scholarly journals Optimizing Discharge Capacity of Graphite Nanosheet Electrodes for Lithium–Oxygen Batteries

Batteries ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 36
Author(s):  
Philipp Wunderlich ◽  
Jannis Küpper ◽  
Ulrich Simon
Keyword(s):  
Discharge Capacity ◽  
Synergistic Effects ◽  
Porous Electrode ◽  
Specific Capacity ◽  
Discharge Process ◽  
Discharge Current Density ◽  
Air Electrode ◽  
High Discharge Capacity ◽  
Test Parameters ◽  
The Impact

Lithium–oxygen (Li-O2) batteries require scalable air electrode concepts and a sensible choice of operation parameters to achieve their promised energy densities. Furthermore, different test parameters are often investigated individually, but rarely brought together in order to optimize the discharge process and unlock the full discharge capability of an air electrode. In this work, we present a highly porous electrode based on graphite nanosheets (GNS) and discuss the impact of the discharge current density and the oxygen pressure as battery test parameters, as well as the electrolyte salt and volume, on the discharge behavior. In particular, changing the electrolyte salt from LiNO3 to LiTFSI proved to be an important step towards better cell performance, because synergistic effects of the electrolyte and GNS greatly enhance the carbon-specific capacity. The optimized combination of the aforementioned parameters enabled a remarkably high discharge capacity of 56.3 mAh/cm2 (5860 mAh/gcarbon) obtained at 150 µA/cm2 (15.6 mA/gcarbon), resulting in the almost complete conversion of the lithium anode. These experimental results are an important step towards practical high-capacity air electrodes for Li-O2 batteries.

scholarly journals Post-Synthetic and In Situ Vacancy Repairing of Iron Hexacyanoferrate Toward Highly Stable Cathodes for Sodium-Ion Batteries

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Min Wan ◽  
Rui Zeng ◽  
Jingtao Meng ◽  
Zexiao Cheng ◽  
Weilun Chen ◽  
...  
Keyword(s):  
Discharge Capacity ◽  
Specific Capacity ◽  
Sodium Ion ◽  
Side Reactions ◽  
Sodium Ion Batteries ◽  
Solution Synthesis ◽  
High Quality ◽  
Vacancy Defects ◽  
High Discharge Capacity

AbstractIron hexacyanoferrate (FeHCF) is a promising cathode material for sodium-ion batteries. However, FeHCF always suffers from a poor cycling stability, which is closely related to the abundant vacancy defects in its framework. Herein, post-synthetic and in-situ vacancy repairing strategies are proposed for the synthesis of high-quality FeHCF in a highly concentrated Na4Fe(CN)6 solution. Both the post-synthetic and in-situ vacancy repaired FeHCF products (FeHCF-P and FeHCF-I) show the significant decrease in the number of vacancy defects and the reinforced structure, which can suppress the side reactions and activate the capacity from low-spin Fe in FeHCF. In particular, FeHCF-P delivers a reversible discharge capacity of 131 mAh g−1 at 1 C and remains 109 mAh g−1 after 500 cycles, with a capacity retention of 83%. FeHCF-I can deliver a high discharge capacity of 158.5 mAh g−1 at 1 C. Even at 10 C, the FeHCF-I electrode still maintains a discharge specific capacity of 103 mAh g−1 and retains 75% after 800 cycles. This work provides a new vacancy repairing strategy for the solution synthesis of high-quality FeHCF.

TiO2 Nanosheet-Redox Graphene Oxide/Sulphur Cathode for High-Performance Lithium-Sulphur Batteries

2020 ◽  
Vol 20 (3) ◽  
pp. 1715-1722
Author(s):  
Shu Hong ◽  
Yunzhao Han ◽  
Kun Zhang ◽  
Mingbo Wang ◽  
Nana Cui ◽  
...  
Keyword(s):  
Discharge Capacity ◽  
Active Sites ◽  
High Performance ◽  
Synergistic Effects ◽  
Low Cost ◽  
High Energy ◽  
High Energy Density ◽  
High Discharge ◽  
High Discharge Capacity ◽  
Specific Discharge

Lithium-sulphur batteries are considered as some of the most potent secondary-battery systems. These batteries are expected to have extensive applications in fields requiring high-energy density. However, such applications are hindered by some serious intrinsic obstacles. Herein, TiO2 nanosheets-rGO/sulphur (TiO2 NS-rGO/S) composites were fabricated through a two-process hydrothermal method. TiO2 nanosheets served as active sites for polysulphide absorption, whereas rGO offered space for sulphur improvement and TiO2 NS-rGO/S composites. The TiO2 NS-rGO/S composite exhibited high discharge capacity of 1099 mAh·g-1 at 0.2 C rate and retained a capacity of 690 mAh·g-1 after 100 cycles, with high sulphur loading of 3 mg·cm-2. The high initial specific discharge capacity and improved cyclic stability were attributed to the synergistic effects of TiO2 nanosheets and rGO. These results indicated that the simple, low-cost and scalable method provides a novel perspective on practical utilisation of lithium-sulphur batteries.

Diabetes Discharge Planning and Transitions of Care: A Focused Review

2019 ◽  
Vol 15 (2) ◽  
pp. 111-117 ◽  
Author(s):  
Robin L. Black ◽  
Courtney Duval
Keyword(s):  
Patient Outcomes ◽  
Hospital Admissions ◽  
Discharge Planning ◽  
Medication Management ◽  
Hospital Readmissions ◽  
The United States ◽  
Transitions Of Care ◽  
Discharge Process ◽  
The Impact ◽  
Diabetes Patients

Background: Diabetes is a growing problem in the United States. Increasing hospital admissions for diabetes patients demonstrate the need for evidence-based care of diabetes patients by inpatient providers, as well as the importance of continuity of care when transitioning patients from inpatient to outpatient providers. Methods: A focused literature review of discharge planning and transitions of care in diabetes, conducted in PubMed is presented. Studies were selected for inclusion based on content focusing on transitions of care in diabetes, risk factors for readmission, the impact of inpatient diabetes education on patient outcomes, and optimal medication management of diabetes during care transitions. American Diabetes Association (ADA) guidelines for care of patients during the discharge process are presented, as well as considerations for designing treatment regimens for a hospitalized patient transitioning to various care settings. Results: Multiple factors may make transitions of care difficult, including poor communication, poor patient education, inappropriate follow-up, and clinically complex patients. ADA recommendations provide guidance, but an individualized approach for medication management is needed. Use of scoring systems may help identify patients at higher risk for readmission. Good communication with patients and outpatient providers is needed to prevent patient harm. A team-based approach is needed, utilizing the skills of inpatient and outpatient providers, diabetes educators, nurses, and pharmacists. Conclusion: Structured discharge planning per guideline recommendations can help improve transitions in care for patients with diabetes. A team based, patient-centered approach can help improve patient outcomes by reducing medication errors, delay of care, and hospital readmissions.

scholarly journals Controlled Nanostructuration of Cobalt Oxyhydroxide Electrode Material for Hybrid Supercapacitors

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2325
Author(s):  
Ronan Invernizzi ◽  
Liliane Guerlou-Demourgues ◽  
François Weill ◽  
Alexia Lemoine ◽  
Marie-Anne Dourges ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Energy Storage ◽  
Specific Surface ◽  
Electrode Materials ◽  
Specific Capacity ◽  
Hybrid Supercapacitors ◽  
Cobalt Oxyhydroxide ◽  
Precipitation Medium ◽  
The Impact

Nanostructuration is one of the most promising strategies to develop performant electrode materials for energy storage devices, such as hybrid supercapacitors. In this work, we studied the influence of precipitation medium and the use of a series of 1-alkyl-3-methylimidazolium bromide ionic liquids for the nanostructuration of β(III) cobalt oxyhydroxides. Then, the effect of the nanostructuration and the impact of the different ionic liquids used during synthesis were investigated in terms of energy storage performances. First, we demonstrated that forward precipitation, in a cobalt-rich medium, leads to smaller particles with higher specific surface areas (SSA) and an enhanced mesoporosity. Introduction of ionic liquids (ILs) in the precipitation medium further strongly increased the specific surface area and the mesoporosity to achieve well-nanostructured materials with a very high SSA of 265 m2/g and porosity of 0.43 cm3/g. Additionally, we showed that ILs used as surfactant and template also functionalize the nanomaterial surface, leading to a beneficial synergy between the highly ionic conductive IL and the cobalt oxyhydroxide, which lowers the resistance charge transfer and improves the specific capacity. The nature of the ionic liquid had an important influence on the final electrochemical properties and the best performances were reached with the ionic liquid containing the longest alkyl chain.

scholarly journals A New Approach for Design Optimization and Parametric Analysis of Symmetric Compound Parabolic Concentrator for Photovoltaic Applications

2021 ◽  
Vol 13 (9) ◽  
pp. 4606
Author(s):  
Faisal Masood ◽  
Perumal Nallagownden ◽  
Irraivan Elamvazuthi ◽  
Javed Akhter ◽  
Mohammad Azad Alam
Keyword(s):  
Parametric Analysis ◽  
Concentration Ratio ◽  
Synergistic Effects ◽  
Geometric Optimization ◽  
Design Parameters ◽  
Imaging Device ◽  
Compound Parabolic Concentrator ◽  
Photovoltaic Applications ◽  
Half Angle ◽  
The Impact

A compound parabolic concentrator (CPC) is a non-imaging device generally used in PV, thermal, or PV/thermal hybrid systems for the concentration of solar radiation on the target surface. This paper presents the geometric design, statistical modeling, parametric analysis, and geometric optimization of a two-dimensional low concentration symmetric compound parabolic concentrator for potential use in building-integrated and rooftop photovoltaic applications. The CPC was initially designed for a concentration ratio of “2×” and an acceptance half-angle of 30°. A MATLAB code was developed in house to provoke the CPC reflector’s profile. The height, aperture width, and concentration ratios were computed for different acceptance half-angles and receiver widths. The interdependence of optical concentration ratio and acceptance half-angle was demonstrated for a wide span of acceptance half-angles. The impact of the truncation ratio on the geometric parameters was investigated to identify the optimum truncation position. The profile of truncated CPC for different truncation positions was compared with full CPC. A detailed statistical analysis was performed to analyze the synergistic effects of independent design parameters on the responses using the response surface modeling approach. A set of optimized design parameters was obtained by establishing specified optimization criteria. A 50% truncated CPC with an acceptance half-angle of 21.58° and receiver width of 193.98 mm resulted in optimum geometric dimensions.

scholarly journals dual-ion charge-discharge behaviors of Na-NiNc and NiNc-NiNc batteries

2021 ◽  
Author(s):  
Jinkwang Hwang ◽  
Rika Hagiwara ◽  
Hiroshi Shinokubo ◽  
Ji-Young Shin
Keyword(s):  
Discharge Capacity ◽  
Electrode Material ◽  
High Stability ◽  
Coulombic Efficiency ◽  
Active Electrode ◽  
High Discharge ◽  
High Discharge Capacity ◽  
Charge Discharge ◽  
High Coulombic Efficiency

Dual-ion sodium-organic secondary batteries were provided with antiaromatic porphyrinoid, NiNc as an active electrode material, which implemented inherent charge-discharge behaviors with high discharge capacity, high stability, high Coulombic efficiency with...

Debris/Micrometeoroid Impacts and Synergistic Effects on Spacecraft Materials

MRS Bulletin ◽  
2010 ◽  
Vol 35 (1) ◽  
pp. 41-47 ◽  
Author(s):  
E. Grossman ◽  
I. Gouzman ◽  
R. Verker
Keyword(s):  
Space Debris ◽  
Synergistic Effects ◽  
Degradation Mechanism ◽  
Space Environment ◽  
Materials Properties ◽  
Gas Gun ◽  
Naturally Occurring ◽  
Space Activity ◽  
The Impact ◽  
Debris Impact

AbstractIn the last 40 years, the increased space activity created a new form of space environment of hypervelocity objects—space debris—that have no functional use. The space debris, together with naturally occurring ultrahigh velocity meteoroids, presents a significant hazard to spacecraft. Collision with space debris or meteoroids might result in disfunction of external units such as solar cells, affecting materials properties, contaminating optical devices, or destroying satellites. The collision normally results in the formation of additional debris, increasing the hazard for future missions. The hypervelocity debris effect is studied by retrieving materials from space or by using ground simulation facilities. Simulation facilities, which include the light gas gun and Laser Driven Flyer methods, are used for studying the materials degradation due to debris impact. The impact effect could be accelerated when occurring simultaneously with other space environment components, such as atomic oxygen, ultraviolet, or x-ray radiation. Understanding the degradation mechanism might help in developing materials that will withstand the increasing hazard from the space debris, allowing for longer space missions. The large increase in space debris population and the associated risk to space activity requires significant measures to mitigate this hazard. Most current efforts are being devoted to prevention of collisions by keeping track of the larger debris and avoiding formation of new debris.

Influence of Temperature on Self-Discharge and High-Rate Discharge Characteristics of La-Rich AB5-Based MH Alloy Electrode

2010 ◽  
Vol 654-656 ◽  
pp. 2835-2838 ◽  
Author(s):  
Huai Ying Zhou ◽  
Pei Pei Wang ◽  
Zhong Min Wang ◽  
Rui Ping Zou ◽  
Cheng Yuan Ni
Keyword(s):  
High Rate ◽  
Alloy Electrode ◽  
Discharge Process ◽  
Discharge Characteristics ◽  
Discharge Current Density ◽  
Influence Of Temperature ◽  
Capacity Loss ◽  
Influence Of Temperature On ◽  
Rate Discharge ◽  
High Rate Discharge

The influence of temperature on self-discharge and high-rate discharge characteristics of MmNi3.65(CoAlMn)1.35 alloy electrode has been investigated by way of simulated battery tests. Self-discharge behaviors of the MH electrode were measured using two methods: continuous mode self-discharge and step mode self-discharge. The results indicate that both reversible and irreversible capacity loss of MH electrode are mainly affected by temperature and storage time. When tested at 323K, the gross capacity loss after storage for 4 days is 30.88%, 15.02% at 273K and 20.09% at 303K, respectively. SEM analysis has shown that some needle corrosion products are formed on the surface of MH electrode, especially following storage at high temperature. The efficiency of high-rate discharge process is related closely to its discharge current density (DCD) adopted in tests, discharged capacities decreased with increasing DCD, and the electrode performed good high-rate discharge behavior at 303 K. Cyclic voltammetry (CV) analysis has indicated that near linear relationships between Ip and Scan rate (v) have been observed in the three temperature cases. The calculated values of hydrogen diffusion coefficient (D) within the electrode, are 1.479×10-8 cm2 / s at 273K, 2.437×10-8 cm2 / s at 303K, and 3.156×10-8 cm2 / s at 323K, respectively.

scholarly journals Effects of Maternal Homelessness, Supplemental Nutrition Programs, and Prenatal PM2.5 on Birthweight

2019 ◽  
Vol 16 (21) ◽  
pp. 4154 ◽  
Author(s):  
Jongeun Rhee ◽  
M. Patricia Fabian ◽  
Stephanie Ettinger de Cuba ◽  
Sharon Coleman ◽  
Megan Sandel ◽  
...  
Keyword(s):  
Synergistic Effects ◽  
Fine Particulate Matter ◽  
Black Mothers ◽  
Second Trimester ◽  
Linear Regression Models ◽  
Supplemental Nutrition ◽  
Nutrition Programs ◽  
Wic Participation ◽  
Pollution Exposure ◽  
The Impact

Few studies examined the impact of maternal socioeconomic status and of its combined effects with environmental exposures on birthweight. Our goal was to examine the impact of maternal homelessness (mothers ever homeless or who lived in shelters during pregnancy) and participation in the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) during pregnancy in conjunction with air pollution exposure on birthweight in the Boston-based Children’s HealthWatch cohort from 2007 through 2015 (n = 3366). Birthweight was obtained from electronic health records. Information on maternal homelessness and WIC participation during pregnancy were provided via a questionnaire. Prenatal fine particulate matter (PM2.5) exposures, estimated at the subject’s residential address, were calculated for each trimester. We fit linear regression models adjusting for maternal and child characteristics, seasonality, and block-group-level median household income and examined the interactions between PM2.5 and each covariate. Prenatal maternal homelessness was associated with reduced birthweight (−55.7 g, 95% CI: −97.8 g, −13.7 g), while participating in WIC was marginally associated with increased birthweight (36.1 g, 95% CI: −7.3 g, 79.4 g). Only average PM2.5 during the second trimester was marginally associated with reduced birthweight (−8.5 g, 95% CI: −19.3, 2.3) for a 1 µg/m3 increase in PM2.5. The association of PM2.5 during the second trimester with reduced birthweight was stronger among non-Hispanic Black mothers and trended toward significance among immigrants and single mothers. Our study emphasizes the independent and synergistic effects of social and environmental stressors on birthweight, particularly the potentially protective effect of participating in WIC for vulnerable populations.

Sign in / Sign up

Export Citation Format

Share Document