical capacity and abundance. However, a severe problem of Si is the significant volume change associated with the
lithiation processes, resulting in reduced capacity retention. Researchers have traditionally considered the roles of
interactive binders and conductive additives as separate entities. These two components often lead to remarkably
decreased mass ratio of Si to nonactive material, which inevitably limits the electrode capacity. To achieve an enhance
utilization efficiency, herein, we have developed a multifunctional nanocomposite binder for high capacity nano-size Sibased
material through a cross-linked polymer of carboxymethylcellulose (CMC), polyacrylic acid (PAA) spine with
graphenized polyacrylonitrile (PAN) through a gradual carbonizing route. This nanocomposite strongly interacts with Si
material, providing a robust nanoarchitecture with abundant conductive pathways for Li-ion transport. CMC and PAA with a
large number of carboxyl groups provide binding ability by sturdy three-dimensional (3D) cross-linked network with relatively
a thin SiO2 mechanical binding film on the surface of Si nanoparticles onto a highly porous carbon and forming a stable
solid electrolyte interface (SEI) layer. Meanwhile, graphenized PAN provides a highly interconnected conductive
nanoarchitecture of a nitrogen-doped graphenized-like structure (NG), which provides enhanced pathways for lithium ion
diffusion. Without any conductive additives, this nanocomposite material not only shows a high superior 1st discharge
capacity of 3473 mAh g-1, high initial Coulombic efficiency of 89%, excellent rate capability, and remarkable cycling life for
more 600 cycles when cycled at high current density of 3000 mA g-1, but also maintaining good cyclability with a constant
high areal capacity of ~ 2.7 mAh cm-2. Together with the ease of fabrication, this provides a promising avenue for
commercial LIBs.

Figure 1
Prussian Blue Derived Vertical Graphene Structure for High Frequency Electrochemical Capacitors
Authors: Li Wenyue , Fan Zhaoyang 
Published: December 2020

High frequency electrochemical capacitors (HF-ECs), which have large capacitance density and therefore reduced device size in substitution of the bulky aluminum electrolytic capacitors, are of increasing interest. To produce HF-ECs that can respond at hundreds and even kilo hertz range, the tortuous mesoporous electrode of a conventional EC must be replaced with a relatively straightforward and large pore-based structure, and the whole electrode resistance must be small. Various electrode structures have been investigated but very few can deliver an adequate capacitance density at 120 Hz.
In this study, Prussian blue (PB) cubes, as a metal organic framework, are used as building blocks of a 3D scaffold for the vertical graphene (VG) nanosheets growth. In a rapid plasma enhanced chemical evaporation deposition (PECVD) process, a 3D conductive porous network comprised of VG and PB-derived carbon cages was successfully fabricated, and this material structure has a seamless interface with the current collector. Benefiting from the unique electrode material structure, the fabricated HF-ECs exhibited an equivalent series resistance (ESR)as low as 40 mΩ cm-2, 120 Hz phase angle (F

120
) of 85.9o and 120 Hz electrode areal capacitance (CA
120
) of 1.02 mF cm-2, or F

120
= -80.6o and CA
120
= 2.34 mF cm-2 for a thicker electrode, which are among the best reported overall performances thus far for HF-ECs. Integrated cell was assembled to work at 2.7 V for line frequency filtering of different waveforms, demonstrating excellent performance.

Figure 1. (a) SEM and (b) TEM images of PB derived vertical graphene structure. (c) CV curves recorded at 100 V s-1,(d) complex-plane-impedance plotswith inset displaying the high-frequency region, and (e) the derived specific capacitance versus frequency (red line: 3 mg, yellow line: 5 mg and purple line: 7 mg of PB precursor treated in PECVD for 5 min).

Figure 1
Using Scanning Micro X-Ray Fluorescence (µXRF) to Visualize, Understand and Quantify Transition Metal Dissolution in Li-Ion Cells
Authors: Eldesoky Ahmed , Logan Eric R. , Johnson Michel , McFarlane Chris , Dahn Jeff R. 
Published: December 2020

State-of-the-art Li-ion batteries (LIBs) typically consist of a graphite anode with a capacity of 372 mAh g-1 and a cathode material consisting of a layered transition metal oxide in the form of LiMO2
, where M = Ni, Mn, Co or Al (NMC and NCA material), or olivine-type material in the form of LMPO4
, where M = Fe, such as LiFePO4 (LFP). Proposed degradation mechanisms for the cathode material in LIBs include transition metal dissolution (TMD), particle cracking and phase transformation, which are believed to contribute to significant capacity fade due to the loss of cathode active material1.
Here, we report the use of scanning Micro X-Ray Fluorescence (µXRF) to investigate the effects of cell drying conditions and VC additive on the extent of TMD in LFP type cells and its subsequent deposition on the anode surface. For quantitative analysis, we prepared a calibration wedge made up of a pristine graphite anode with a known linear gradient of sputtered Fe. Figure 1a shows the µXRF images of the calibration sample and blank, from which we were able to correlate known TM concentrations to an observed signal intensity in the form of net count per area to facilitate accurate quantification, schematically shown in Fig. 1b. Unlike previous reports of XRF use in TMD analysis2, our approach allows us to quantify TM concentration deposited on our anodes without having to alter the surface by DMC washing, or through ball-milling, which preserves the nature of the sample and allows us to extract both quantitative and qualitative information (such as element distribution) from our aged cells using matrix-matched calibrants.
In this work, we demonstrate how our scanning µXRF approach enabled us to visualize the distribution of TMs and other elements present on the anode surface and quantify TMD in LFP Li-ion cells. We show that Fe dissolution can be greatly reduced with rigorous cell drying and appropriate choice of additives. Additionally, we report the presence of locally high TM concentration spots on the anode which we believe are due to non-uniformities in cell stack pressure. Finally, we observe that the extent of TMD is normally not significant enough to be responsible for cell capacity fade due to active material loss, and propose how Fe dissolution might be contributing to a more complicated cell failure mechanism which will be important to investigate in future work to understand its impact on cycle life.

References:

Börner, M. et al. Degradation effects on the surface of commercial LiNi0.5Co0.2Mn0.3O2 electrodes. J. Power Sources
335, 45–55 (2016).

Evertz, M., Lürenbaum, C., Vortmann, B., Winter, M. & Nowak, S. Development of a method for direct elemental analysis of lithium ion battery degradation products by means of total reflection X-ray fluorescence. Spectrochim. Acta - Part B At. Spectrosc.
112, 34–39 (2015).

Figure 1
Impact of Water on the Properties of Superconcentrated Electrolytes
Authors: Genereux Simon , Gariépy Valérie , Rochefort Dominic 
Published: December 2020

Superconcentrated electrolytes are a new class of electrolyte that is of interest to the scientific community for battery applications. These electrolytes consist of an amount of salt greater than the amount of solvent, while remaining liquid. It is currently accepted that the reduction of the solvation sphere under these conditions results in a greater electrochemical stability of the solvent and a higher Li+ transport number. These properties, are widely used in the literature For instance, superconcentrated electrolytes employing acetonitrile as the solvent have been applied in lithium metal batteries while acetonitrile with moderate salt concentration decomposes on lithium. Despite the attractiveness of the field to these electrolytes, their properties are still poorly understood, and the methods of analysis used vary between different studies. There is no standard protocol for their use and it becomes difficult to establish correlations between different studies. Our goal is to establish the required methods to standardize the methodology and fill the gaps in the field.
To do so, we firstly studied superconcentrated electrolytes based on LiTFSI and acetonitrile. The approach taken highlights the factors that have a significant impact on the properties of electrolytes. One of these factors is the water content. The results demonstrate that the presence of water in the solutions has a limited impact on the physical properties of viscosity and density of the mixtures as long at the concentration remains at and below 1000 ppm. The water content has a significant impact on the electrochemical window of stability of the electrolyte, reducing it to less than 2 V at 1000 ppm. The solvating structure of superconcentrated electrolytes is also studied via the electrochemistry of the Ferrocene/Ferrocenium couple to probe the impact of the electrolyte properties on electron transfer reactions. These results highlight the importance of structure and composition in the development of superconcentrated electrolytes.
Full Cell Understanding of Solvents in Battery Systems
Authors: Usrey Monica Lee , Guillot Sarah Lucienne , Johnson Tobias , Peña Hueso Adrián , Zhou Liu , Kerber Brian , Du Peng 
Published: December 2020

Lithium ion batteries are complex systems with multiple components that can be optimized to obtain desired performance capability. These components include electrolyte salts, solvents, and additives, as well as electrode active materials and coatings. Rational optimization of battery components requires an understanding of the fundamental science driving the observed performance. Silatronix® has developed a suite of analytical tools and methods using a combination of full format batteries, lab R&D cells, and model systems to construct a complete understanding of the battery from the cell level performance to the fundamental chemistry. This process includes the recovery and analysis of all parts of a full format pouch cell, including liquid electrolyte, generated gas, and electrode surface layers (Fig. 1).
Using this process, Silatronix® has evaluated several battery components, including organosilicon solvents for Li-ion electrolytes, to acquire a comprehensive picture of how these components provide observed performance benefits. For example, OS3®, a novel organosilicon chemistry that merges a silane with a Li+ coordinating nitrile functionality, has provided multiple performance benefits in various advanced Li-ion chemistries. Key experimental results include improved high temperature cycling stability in full format graphite/NMC622 pouch cells with 1%, 2%, or 3% OS3® (Fig. 2a), and using a model system of electrolyte in NMR tubes, we show that enhanced thermal stability of the bulk electrolyte results from HF scavenging and LiPF6 salt stabilization when 2-16% OS3® is present (Fig. 2b). Reduction of gas generation during high temperature testing in pouch cells with a commercial Si-based anode is also shown with 2% OS3® (Fig. 2c), and gas product identification and quantification is determined by GC-TCD for mechanistic analyses. In addition, OS materials change the reactivity of other electrolyte components, particularly at the electrolyte/electrode interfaces that govern critical performance attributes in Li-ion cells such as gas generation and interfacial impedance. These key performance benefits serve to enable several next generation battery chemistries, including a strong synergy with Si-based anodes.

Figure 1
Degradation of Carbon Electrodes in the Vanadium Redox Flow Battery
Authors: Singh Ashutosh Kumar , Pahlevaninezhad Maedeh , Yasri Nael , Roberts Edward P.L. 
Published: December 2020

The Vanadium Redox Flow Battery (VRFB) is a promising candidate for large scale energy storage. These systems are expected to operate for long cycle life ~ 10 years of lifetime (~ 500 - 2000 charge – discharge cycles).1 The VRFB’s system includes an posolyte (VO2
+/VO2+) and negolyte (V2+/V3+) compartments with carbon electrodes, and uses acidic electrolytes (usually 3M H2SO4). The carbon electrodes in VRFB need to perform in a harsh and corrosive environment associated with the charge/discharge cycling. In this study, we used polyacrylonitrile (PAN) based carbon papers as model carbon electrodes to study changes in the electrodes during cycling operation. The carbon papers were pre-treated according to the conventional approach by heating them in air at 500 ⁰C to incorporate oxygen functional groups on their surfaces.2,3 These pre-treated electrodes were then used in flow battery for 100-cycles at a current density of 80 mA/cm2. At the single cell level, the performance of these electrodes following the operation indicated a slight decrease in voltage efficiency (from 60 % to 52 %). This decrease in performance may be attributed to the electrode degradation during operation. Characterization of the electrode prior and following 100-cycles was performed using Raman spectroscopy, XPS analysis as well as electrochemical studies. Raman analysis showed differences between the fresh and the degraded carbon electrodes, including increasing defect and electronic density distribution. XPS analysis of the degraded electrodes suggest an alteration in the amount of oxygen functional groups. Electrochemical studies showed an decrease in the electron transfer kinetics after degradation, coupled with noticeable difference between the electrodes exposed to the posolyte (VO2
+/VO2+) and negolyte (V2+/V3+). The results provide insight into the stability of the oxygen functional groups during cycling operation which could assist in developing pre-treatment methods to functionalize the VRFB’s electrodes and for other similar electrochemical systems.

References:

(1) Soloveichik, G. L. Flow Batteries: Current Status and Trends. Chem. Rev.
2015, 115, 11533–11558.
(2) Singh, A.; Yasri, N.; Karan, K.; Roberts, E. P. L. Electrocatalytic Activity of Functionalized Carbon Paper Electrodes and Their Correlation to the Fermi Level Derived from Raman Spectra. ACS Appl. Energy Mater.
2019, acsaem.9b00180.
(3) Singh, A. K.; Yasri, N.; Karan, K.; Roberts, E. P. L. Effect of Pretreatment on Carbon Materials. Meeting. Abstract.
2018, MA2018-01, 2391.
Using Flow to Control Lithium-Ion Battery Crosstalk for Better Lifetime Predictions
Authors: Siboonruang Tana , Tang Maureen 
Published: December 2020

High-voltage lithium-ion batteries suffer from accelerated capacity fade due to crosstalk reactions between their electrodes. For example, while the battery is operating at a high voltage, transition metals from cathode active material dissolve into the electrolyte and diffuse to the anode. These metals disrupt the formation, growth, and performance of the solid-electrolyte interface (SEI), causing accelerated capacity fade. Although the effects of crosstalk reactions on battery lifetime and coulombic efficiency are well documented in full-cell studies, the mechanism by which accelerated capacity fade occurs is currently poorly understood.
In this study, we show that a combination of collector-generator experiments and single particle battery modeling can be used to better understand the effects and mechanisms of crosstalk reactions on capacity fade. Using a microfluidic flow cell, lined with commercial high-voltage lithium-ion battery electrodes and filled with commercial lithium-ion battery electrolyte, we are able to replicate commercial battery conditions while studying crosstalk reaction fundamentals. Because of forced convection in the cell, crosstalk species generated at the upstream electrode react at the downstream electrode and do not diffuse back to the upstream electrode. This allows us to isolate effects of crosstalk reactions on the downstream electrode and more clearly determine their role in capacity fade.
From this study, we present a series of proof-of-concept experiments, in which we show that the charge/discharge behavior of each electrode will clearly depend on flow rate and direction. In addition, we also demonstrate that, using electroanalytical techniques, crosstalk reaction thermodynamic and kinetic parameters can be determined. These parameters are then implemented into a single particle model to elucidate the effects of crosstalk on battery lifetime. This application highlights the novelty of the microfluidic flow cell in deconvoluting crosstalk reactions for generating meaningful inputs in physics-based battery lifetime models.
Scaling While Shorting: Lessons Learned When Non-Unity Coulombic Efficiency Is Independent of Cycle Life
Authors: Steingart Daniel A. , La O' Gj , Mohr Robert 
Published: December 2020

The modern lithium ion battery has been engineered to impressive standards, with coulomibic efficiency approaching 99.999% and a safety record for well manufactured cells of less that on incident in 10,000,000 cell given the correct environmental and cycling standards. But the ion-shuttle mechanism within the the battery sets up the relationship
Cremaining
= Cinitial ηc
cycles

Over the past few years we have redesigned a zinc bromine battery that decouples this relationship almost completely, with the goal of
Cremaining
≠ Cinitial ηc
cycles

In this approach we purposefully trade entropy management for cycle life, but it is not without its cost and challenges. In this presentation I will review the progress and challenges of a battery that does not fail critically under internal short circuit conditions, and discuss pathways and pitfalls we have discovered along the way.
We will discuss:

The extent to which side reactions can be "self-cancelling"

The associated impact of heat generated by "guided" side reaction

The scaling behavior and functional and spatial heterogeneity encountered when one allows significant latitude in the reaction space within a cell.
(Invited) Zombie Lithium: Consequences of Remainder Lithium Metal in Lithium Ion Batteries
Authors: Steingart Daniel A. , Chang Wesley 
Published: December 2020

It is well understood that lithium metal should not exist in lithium ion batteries, but high energy/high rate lithium ion cells did not seem to have gotten this memorandum. Dissection of commercial cells often indicates direct and indirect evidence of metallic lithium present in the battery. This lithium is often called "dead" lithium as it is considered no longer active. In this presentation we motivate the nomenclature zombie lithium because it is, in this construction, truly undead. Lithium metal that is present in lithium ion batteries is never completely isolated from the other activities of the cell, and as the cell ages, without proper understanding, the "dead" lithium can suddenly arise and impact the cell is decidedly negative ways.
In this presentation we will review and (try to) understand behavior of zombie lithium generated during the operation of a lithium ion battery and time scale and length scales of its impact across the cell and the system.
Gelation of Cathode Electrolytes for Improved Structural Integrity and Enhanced Electrochemical Performance of Li-O2 Batteries
Authors: Tamate Ryota , Matsuda Shoichi 
Published: December 2020

Due to the significantly high theoretical energy density, lithium-oxygen (Li-O2) batteries have been attracting much attention as next generation lithium secondary batteries. Nevertheless, there remain a lot of fundamental challenges to be solved for commercialization of Li-O2 batteries, and the cycling performance of currently reported state-of-the-art Li-O2 batteries is still very poor compared to commercially available Li-ion batteries.[1,2] One of the critical problems for the Li-O2 batteries is the leakage of excess liquid electrolytes from the cathode.[3] During the cell operation, Li2O2 is deposited onto the surface of carbon electrodes, which forces the liquid electrolyte out of the cathode. As a result, the deficiency of liquid electrolytes induces deterioration of the cycling performance. Moreover, the formation of Li2O2 causes serious volume expansion of the carbon cathode, which leads to the structural disintegration of electrodes.[4]

To suppress the leakage of electrolytes and disintegration of cathode structures, we are aiming to gelate electrolytes inside the carbon nanotube (CNT) cathodes. Although some gel polymer electrolytes have been reported for Li-O2 batteries so far,[5] gelation of electrolytes inside the cathode has been little investigated. In this study, several types of multi-functional cross-linkers are evaluated to gelate the cathode electrolytes via thermally or UV light-initiated in situ polymerization. By tuning the chemical structure and composition of gelling agents, viscoelastic properties of gels can be broadly controlled. We investigate the effect of gel viscoelasticity and cell restraint pressure on the leakage of electrolyte and mechanical integrity of the CNT cathode, as well as battery performance of the Li-O2 cells. In addition, as another strategy to fabricate CNT-based gel cathodes, solvent-mediated technique is exploited: CNTs, electrolytes, gelling polymers, and volatile solvents are kneaded to form paste films. After evaporation of the solvent, CNT-based gel cathodes were obtained. The relationship between composition and preparation process of the gel cathode and resultant electrochemical performance of Li-O2 cells are studied in detail. We also explore the possibility to reduce the electrolyte amount inside cathodes by gelation toward practically high energy density Li-O2 batteries.
References
[1] N. Imanishi, O. Yamamoto, Mater. Today
2014, 17, 24.
[2] L. Grande, E. Paillard, J. Hassoun, J.-B. Park, Y.-J. Lee, Y.-K. Sun, S. Passerini, B. Scrosati, Adv. Mater.
2015, 27, 784.
[3] H. Lee, D. J. Lee, M. Kim, H. Kim, Y. S. Cho, H. J. Kwon, H. C. Lee, C. R. Park, D. Im, ACS Appl. Mater. Interfaces
2020, 12, 17385.
[4] F. Li, J. Chen, Adv. Energy Mater.
2017, 7, 1602934.
[5] T. Liu, Z. Chang, Y. Yin, K. Chen, Y. Zhang, X. Zhang, Solid State Ionics
2018, 318, 88.