bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute macular neuroretinopathy in a patient with acute coronary syndrome
Authors: Agarwal Pulak , Kumar Vinod , Singh Pallavi , Banerjee Mousumi
Published: December 2020

A young man presented with bilateral diminution of vision after acute coronary syndrome. Fundus showed dark wedge-shaped perifoveal lesions in both eyes. Fundus fluorescein angiography and indocyanine angiography were normal. Optical coherence tomography showed characteristic findings of outer nuclear layer thinning and disruption of ellipsoid zone. Optical coherence tomography angiography showed flow voids in deep capillary plexus. A diagnosis of acute macular neuroretinopathy was made. The multimodal imaging findings and pathophysiology of such a scenario are presented.
Incidental finding of MEN-1 syndrome during staging and follow-up of breast carcinoma
Authors: Maria Bernardo Conde , Quadros Ana Catarina , Alves Natália , Coutinho João
Published: December 2020

Type 1 multiple endocrine neoplasia (MEN-1) syndrome is an autosomal dominant disease, associated with germline mutations in the MEN-1 tumour suppressor gene (encoding the menin protein). Recent studies, through a better characterisation of the functions of the menin protein, have started to demonstrate how changes in this protein may be related to breast cancer. We present the case of a patient whose diagnosis of MEN-1 syndrome was made during treatment for a breast tumour—this diagnosis was obtained after finding multiple neoplastic lesions that fitted the MEN-1 syndrome spectrum, during the initial staging and subsequent follow-up of a breast tumour. In line with the growing evidence that links MEN-1 syndrome to breast cancer tumorigenesis, this case report highlights the following question: should we start screening this subset of patients earlier for breast cancer?
Proton beam irradiation of uveal melanoma involving the iris, ciliary body and anterior choroid without surgical localisation (light field)
Authors: Oxenreiter Monica M , Lane Anne M , Aronow Mary Beth , Shih Helen , Trofimov Alexei V , Kim Ivana K , Gragoudas Evangelos S
Published: December 2020

Aims

To assess treatment outcomes after proton beam irradiation (PBI) without surgical localisation of uveal melanomas involving the iris, ciliary body and anterior choroid.

Methods

Retrospective chart review of 125 patients evaluated at Massachusetts Eye and Ear and treated with PBI using a light field set-up without localisation surgery between November 1975 and April 2017. The tumours were characterised as follows: iris (n=18, 14.4%), ciliary body (n=12, 9.6%), iridociliary (n=58, 46.4%), ciliochoroidal (n=24, 19.2%) and iridociliochoroidal (n=13, 10.4%). The tumours were measured by transillumination and ultrasonography before treatment. Tumours with posterior margin located less than two disc diameters from the ora serrata were treated using the light field technique. Patient outcomes after PBI were evaluated.

Results

Most patients had good vision at the time of tumour diagnosis (69.6% had baseline visual acuity (VA) of ≥20/40). Median VA at last follow-up (median follow-up: 72.1 months) was 20/63. Recurrences occurred in 12 patients (9.6%) at a median time of 4.0 years post-treatment. Recurrences were treated by repeat PBI (n=5) or enucleation (n=7). Secondary enucleation was performed in 18 patients (14.4%), and 61.1% of these were due to complications. Neovascular glaucoma (NVG) developed in 21 patients (16.8%). Of seven patients who developed NVG after anti-vascular endothelial growth factor (anti-VEGF) therapies became available, five were treated with intravitreal Avastin injections (23.8% of patients with NVG). Of 69 patients diagnosed with cataract after treatment, 51 (73.9%) were characterised as radiation-related. Death from metastatic uveal melanoma occurred in 20.8% of the cohort, with a median follow-up of 10.1 years.

Conclusions

Patients treated with PBI using a light field set-up technique experience good outcomes after irradiation. Eye preservation and retention of good VA are seen in the majority of cases, and tumour recurrence is low.
Differences in sport-related concussion for female and male athletes in comparable collegiate sports: a study from the NCAA-DoD Concussion Assessment, Research and Education (CARE) Consortium
Authors: Master Christina L , Katz Barry P , Arbogast Kristy B , McCrea Michael A , McAllister Thomas W , Pasquina Paul F , Lapradd Michelle , Zhou Wenxian , Broglio Steven P
Published: December 2020

Objectives

To examine sex differences in sport-related concussion (SRC) across comparable sports.

Methods

Prospective cohort of collegiate athletes enrolled between 2014 and 2017 in the Concussion Assessment, Research and Education Consortium study.

Results

Among 1071 concussions (females=615; 57.4%), there was no difference in recovery (median days to full return to play) (females=13.5 (IQR 9.0, 23.1) vs males=11.8 (IQR 8.1, 19.0), p=0.96). In subgroup analyses, female recovery was longer in contact (females=12.7 days (IQR 8.8, 21.4) vs males=11.0 days (IQR 7.9, 16.2), p=0.0021), while male recovery was longer in limited contact sports (males=16.9 days (IQR 9.7, 101.7) vs females=13.8 days (IQR 9.1, 22.0), p<0.0001). There was no overall difference in recovery among Division I schools (females=13.7 (IQR 9.0, 23.1) vs males=12.2 (IQR 8.2 19.7), p=0.5), but females had longer recovery at the Division II/III levels (females=13.0 (IQR 9.2, 22.7) vs males=10.6 (IQR 8.1, 13.9), p=0.0048).

Conclusion

Overall, no difference in recovery between sexes across comparable women’s and men’s sports in this collegiate cohort was found. However, females in contact and males in limited contact sports experienced longer recovery times, while females had longer recovery times at the Division II/III level. These disparate outcomes indicate that, while intrinsic biological sex differences in concussion recovery may exist, important, modifiable extrinsic factors may play a role in concussion outcomes.
Paediatric emergencies and related mortality in Nicaragua: results from a multi-site paediatric emergency registry
Authors: Bressan Silvia , Da Dalt Liviana , Chamorro Miriam , Abarca Raquel , Azzolina Danila , Gregori Dario , Sereni Fabio , Montini Giovanni , Tognoni Gianni
Published: December 2020

Background

We aim to describe the characteristics and outcomes of the severe spectrum of paediatric emergency visits using a multi-site registry developed as part of an international cooperation project.

Methods

This observational registry-based study presented descriptive statistics of clinical and outcome data on urgent-emergency paediatric visits from 7 Nicaraguan hospitals, including the national referral paediatric hospital, between January and December 2017. Extensive piloting to ensure data collection feasibility, sustainability and accuracy was carried out in 2016 with substantial input and feedback from local stakeholders.

Results

Overall, 3521 visits of patients <15 years of age, of whom two-thirds <5 years, met predefined inclusion criteria of urgent-emergency visits. Respiratory (1619/3498; 46%), gastrointestinal (407/3498; 12%) and neurological (368/3498; 11%) complaints were the most common symptoms. Malnutrition was reported in 18% (610/3448) of presentations. Mortality was 7% (233/3521); 52% (120/233) of deaths occurred in the <1-year subgroup; 32% (71/3521) of deaths occurred within the first 24 hours of presentation. The most common immediate causes of death were septic shock (99/233; 43%), respiratory failure (58/233; 25%) and raised intracranial pressure (24/233; 10%).

Conclusions

The mortality rate of urgent-emergency paediatric visits in Nicaragua is high, with younger children being most at risk and the majority of deaths being eventually caused by septic shock or respiratory failure. Our data provide useful information for the development of a Paediatric Emergency Care network to help direct training efforts, resources and logistic/organisational interventions to improve children’s health in an emergency setting in Nicaragua.
Hybrid nanomaterial treatment within a permeable tank considering irreversibility
Authors: Chu Yu-Ming , Almusawi Mohammed Baqer , Hajizadeh Mohammed Reza , Yao Shao-Wen , Bach Quang-Vu
Published: December 2020

In this paper, porous chamber with considering nanomaterial as operating fluid has been scrutinized. The transportation of nanopowder was controlled by magnetic force and insert of porous media boosts the cooling rate. Such zone needs special model to involve the impact of porous media and in this paper, non-Darcy technique was utilized. Low fraction of hybrid nanomaterial leads to good accuracy of homogeneous model and empirical correlations have been employed to forecast the features of operating fluid. Entropy generation was studied to find the influence of each term on irreversibility of unit. Also, two significant functions were calculated, namely, Be and Nu. Influences of Ra, Da and Ha on contours plots were reported in outputs. As Ra augments, the convection becomes stronger and augmentation of [Formula: see text] proves this fact. Also, temperature of elliptic surface declines about 48% with intensifying Ra. Temperature of elliptic surface augments about 34.6% with augment of Ha while it declines about 25.7% considering greater permeability. Nu augments about 238%, 11.49% with rise of Ra, Da but it declines about 28.3% with rise of Ha. Be intensifies with rise of Ha about 7.76% while it reduces about 75.2% with augmentation of Ra.
Ionic conductivity of monohydroxy alcohol liquids doped with known probe ions and analysis of the liquid structure
Authors: Lu Gui-Hua , Wang Li-Na , Zhao Xing-Yu , He Yu-Fen , Huang Yi-Neng
Published: December 2020

The specific values of the conductivity [Formula: see text] and its variation with temperature [Formula: see text] of 2-pentanol and 2-methyl-1-pentanol liquids doped with different concentrations of NaI (abbreviated as 2PEN-[Formula: see text]NaI and 2M1PEN-[Formula: see text]NaI, respectively) ([Formula: see text], 1% and 5%) are measured by the commercial equipment. The results show that whether NaI is doped or not, [Formula: see text] of 2PEN-[Formula: see text]NaI and 2M1PEN-[Formula: see text]NaI all have a conductivity peak in the range of 300–350 K different from that of typical glass-formers of small molecules. In addition, [Formula: see text] goes up with increasing [Formula: see text], and the temperature corresponding to [Formula: see text] maximum increases with rising NaI content. Moreover, there is a nonlinear behavior of [Formula: see text] with [Formula: see text], i.e., with rising [Formula: see text], [Formula: see text] decreases at low-temperatures, but increases at high-temperatures. Moreover, the liquid structure and its variation with [Formula: see text] are further analyzed based on the ionic conductivity.
Securing Applications against Side-channel Attacks through Resource Access Veto
Authors: Osman Tousif , Mannan Mohammad , Hengartner Urs , Youssef Amr
Published: December 2020

Apps on modern mobile operating systems can access various system resources with, or without, an explicit user permission. Although the OS generally maintains strict separation between apps, an app can still get access to another app’s private information, such as the user input, through numerous side-channels. For example, keystrokes and swipe gestures from a victim app can be inferred indirectly from the accelerometer or gyroscope output, allowing a zero-permission app to learn sensitive inputs such as passwords from the victim’s app. Current mobile OSes allow an app to defend itself in such situations only in some exceptional cases—e.g., by blocking screenshot captures in Android.

In this article, we propose a general mechanism for apps to defend themselves from any unwanted implicit or explicit interference from other concurrently running apps. Our AppVeto solution enables an app developer to easily configure an app’s requirements for a
safe
environment; a foreground app can request the OS to
disallow
access—i.e., to enable veto powers—to selected side-channel-prone resources to
all
other running apps for a certain (short) duration, e.g., no access to the accelerometer during password input. In a sense, we enable a finer-grained access control policy than the current runtime permission model. We implement AppVeto on Android using the Xposed framework and Procedure Linkage Table hooking techniques, without changing Android APIs. Furthermore, we show that AppVeto imposes negligible overhead, while being effective against several well-known side-channel attacks—implemented via
both
Android Java and/or Native APIs.
Progress in National Policies Supporting the Sustainable Development Goals: Policies that Matter to Income and Its Impact on Health
Authors: Raub Amy , Heymann Jody
Published: December 2020

From education to working conditions, from income to discrimination, social determinants of health (SDH) shape the majority of health outcomes. Governments are often best positioned to address the major SDH on a population-wide basis. In 2015, governments around the world committed to improving all core SDH when all countries agreed to a set of goals that would improve education, work, income, and equal opportunity, among other areas, in the Sustainable Development Goals (SDGs). Using data from the WORLD Policy Analysis Center, this article highlights how quantitative policy measures can be used to hold governments accountable for their commitments to the SDGs and thus to improve the SDH. Three areas are examined in detail to illustrate this approach to monitoring policy change: ensuring an adequate income, enhancing equal opportunities at work by prohibiting discrimination and sexual harassment, and enabling children and youth to complete their education.
Void-free Copper Electrodeposition in High Aspect Ratio, Full Wafer Thickness Through-Silicon Vias with Endpoint Detection
Authors: Schmitt Rebecca P. , Menk Lyle A. , Baca Ehren , Bower John Eric , Romero Joseph A. , Jordan Matthew B. , Jackson Nathan , Hollowell Andrew E.
Published: December 2020

High density interconnects are required for increased input/output for microelectronics applications, incentivizing the development of Cu electrochemical deposition (ECD) processes for high aspect ratio through-silicon vias (TSVs). This work outlines Cu ECD processes for 62.5 μm diameter TSVs, etched into a 625 μm thick silicon substrate, a 10:1 aspect ratio. Cu ECD in high aspect ratio features relies on a delicate balance of electrolyte composition, solution replenishment, and applied voltage. Implementing a CuSO4-H2SO4 electrolyte, which contains suppressor and a low chloride concentration, allows for a tunable relationship between applied voltage and localized deposition in the vias. A stepped potential waveform was applied to move the Cu growth front from the bottom of the via to the top. Sample characterization was performed through mechanical cross-sections and X-ray computed tomography (CT) scans. The CT scans revealed small seam voids in the Cu electrodeposit, and process parameters were tuned accordingly to produce void-free Cu features. During the voltage-controlled experiments, measured current data showed a characteristic current minimum, which was identified as an endpoint detection method for Cu deposition in these vias. We believe this is the first report of this novel endpoint detection method for TSV filling.
A Sandwich-Type Electrochemical Immunosensor based on Pd Nanocubes Functionalized MoO2 Nanospheres for Highly Sensitive Detection of CEA
Authors: Yang Qingshan , Wang Ping , Zhou Kaiwei , Tang Chunyuan , Ren Jie , Li Yueyun , Liu Qing , Dong Yunhui
Published: December 2020

In this study, a sandwich-type electrochemical immunosensor was developed for detecting carcinoembryonic antigen (CEA) effectively. The proposed electrochemical immunosensor was based on gold nanocrystals (Au NDs) as the substrate material for capturing primary antibodies and using palladium nanoscale cubics (Pd NCs) loaded on amino-functionalized MoO2 nanospheres (Pd NCs/NH2-MoO2 NSs) as a secondary antibody label. Au NDs had dendritic structures that were more conducive to capturing Ab1 and can accelerate electron transfer. MoO2 had the good catalytic capacity for reduction of H2O2 and favourable electrical conductivity. Similarly, Pd NCs had excellent catalytic performance for hydrogen peroxide reduction. Hence, the obtained Pd NCs/NH2-MoO2 NSs were more effective than Pd NCs and NH2-MoO2 NSs in catalytic reduction of hydrogen attribute to a synergistic effect, showing excellent catalysis. The proposed electrochemical immunosensor had a lower detection limit of 3.3 fg ml−1 jand a wider detection range from 10 fg ml−1 to 100 ng ml−1 (S/N = 3) for the detection of CEA under optimal experimental conditions. The proposed electrochemical immunosensor showed good sensitivity, stability, selectivity, reproducibility and its good detection performance of the immunosensor indicated that it had a broad application prospect in clinical detection.
In Situ Strain Measurement in Solid-State Li-Ion Battery Electrodes
Authors: Koohbor Behrad , Sang Lingzi , Çapraz Ömer Ö. , Gewirth Andrew A. , Sottos Nancy R.
Published: December 2020

Volumetric changes occur in electrodes of rechargeable Li-ion batteries during charge-discharge cycles. In solid-state batteries, the resulting strains cause mechanical degradation of the electrodes, solid electrolyte (SE) and/or SE-electrode interface due to the presence of brittle interfaces as well as mechanical constraints. Here, we investigate the chemo-mechanical response in working electrodes of solid-state Li-ion batteries. In situ strains are measured by full-field optical Digital Image Correlation (DIC) in a high stiffness oxide solid electrolyte, LAGP, along with a model Au working electrode during cyclic voltammetry. Mechanical deformations are correlated with electrochemical performance and damage mechanisms. The measured strains are large enough to induce cracking in the solid electrolyte. Moreover, we show the chemo-mechanical strains developed in electrodes of a solid-state battery are less reversible than those of liquid electrolyte batteries.
Review—Localized High-Concentration Electrolytes for Lithium Batteries
Authors: Cao Xia , Jia Hao , Xu Wu , Zhang Ji-Guang
Published: December 2020

The conventional LiPF6/carbonate-based electrolytes have been widely used in graphite (Gr)-based lithium (Li) ion batteries (LIBs) for more than 30 years because a stable solid electrolyte interphase (SEI) layer forms on the graphite surface and enables its long-term cycling stability. However, few of these electrolytes are stable under the more stringent conditions needed with a Li metal anode (LMA) and other anodes, such as silicon (Si), which exhibit large volume changes during charge/discharge processes. Many different approaches have been developed lately to stabilize Li metal batteries (LMBs) and Si-based LIBs. From this aspect, localized high-concentration electrolytes (LHCEs) have unique advantages: not only are they stable in a wide electrochemical window, they can also form stable SEI layers on LMA and Si anode surfaces to enable their long-term cycling stability. The ultrathin SEI layer formed on a Gr anode can also improve the safety and high-rate operation of conventional LIBs. In this paper, we give a brief summary of our recent work on LHCEs, including their design principle and applications in both LMBs and LIBs. A perspective on the future development of LHCEs is also discussed.
(Invited) Growth of Self-Ordered Porous Anodic Oxide Nanomaterials By Coupled Ion Migration and Viscous Flow
Authors: Mishra Pratyush , Hebert Kurt
Published: December 2020

Porous anodic oxide (PAO) films are self-organized porous oxide nanomaterials formed by electrochemical oxidation. PAO includes porous anodic alumina and TiO2 nanotube layers. These films eventually evolve into a hexagonally-ordered array of parallel cylindrical pores or nanotubes of order 100 nm diameter, with a characteristic interpore spacing that scales directly with the cell voltage.

We explore the roles of mechanical stress and oxide flow in self-ordering, through a modeling analysis of stress-driven viscous flow of oxide (1). The model is based on coupled viscous flow of oxide and stress- and electric field-driven migration of metal and oxygen ions (2). Stress at the film interfaces is generated by ion-transfer processes and relaxed by viscous flow, resulting in layers with elevated compressive or tensile stress within a few nm of the interfaces (3,4). Experimental evidence for these layers has been found from in situ stress measurements (5,6). We present linear stability analysis incorporating the surface stress boundary conditions in the coupled oxide flow-electrical migration model of Houser and Hebert (2).

For porous alumina, the calculations reveal self-organized pattern formation with steady-state pore spacing-voltage scaling ratios that compare favorably to those found experimentally (1). The scaling ratios are independent of oxide viscosity or uncertainties in the values of any other model parameters. The stress driving oxide flow arises at the oxide-solution interface due to strong electrolyte anion adsorption, which blocks direct oxide deposition on the surface itself. New results for TiO2 nanotube layers are presented. Near-surface stress is not present in TiO2 nanotube layers (6); instead, compressive stress driving flow arises at the metal-oxide interface from the volume change upon conversion of metal to oxide.

REFERENCES

P. Mishra and K. R. Hebert, Electrochim. Acta, 340, 135879 (2020).

J. E. Houser and K. R. Hebert, Nature Mater., 8, 415 (2009).

K. R. Hebert, P. Mishra, J. Electrochem. Soc., 165, E737 (2018).

K. R. Hebert, P. Mishra, J. Electrochem. Soc., 165, E744 (2018).

Ö. Ö. Çapraz, P. Shrotriya, P. Skeldon, G. E. Thompson, K. R. Hebert, Electrochim. Acta, 167, 404 (2015).

Q. Dou, P. Shrotriya, W. F. Li, K. R. Hebert, Electrochim. Acta, 292, 676 (2018).

Q. Dou, P. Shrotriya, W. F. Li, K. R. Hebert, Electrochim. Acta, 295, 418 (2019).
Electrochemical Behavior of Salt Film and Its Role in Pit Growth
Authors: Li Tianshu , Scully John R. , Frankel Gerald S.
Published: December 2020

In a recently published series of papers for pitting corrosion,1-5 a new concept of maximum pit dissolution current density, i
diss,max, was proposed to establish a unifying framework for pit growth stability. This framework provides an opportunity to revisit several key topics of this field and generates new insights to interpret the previous observations in a self-consistent way. In this work, the unifying framework is further expanded to establish a mathematical model describing the electrochemical behavior of salt film after it precipitates, i.e. the situation when i
diss,max > i
lim. It can be mathematically shown that the main function of a salt film during diffusion-controlled pit growth is to accommodate the extra potential of (E
max - E
sat) by regulating its thickness to adjust the actual potential at the pit surface to E
sat, thus restricting the anodic dissolution current density at the diffusion-limited value.4 The salt film will respond to any changes of the applied potential, temperature, pit depth, and perforation radius of the pit cover. In addition, an analytical model is proposed for salt film growth based on ion transport, in which the film grows at the metal/film interface and dissolves at film/solution interface. Any disturbance causing a difference in growth and dissolution rates will trigger a self-regulating process that will, in turn, bring the pitting system back to steady state.

Acknowledgments: This work was supported as part of the Center for Performance and Design of Nuclear Waste Forms and Containers, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0016584.

Reference

G. S. Frankel, T. Li, and J. R. Scully, Journal of the Electrochemical Society,
164 (4), C180-C181 (2017).

T. Li, J. R. Scully, and G. S. Frankel, Journal of The Electrochemical Society,
165 (9), C484-C491 (2018).

T. Li, J. R. Scully, and G. S. Frankel, Journal of The Electrochemical Society,
165 (11), C762-C770 (2018).

T. Li, J. R. Scully, and G. S. Frankel, Journal of The Electrochemical Society,
166 (6), C115-C124 (2019).

T. Li, J. R. Scully, and G. S. Frankel, Journal of The Electrochemical Society,
166 (11), C3341-C3354 (2019).
(Invited) Metal Oxide Decorated Porous Silicon Interfaces for Sensor Applications: The Question of Water Interaction, Stability, Platform Diversity, Sensitivity, and Selectivity
Authors: Gole James L.
Published: December 2020

Key parameters of a metal oxide nanostructure modified porous silicon (PSi) template that can affect the development and performance of PSi-based sensors are considered1. The importance of pore selection and direct in-situ nitrogen functionalization are discussed. Metal oxide (MOx , MxO, x≥1) nanostructured island sites, deposited to select, well defined and reproducible micron sized p and n-type silicon pores (0.7–1.5 µ diameter) provide sensitivity and selectivity as they facilitate rapid “Fickian” analyte diffusion to these highly active sites. The metal oxide nanoparticles are trapped by a thin nanopored wall covering preventing their sintering at elevated temperatures. Variable sensitivities of the metal oxide nanostructured sites are well predicted within the recently developed Inverse Hard/Soft-Acid/Base (IHSAB) model. Ready nitrogen functionalization can further provide the conversion of the decorating metal oxides and an oxidized PSi interface from hydrophilic to hydrophobic character. The decrease in water interaction provides enhanced stability. Selectivity in the measurement of multiple gases is possible with a combination of nanostructure based detection matrices, p and n-type charge carrier variation, time dependent diffusion response, and pore structure influenced sensitivity as the range of variable responses is dominated by the molecular electronic structure of the nanostructured island sites as evaluated using the IHSAB concept. Fast Fourier Transfer techniques (pulsed mode operation) can facilitate low analyte consumption and higher analyte selectivity, and provide the ability to assess false positive signals. A new Fermi distribution–based adsorption isotherm is superior to other isotherms in modeling the PSi system.

AIMS Electronics and Electrical Engineering, 4(1): 87-113,2020 DOI: 10.3934/ElectrEng.2020.1.87
(Keynote) Actual Pore Morphology of Anodic Alumina Films: Straight or Branching?
Authors: Ono Sachiko
Published: December 2020

Anodic oxide film on aluminum has attracted attention as a starting structure for nanomaterials because of its nano-sized straight tube shape. In this case, a straight pore of the films formed in oxalic acid electrolyte or sulfuric acid electrolyte is generally used. On the other hand, a film with a branched pore structure, like a chromic acid film, is used for practical aluminum materials such as aircraft alloy containing silicon and copper. This is because the branching action of the pores has the effect of suppressing the inhibition of uniform film growth due to the non-uniform base composition of the alloy material. Although the branched structure of the chromic acid film is considered to be unique as anodic film, it has been revealed that when the solubility of the electrolyte is low, the pore branching often appears accompanied by minute dielectric breakdown [1, 2].

Recently, however, the authors found that by performing detailed TEM observation of the pore wall of anodic films, considerable branching of the pores occurred even when electrolysis was performed at 40 V in oxalic acid electrolyte, which is the self-ordering condition. The branching of the pores stops at the early stage of the process and remains as traces in the pore walls as radial fine pores. When the subsequent anodic oxidation continues, these radial micropores disappear due to chemical dissolution reaction of the oxide to the electrolyte. In this study, the actual morphology and controlling factors of pore branching in not only chromic acid electrolyte, but also of pore branching found in films formed by other typical anodizing electrolytes such as sulfuric acid, oxalic acid and phosphoric acid will be reported.

[1] S. Ono, S. Chiaki, T. Sato, J. Surf. Finish. Soc. Jpn, 26, 456 (1975) DOI:10.4139/sfj1950.26.456

[2] S. Ono, T. Kawaguchi, H. Ichinose, Y. Ishida, N. Masuko, J. Surf. Finish. Soc. Jpn, 40, 1361 (1989) DOI:10.4139/sfj.40.1361
Binary Aluminium-Lanthanoid Material Libraries Studied in a Combinatorial Approach
Authors: Hassel Achim Walter
Published: December 2020

Aluminium and the f-elements following the element lanthanum, the so called lanthanoids have in common to be trivalent in their oxides. Exceptions are found for near f0, f7 and f14 electron configurations. Due to the large mismatch between the atomic radii of aluminium and the lanthanoids the latter ones cause a significant lattice distortion in their binary alloys. The unprecendented chance of basic understanding comes from the fact that the stepwise addition of f electrons in an inner shell cause a charge shielding of the nucleus, resulting in a valence electron shell contraction. In this study combinatorial alloys of aluminium and various lanthanoids where prepared by cosputtering in material libraries. A subsequent SEDX characterisation yields a full compositional map and also other physical data such as electron microscopic imaging and XRD mapping provided information about each single composition. The scanning droplet cell microscope was then employed to perform a comprehensive electrochemical characterisation including OCP, EIS and CV on each single alloy. Due to the large atomic ratio mismatch significant amorphisation was found in a lot of cases. Those flat glassy alloys provide surprisingly low corrosion rates indicating crystallinity itself as well as high energy grain boundaries are prone to a simplified corrosion attack.

In an attempt to complement the experimental approaches a fundamental theoretical attempt is introduced that allows computing Pourbaix diagrams of these alloys in various electrolytes. Finally the two methods are summarized in a principal high throughput method for a drastically accelerated material evaluation approach.
Asymptotic Reduction Methods for the Parameter Estimation and Simulation of Lithium-Ion Batteries
Authors: Brosa Planella Ferran , Widanage Widanalage Dhammika
Published: December 2020

Physics-based battery models are a very powerful tool to study batteries as they provide insight on the internal states, such as the concentrations or potentials. However, these models are very complex and running them is computationally expensive, which makes them not suitable for many applications such as parameter estimation and battery control. Therefore, we need to reduce these models to others of lower complexity but that still retain most of the prediction capabilities.

Asymptotic methods provide tools to reduce the models in a systematic way, keeping track of the validity and accuracy of the reduced model. These asymptotically reduced models present the advantage over ad hoc reductions that the reduced model is consistent with the full model and that we can check if the reduced model is valid in a given parameter set before even solving the model. This is especially useful in complex models with a lot of parameters, such as the Doyle-Fuller-Newman (DFN) model.

Here we present an asymptotic model reduction for the particular applications of parameterisation and battery control. This reduction allows us to derive specific simple models with the complexity of the Single Particle Model (SPM) which, for a given application or operating conditions, capture the most relevant features of the full model. We first derive a reduced coupled thermal-electrochemical model and we parameterise it for a commercial cylindrical cell (LG M50). The complexity of this model makes it suitable for control applications. Then, we show how we can use asymptotically reduced models to determine some of the parameters of the model from experimental measurements of Galvanostatic Intermittent Titration Technique (GITT). This method ensures that the parameters obtained are consistent with the DFN model, and highlights the limitations and possible extensions of the technique.
(Invited) The Pillaring Effect on Layered Transition Metal Oxide Battery Cathode
Authors: Fan Qinglu , Niu Fangzhou , Liu Hao
Published: December 2020

Layered transition metal oxides are widely used as cathode materials for lithium- and sodium-ion batteries. Their high theoretical capacity is predicated on the complete extraction of the intercalant cations between the transition metal oxide layers. However, deep charge exceeding 70% of the theoretical capacity induces collapse of the interlayer, which leads to the intergranular cracking of the secondary particles commonly used in the electrode. Such irreversible microstructural change is a primary cause of the capacity degradation that limits the practical realization of the material’s full theoretical capacity. One approach to mitigate the layer collapse is through the introduction of pillar ions in the interlayer. This work investigates the pillaring effect on the function of the layered transition metal oxides as battery cathodes.
Oxygen Redox Reactions in LiCoO2 Cathode without O-O Bonding during Charge-Discharge
Authors: Hu Enyuan , Li Qinghao , WANG Xuelong , Yu Xiqian , Yang Wanli , Yang Xiao-Qing
Published: December 2020

LiCoO2 (LCO) is a widely used cathode material for lithium-ion batteries with superior volumetric energy density and tap density. Traditionally, only about 50% of the total lithium content are utilized in practical applications since it is believed that more than 50% Li extraction can cause irreversible reactions and structural degradation with oxygen releases from the lattice. However, there has always been a great interest in going beyond the delithiation level of x=0.5 in Li1-xCoO2 to utilize the full potential of its energy density. Therefore, a clarification of the controversial issues related with the oxygen activities in highly delithiated LCO becomes critical for guiding the development of high energy density LCOs . In this work, we combined the results of several modern experimental techniques, especially resonant inelastic X-ray scattering (RIXS) and neutron scattering pair distribution function analysis (nPDF), together with the theoretical calculations to study the nature of the oxygen activities at highly delithiated state of LCO. Our results conclude that the lattice-oxygen-redox nature of LCO, which means the oxygen redox takes place globally in lattice, are quite different from the oxygen oxidation through dimerization reported in literature. Our RIXS results directly reveal the reversible lattice oxygen redox, and nPDF results show that the O-O pair distance is shortened from 2.63 Å for pristine state to 2.47 Å for highly delithiated state of LCO. Pairs with similar short length were previously associated with O-O bond formation in 4d/5d systems. Strikingly, although with the shortened O-O distance, our theoretical calculations show that no O-O bonding is formed in LCO, in sharp contrast with the calculation results of 4d/5d transition-metal oxides (Ru and Ir), as well as 3d Li-rich layered systems, based on exactly the same theoretical calculation method. These new results challenge the widely accepted O-O bond formation being the natural result of oxygen redox in highly delithiated LCO system. Our combined structural, spectroscopic and theoretical results clearly reveal that, while the lattice-oxygen-oxidation takes place in LCO, the broadly accepted O-O bonding is not a necessary condition. In addition, our findings indicate that oxygen release is not necessarily the intrinsic channel of oxidized oxygen in LCO at highly charged states, providing the rationality for achieving a reversible deep delithiation and high energy density in LCO based electrodes.

Acknowledgements

The work done at Brookhaven National Laboratory was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the U.S. Department of Energy through the Advanced Battery Materials Research (BMR) Program under contract DE-SC0012704.
Enhanced High-Temperature Stability of Li-Ion Battery with Li-Rich Oxide Cathode By Localized High-Concentration Electrolyte
Authors: Zhang Xianhui , Jia Hao , Xu Yaobin , Zou Lianfeng , Engelhard Mark H , Matthews Bethany E. , Wang Chongmin , Zhang Jason , Xu Wu
Published: December 2020

Lithium (Li)-rich manganese (Mn)-rich oxides (LMR) have been considered as feasible cathode materials for high-energy lithium ion batteries because they possess high theoretical specific energy over 900 Wh kg−1. However, the undesirable cathode/electrolyte interfacial reaction due to the high working voltages, which results in electrolyte decomposition, transition-metal ion dissolution and surface corrosion, is considered one of the obstacles that significantly prevent their applications in electric vehicles for years.[1, 2] Although numerous efforts have been devoted to address the surface stability issues on LMR, most of them were limited to room temperature. The continuous upsurge in demand for electric vehicles requires lithium ion batteries to be operated under elevated temperatures. While, the state-of-the-art LiPF6-organocarbonate electrolytes are not compatible with LMR cathode due to the high operating voltage, which also get worse at elevated temperatures.[3] Here, an optimized localized high-concentration electrolyte (LHCEs) is studied in graphite (Gr)-based LMR full cells at 25, 45 and 60 °C. The cycling stabilities and the interfacial properties on the surfaces of both cathode and anode under different temperatures are systemically investigated. It is revealed that the LHCE enables the formation of more protective electrode/electrolyte interphases on both anode and cathode, which, in turn, lead to significantly improved cycling stability and enhanced rate capability under the selected temperatures. The electrode/electrolyte interphases formed in LHCE are found to be less susceptible towards elevated temperatures than those in conventional LiPF6-based electrolyte. The mechanistic understanding on the function of the LHCE in Gr||LMR cells under high temperatures provides valuable perspectives of electrolyte development for practical application of LMR cathodes in high energy density batteries over a wide temperature range.

References

C. Wang, et al., Overlooked electrolyte destabilization by manganese (II) in lithium-ion batteries. Nature Communications, 2019, 10(1), 3423.

H. Pan, et al., Li- and Mn-rich layered oxide cathode materials for lithium-ion batteries: a review from fundamentals to research progress and applications, Molecular Systems Design & Engineering, 2018, 3(5), 748.

M.-T.F., Rodrigues, et al., A materials perspective on Li-ion batteries at extreme temperatures, Nature Energy, 2017, 2(8), 17108.
Pre-Lithiation of Anode for Lithium Ion Batteries
Authors: Lu Wenquan , Qin Yan , Trask Stephen E. , Dunlop Alison R , Jansen Andrew N.
Published: December 2020

Silicon monoxide (SiO), as an anode for lithium ion batteries (LIB), offers a specific capacity of 1750 mAh/g and a volumetric capacity of 1547 Wh/L,[1] which is less than Si, but still a significant improvement from the current commercial graphite anode, which has a specific capacity of 350 mAh/g and a volumetric capacity of 719 Wh/L. Compared to Si, SiO offers much more stable cycling, and is therefore the more practical material for near-future applications. The drawback of SiO is the large capacity loss observed in the initial cycles. The 1st cycle coulombic efficiency of silicon monoxide is usually lower than 70% due to the parasitic reactions between lithium and the oxide.

To address the problem, prelithiation reagents can be added to either anode or cathode electrodes to compensate for the lithium loss caused by the irreversible reactions. However, dead weight left by the pre-lithiation agent adversely affects the energy density of LIB. Electrochemical pre-lithiation will only put the lithium ions into the anode and leaves no other compound behind, which is considered an ideal prelithiation method. In addition, the electrochemical pre-lithiation on the anode has the potential to be compatible with the existing roll-to-roll manufacturing line and could be immediately applicable to the current state-of-the-art LIB anodes.

In this work, we conducted the electrochemical pre-lithiation of large size graphite and SiO anode electrodes in pouch cells to prove the concept. After pre-lithiation, no damage and handling issues were encountered during subsequent cleaning, drying, cell fabrication, and testing. Good electrochemical performance of the pre-lithiated graphite and SiO electrodes were obtained in both half cells and full cells. According to calculation, the pre-lithiation speed is challenging and needs to be addressed to match roll-to-roll electrode coating speed. Additionally, electrochemical pre-lithiation on graphite powder was attempted and results will be discussed.

Acknowledgements:

We gratefully acknowledge the support from Peter Faguy at the U.S. Department of Energy’s (DOE) office of Energy Efficiency & Renewable Energy (EERE) Vehicle Technologies Office. This work is conducted under the Cell Analysis, Modeling, and Prototyping (CAMP) Facility at Argonne National Laboratory. Argonne National Laboratory is a U.S. Department of Energy Office of Science Laboratory operated under Contract No. DE-AC02-06CH11357.

[1] Obrovac, M. N.; Chevrier, V. L., Alloy Negative Electrodes for Li-Ion Batteries. Chemical Reviews 2014, 114 (23), 11444-11502.
(Invited) In Operando and in Situ techniques for Intercalation Compounds in Li-Ion and All-Solid-State Batteries
Authors: Zaghib Karim , Zhu Wen , Kaboli Shirin , Demers Hendrix , Trudeau Michel , Paolella Andrea , Guerfi Abdelbast , Julien Christian M , Mauger Alain , Armand Michel , Goodenough John Bannister
Published: December 2020

We will present the results and supporting video files of several in operando techniques used to study lithium-ion and solid-state batteries, such as in situ scanning electron microscopy (SEM), in situ transmission electron microscopy (TEM), in
situ Raman spectroscopy, in situ X-ray diffraction and in situ UV visible. These studies help understand several mechanisms, including volume expansion of anodes such as Si (300%), lithium metal (20%), graphite (10%) and LTO (0%). They are also used to measure the thickness of the anode, cathode and electrolyte through the charge/discharge cycle. The mechanism of lithium dendrite was also studied and its details will be presented.

Blend-based solid polymer electrolyte (SPE) lithium-sulfur cells were studied in operando using two techniques: SEM and ultraviolet-visible absorption spectroscopy (UV-vis). During the operation of these cells, extensive polysulfide dissolution in the solid polymer electrolyte (cross-linked polyethylene oxide) leads to the formation of a catholyte. A clear micrograph of the thick passivation layer on the sulfur-rich anode and the decreased SPE thickness due to cycling confirmed the failure mechanism: capacity decays by reducing the amount of active material and by contributing to a charge-inhibiting mechanism called polysulfide shuttle. The formation of elemental sulfur is clearly visible in real time during the charge process beyond 2.3 V. The non-destructive in operando UV-vis study also showed the presence of characteristic absorption peaks evolving with cycling, demonstrating the accumulation of various polysulfide species, and the predominant formation of S4
2- and of S6
2- during discharge and charge, respectively. This finding implies that the charge and discharge reactions are not completely reversible and proceed along different pathways.
(Invited) Superstructure Controls First Cycle Voltage Hysteresis in O-Redox Cathode Materials
Authors: Bruce Peter G.
Published: December 2020

The cathode is a major constraint on the energy density of Li-ion batteries. State-of-the-art materials, such as Li(Mn0.8Ni0.1Co0.1)O2, are limited in their ability to store charge by the amount of available transition metal redox. It is now known these limits can be surpassed by storing charge on the oxide ions (oxygen redox) in so-called lithium-rich transition metal (TM) oxides, e.g. Li[Li0.2Ni0.2Mn0.6]O2. However, such O-redox cathodes suffer from several problems one of which is that, in almost all known cases, the high voltage plateau associated with oxide oxidation is followed by reduction at a much lower voltage (1st cycle hysteresis) leading to a substantial drop in energy density. Here, we discuss the origin of 1st cycle voltage hysteresis and show that it can be controlled by the superstructure ordering within the TM layer.

We compare two layered Na-ion O-redox compounds as model systems with very similar compositions and structure but divergent 1st cycle voltage profiles. In P2-type Na0.75[Li0.25Mn0.75]O2 with honeycomb ordering of Li and Mn in the TM layer, present in almost all O-redox compounds, substantial voltage hysteresis is observed. Whereas, for P2-type Na0.6[Li0.2Mn0.8]O2 with unique ribbon ordering, reversible high voltage O-redox is realised. The origin of voltage hysteresis is shown to be rooted in the formation of molecular O2 on charge that is trapped in in the bulk of honeycomb ordered cathodes and which can be reduced on discharge. O2 formation can be suppressed with ribbon ordering in the TM layer. The implications for future O-redox materials will also be considered.

Figure 1
(Invited) Multiscale Modelling of Titanium Oxide Growth and Dissolution in Fluoride-Containing Electrolytes
Authors: Bojinov Martin S. , Betova Iva G. , Karastoyanov Vasil I. , Stancheva Mina J.
Published: December 2020

Nanostructured valve metal oxides have been extensively investigated due to the variety of applications related to their valuable chemical and physical properties, including mechanical and thermal resistance, catalytic and photocatalytic activity, and biocompatibility. The technology to form well defined porous anodic oxides on titanium will strongly benefit from an optimization of the process parameters based on deterministic modelling. The relatively large number of adjustable parameters often precludes the unambiguous interpretation of steady-state and transient electrochemical data in terms of a unique kinetic model.

An approach to overcome this ambiguity by parameterization of the models of barrier film growth [1, 2] on Ti and its alloys (Figure 1) using a combination of in-situ EIS in a large frequency range, dynamic high-frequency impedance and photocurrent measurements, combined with ex-situ characterization of the oxides by X-ray photoelectron spectroscopy (XPS) is presented. Additional estimates of kinetic parameters are derived from density functional theory (DFT) modelling of adsorption of water and fluoride on Ti and TiO2 [3, 4]. Ways to extract information on the rate-limiting steps of the process of passive film formation, growth and restructuring are described and the significance of the obtained parameters for the kinetics of barrier film growth and dissolution is outlined.

Stancheva, M. Bojinov, Electrochim. Acta 78, 65 (2012).

Bojinov, I. Betova, V. Karastoyanov, Electrochim. Acta 344, 136137 (2020).

Stancheva, B. Diawara, F. Lebreau, M. Bojinov, J. Electrochem. Soc. 161, E3188 (2014).

Betova, M. Bojinov, V. Karastoyanov, M. Stancheva, Computational Mater. Sci.171, 109260 (2020).

Acknowledgments: The financial support of the National Science Fund of Bulgaria under contract ДН19/3-2017 „Modeling, optimization and modification of nanoporous anodic oxide films as catalysts for water photoelectrolysis“is gratefully acknowledged.

Figure 1