Discharge Performance Research Articles

Investigation of SDS on Corrosion Behavior and Discharge Performance of AZ31B Magnesium Alloys in Aqueous Magnesium Air Batteries

To address the issue of high self-corrosion rate of Mg anodes in seawater batteries leading to low discharge efficiency, the green inhibitor, sodium dodecyl sulfate (SDS), was utilized to enhance the discharging performance of AZ31B alloy. The addition of SDS in a 3.5% NaCl solution led to a reduction in the corrosion rate of AZ31B alloy due to the formation of S-containing compounds. During the continuous-discharging period, the addition of 0.05 M SDS increased the anodic utilization efficiency from 64% to 81% and the specific energy density of the entire battery elevated from 1280 to 1912 mAh g−1 (an increase of 49%). The enhancement of the discharge performance of AZ31B Mg alloy in a 3.5% NaCl solution by SDS can be attributed to three aspects: reducing the negative difference effect of the Mg alloy, decreasing the accumulation of corrosion products on the surface of the Mg alloy, and promoting a more uniform dissolution of the Mg alloy.

Impact of Harmonic Voltage on the Partial Discharge Properties of Eco-Friendly Nanofluid

The Insulation is crucial in transformers to maintain electrical isolation between components and windings, ensuring safe and efficient operation. Mineral oil acts as both insulation and coolant in transformers. It is a substance that does not naturally degrade and can persist in the environment for an extended period if accidentally released. Therefore, Sunflower oil is used as a substitute for mineral oil. However, harmonic distortion is a common issue in power systems, leading to increased dielectric loss and partial discharge activity, ultimately causing insulation failure and equipment damage. Hence, it is vital to analyze the partial discharge performance of pure Sunflower oil under varying harmonic AC voltages to ensure the reliable operation of electrical devices. The study examines the partial discharge characteristics of a sunflower oil-based nanofluid under harmonic AC voltages, which is a blend of pure sunflower oil and SiO2 nanoparticles. Two nanofluid mixtures were created, one with a 0.01% mass ratio and the other with 0.05% sunflower oil. Various PD characteristics were evaluated, including Partial Discharge significance, starting voltage, duration of increase, maximum amplitude, Phase-Resolved PD sample, and frequency and time graphs of the Partial Discharge signal. All tests were carried out under IEC regulations. A comparison was made between the outcomes of Nano blended sunflower oil and natural sunflower edible oil. Experiments were conducted on partial discharges in Sunflower oil using specific harmonic superimposed AC Voltages, utilizing the third and fifth harmonics. The findings reveal that: a) PDIV value decreases with increasing harmonic order when using AC voltage with superimposed harmonics, b) PD characteristics are closely related to the voltage waveform, and the addition of Silica to sunflower oil results in reduced PD amplitude, pulse duration, and time duration compared to pure sunflower oil.

Effect of electrolyte level on performance and mass transfer of non-aqueous lithium-oxygen battery

To accurately reveal the effect of electrolyte content on mass transfer within lithium-oxygen batteries and their discharge performance, this study utilizes computed tomography(CT) scanning technology and digital reconstruction methods to construct a geometric model of the lithium-oxygen battery cathode that is equivalent to the actual one. Based on the fundamental principles of mass transfer, fluid dynamics, and electrochemistry, a two-dimensional model for the discharge process of lithium-oxygen batteries is established. This model facilitates analysis of various parameters and their influencing factors, including the distribution of reaction products, pore structure, oxygen concentration distribution, battery performance, and overpotential, within the lithium-oxygen battery cathode. The research findings indicate that the deposition of reaction products alters the cathode structure and material transport; lower discharge current density and higher electrolyte levels are conducive to the dispersed deposition of reaction products, thereby reducing the deposition's resistance to internal mass transfer in the cathode.

Advancing zinc-ion batteries: Amorphous V2O5 as a protective layer on Zn anode surface

Recently, Zn-ion batteries (ZIBs) have emerged as prominent solutions for next-generation rechargeable batteries due to abundant Zn resources and the reduced explosion risk associated with aqueous electrolytes. Nonetheless, the low charge–discharge performance of ZIBs due to the corrosive interactions between mildly acidic aqueous electrolytes and Zn anodes, as well as dendrite growth, limit their further application. To mitigate these degradation effects, this study incorporates an amorphous phase V2O5-coated Zn (AVO-Zn) anode into ZIBs. The amorphous phase V2O5 enhances the wettability of the Zn anode and mitigates hydrogen evolution and corrosion, enabling high stability of the anode over 500 h with a low overpotential of 42 mV during symmetric cell analysis. Furthermore, by providing flat Zn plating by increasing the number of nucleation sites to inhibit dendrite formation, the AVO-Zn anode achieves a high energy density of 236 Wh kg−1 at a power density of 270 W kg−1 and good long-term cyclability with a high specific capacity of 136 mAh g−1 after 200 cycles.

Ultrasmall Fe‐Nanoclusters‐Anchored Carbon Polyhedrons Interconnected with Carbon Nanotubes for High‐Performance Zinc‐Air Batteries

The catalytic activity of metal catalyst is closely related to its particle size. Yet, the size effect in electrocatalytic oxygen reduction reaction (ORR), an important reaction for metal‐air batteries and fuel cells, has not been clearly studied. Herein, a two‐step anchoring method is utilized to control the Fe catalyst in forms of nanoparticles (NPs), ultrasmall nanoclusters (NCTs), and isolated atoms as well as stabilized and dispersed by carbon polyhedrons interconnected with carbon nanotubes (CNTs). The uniformly distributed Fe NCTs displays superior ORR performance compared with Fe NPs, isolated Fe atoms, and commercial Pt/C. The brilliant ORR activity of Fe NCTs is a result of its unique electron structure and abundant edge and corner active sites. Due to the porous structure of carbon polyhedrons and high electron conductivity of CNTs, Fe NCTs also delivers an excellent discharge performance in zinc‐air battery with a peak power density of 213.3 mW cm−2 and long‐term stability. In these findings, a new strategy for the design of metal NCTs catalysts applied in various catalytic reactions is opened up.

Giant energy density with ultrahigh efficiency achieved in NaNbO3-based lead-free ceramics with polymorphic antiferrodistortive polar nanodomains

The development of dielectric ceramics with simultaneously high energy-storage density (Wrec) and efficiency (η) for capacitive energy storage poses a significant challenge. Herein, an effective strategy to achieve ultrahigh comprehensive energy-storage performance via designing polymorphic antiferrodistortive polar nanodomains is proposed, successfully realizing a giant Wrec of ∼7.5 J/cm3 with an ultrahigh η of ∼94 % in (0.9-x)NaNbO3-0.1BaZrO3-xBi(Mg0.5Ti0.5)O3 ((0.9-x)NN-0.1BZ-xBMT) lead-free ceramics at x = 0.08. The studied ceramic also exhibits excellent temperature-insensitive charge–discharge performances of high power density ∼204 ± 3 % MW/cm3, high discharge energy density ∼3.7 ± 3 % J/cm3 and fast discharge rate < 60 ns within 25–150 °C. The observation of ex-/in-situ piezoresponse force microscopy and transmission electron microscope reveals that polar nanodomains with multiple antiferrodistortive FE symmetries and diverse scales exhibit dissimilatory transformation behavior into FE microdomains during electric field loading/unloading, being responsible for a low-hysteresis polarization-field response with a near-zero remnant polarization and a high maximum polarization. Meanwhile, optimized bandgap structure and grain morphology contribute to the enhanced ceramic resistivity and conductivity activation energy as well as suppressed leakage current, resulting in significantly improved dielectric breakdown strength. These results demonstrate a feasible strategy for developing novel high-performance dielectric ceramics for high-efficiency capacitive energy storage.

The Effect of Hatch Spacing on the Electrochemistry and Discharge Performance of a CeO2/Al6061 Anode for an Al-Air Battery via Selective Laser Melting

To improve the electrochemical activity and discharge performance of an aluminum-air (Al-air) battery, a commercial 6061 alloy (Al6061) was selected as the anode, and CeO2 was also added inside the anode to enhance its performance. The CeO2/Al6061 composite was prepared using selective laser melting (SLM) technology. The influence of hatch spacing on the forming quality, corrosion resistance, and discharge performance of the anode was studied in detail. The results showed that with an increase in hatch spacing, the density, corrosion resistance, and discharge performance of the anode first increased and then decreased. When the hatch spacing is 0.13 mm, the anode has the best forming quality. At this point, the density reaches 98.39%, and the self-corrosion rate (SCR) decreases to 2.596 × 10−4 g·cm−2·min−1. Meanwhile, the anode exhibits its highest electrochemical activity and discharge voltage, which is up to −1.570 V. The change in anode performance is related to the defects generated during the SLM forming process. For samples with fewer defects, the anode can dissolve uniformly, while for samples with more defects, the electrode solution is prone to penetrate the defects, causing uneven corrosion and reducing electrochemical and discharge activity.

Study on the Influence of Chord Length and Frequency of Hydrofoil Device on the Discharge Characteristics of Floating Matter in Raceway Aquaculture

To investigate the influence of the chord length and frequency of an oscillating hydrofoil device on the discharge characteristics of floating particulate matter, in this study, we take raceway aquaculture as an example and systematically compare and analyze the flow field characteristics of the hydrofoil device with different chord lengths and frequencies, as well as the sewage discharge performance of the raceway based on Computational Fluid Dynamics (CFD). The results indicate that in the particulate matter discharge process of raceway aquaculture, when the chord length and motion frequency of the hydrofoil device are 0.1 W (W is the width of the raceway) and 1.0 Hz, respectively, the anti-Karman vortex streets produced by the hydrofoil device are less affected by the wall, the flow field is the most uniform, the particulate matter discharge performance is the best, and the final floating particulate matter discharge rate reaches up to 99.09%. Adjusting the chord length of the hydrofoil can effectively ameliorate flow field reflux issues, enhancing the uniformity and flow performance of the flow field. When the chord length is 0.1 W, the uniformity of the flow field is optimal. When the chord length is 0.2 W, the flow performance of the flow field is superior. Increasing the frequency enhances the flow performance of the flow field, with an average increase of 0.1 Hz in motion frequency leading to a 19.42% improvement in the average velocity at the outlet. Based on this, we recommend the use of a hydrofoil device with a chord length of 0.1 W and a motion frequency of 1.0 Hz in the raceway aquaculture system to achieve optimal particulate matter discharge performance, providing a theoretical basis and practical guidance for using hydrofoil devices to improve the efficiency of floating particulate matter treatment in raceway aquaculture environments.

Enhanced catalytic activity and durability of Ru–Fe alloy-modified Sr1.95Fe1.5Mo0.5O6-δ nanostructured symmetric electrode

The stable and advanced catalytic symmetrical electrode material can reduce the number of electrode exchange in hydrocarbon fuel and extend the service life of symmetrical solid oxide fuel cells (SSOFCs). In this study, Sr1.95Fe1.45Ru0.05Mo0.5O6-δ (SFRM) perovskites were developed and applied as both fuel and air electrode materials for SSOFCs for the first time. The peak power density (PPD) of SSOFC using SFRM electrodes is 583.6 mW cm−2, which is higher than that of SSOFC using SFM electrodes at 800 °C. Additionally, with an increase in reduction time, the maximum power density further increases by 20%–804.9 mW cm−2 with the exsolution of Ru–Fe antiparticles. Importantly, Ru doping results in a significant decrease in the size of exsolved nanoparticles and leads to a larger specific surface area. In the atmosphere of pure methane, Ru doped SFM increased from 130.9 to 185.1 W cm−2 compared with pure phase, and the discharge performance of SFRM electrode at 850 °C was more stable than that of SFM electrode. Thus, SFRM electrodes present a promising and viable option for enhancing the performance of SSOFCs.

Post-resuscitation pneumothorax: retrospective analysis of incidence, risk factors and outcome-relevance

BackgroundPneumothorax may occur as a complication of cardiopulmonary resuscitation (CPR) and could pose a potentially life-threatening condition. In this study we sought to investigate the incidence of pneumothorax following CPR for out-of-hospital cardiac arrest (OHCA), identify possible risk factors, and elucidate its association with outcomes.MethodsThis study was a retrospective data analysis of patients hospitalized following CPR for OHCA. We included cases from 1st March 2014 to 31st December 2021 which were attended by teams of the physician staffed ambulance based at the University Medical Centre Graz, Austria. Chest imaging after CPR was reviewed to assess whether pneumothorax was present or not. Logistic regression analysis was performed to identify factors for the development of pneumothorax relevant and to assess its association with outcomes [survival to hospital discharge and cerebral performance category (CPC)].ResultsPneumothorax following CPR was found in 26 out of 237 included cases (11.0%). History of obstructive lung disease was significantly associated with presence of pneumothorax after CPR. This subgroup of patients (n = 61) showed a pneumothorax rate of 23.0%. Pneumothorax was not identified as a relevant factor to predict survival to hospital discharge or favourable neurological outcome (CPC1 + 2).ConclusionsPneumothorax may be present in greater than one in ten patients hospitalized after CPR for OHCA. Pre-existent obstructive pulmonary disease seems to be a relevant risk factor for development of post-CPR pneumothorax. ClinicalTrials.gov ID: NCT06182007 (retrospectively registered).Trial Registration: NCT06182007 (retrospectively registered)

Electrochemical Performance of Deposited LiPON Film/Lithium Electrode in Lithium-Sulfur Batteries.

This paper presents a composed lithium phosphate (LiPON) solid electrolyte interface (SEI) film which was coated on a lithium electrode via an electrodeposit method in a lithium-sulfur battery, and the structure of the product was characterized through infrared spectrum (IR) analysis, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), environment scanning electron microscope (ESEM), etc. Meanwhile, the electrochemical impedance spectrum and the interface stability of the lithium electrode with the LiPON film was analyzed, while the coulomb efficiency and the cycle life of the lithium electrode with the LiPON film in the lithium-sulfur battery were also studied. It was found that this kind of film can effectively inhibit the charge from transferring at the interface between the electrode and the solution, which can produce a more stable interface impedance on the electrode, thereby improving the interface contact with the electrolyte, and effectively improve the discharge performance, cycle life, and the coulomb efficiency of the lithium-sulfur battery. This is of great significance for the further development of solid electrolyte facial mask technology for lithium-sulfur batteries.

Multi-Objective Optimization for the Forming Quality of a CeO2/Al6061 Alloy as an Aluminum–Air Battery Anode Manufactured via Selective Laser Melting

To improve the discharge performance of aluminum–air batteries, CeO2/Al6061 composites were prepared as an anode using selective laser melting (SLM). Response surface methodology (RSM) was employed, and the test results were linearly fitted. A prediction model for the forming quality of the composite anode was established, and the reliability of the model and the interaction between process parameters were explored based on variance analysis and significance testing. On this basis, with corrosion potential, self-corrosion rate, and discharge voltage as optimization objectives, the optimal solution set of the SLM forming CeO2/Al6061 anode process parameter was solved through a genetic algorithm, and experimental verification was conducted. The results indicate that the optimal process range for the forming quality and various properties of composite materials is laser power of 265~285 W, scanning speed of 985~1025 mm/s, and scanning spacing of 0.116~0.140 mm. The optimized process parameters were selected for reliability testing, and the errors were all within 3.0%, verifying the accuracy and reliability of the model.

Thermal Battery Multi-Defects Detection and Discharge Performance Analysis Based on Computed Tomography Imaging

To address the typical structural defects that are prone to occur during the preparation and storage processes of thermal battery, experiments of battery image acquisition were designed based on X-ray computed tomography system. An improved Yolov5s network was employed to achieve high-precision automatic detection of typical defects. Through the discharge experiment of thermal battery, discharge performance curves of normal batteries and three defective batteries were constructed. The impact and mechanisms of different defects on the discharge performance were analyzed based on the voltage curve. By designing an automatic stitching scheme, the phenomenon of interlayer information overlap caused by the increase of cone angle in digital radiography images was suppressed. To address the issues of low image contrast and limited defect data in thermal battery imaging, the defect dataset was expanded using the designed image preprocessing steps and improving the contrast of the images. For subtle defects that are difficult to identify, the introduced multi-head self-attention mechanism in Transformer and the use of Focal Loss instead of cross-entropy loss function were employed to improve the recognition accuracy of subtle defects while ensuring the detection speed. The comparative experiment shows that the improved network model has higher recognition accuracy compared to Faster R-CNN, SSD, Cascade R-CNN, EfficientDet and the original Yolov5s network. The recognition accuracy of typical defects in thermal batteries can reach 98.7%.

Improving Discharge Predictions in Ungauged Basins: Harnessing the Power of Disaggregated Data Modeling and Machine Learning

AbstractCurrent machine learning methods for discharge prediction often employ aggregated basin‐wide hydrometeorological data (lumped modeling) for parametric and non‐parametric training. This approach may overlook the spatial heterogeneity of river systems and their impact on discharge patterns. We hypothesize that integrating spatiotemporal hydrologic knowledge into the data modeling process (distributed/disaggregated modeling) can improve the performance of discharge prediction models. To test this hypothesis, we designed experiments comparing the performance of identical Long Short‐Term Memory Recurrent Neural Network (LSTM‐RNN) models forced with either lumped or distributed features. We gather meteorological forcing and static attributes for the Mackenzie basin in Canada‐ a large and unique basin. Importantly, discharge performance is assessed out‐of‐sample with k‐fold replication across gauges. Training LSTMs with disaggregated data significantly improved model accuracy. Specifically, there was a 9.6% increase in the mean Nash‐Sutcliffe Efficiency and a 4.6% increase in the mean Kling‐Gupta Efficiency, indicating a better agreement between predicted and actual observations in terms of mean, variability, and correlation. These experiments and results demonstrate the importance of integrating topologically guided geomorphologic and hydrologic information (distributed modeling) in data‐driven discharge predictions.

Kinetic investigation of discharge performance for Xe, Kr, and Ar in a miniature ion thruster using a fast converging PIC-MCC-DSMC model

Abstract The present work develops a full particle-based model that couples the particle-in-cell plus Monte Carlo collision (PIC-MCC) simulation for plasma dynamics and the direct simulation Monte Carlo (DSMC) method for neutral dynamics in a synergistic iterative manner. This new model overcomes the slow convergence issue in the conventional direct coupling approach caused by the disparity of the time scales between the plasma and neutral dynamics. This model is applied to simulate the behavior of xenon (Xe) and its potential alternatives, krypton (Kr) and argon (Ar), in the discharge chamber of a miniature direct current (DC) ion thruster. The results show that a stable discharge is difficult to achieve for Kr and Ar under the operating conditions optimal for Xe. While increasing the discharge voltage can effectively improve the stability of discharge for Kr and Ar, other common strategies such as changing the magnetic field strength, propellant flow rate, and cathode current are not successful. The propellant utilization efficiency and discharge efficiency are affected by both discharge voltage and propellant flow rate. A maximum utilization efficiency and an optimal discharge efficiency are observed for all three propellants, with the values decreasing in the order of Xe, Kr, and Ar. Moreover, the discharge voltage corresponding to the optimal efficiency is inversely proportional to the square root of the propellant mass, indicating that the ion diffusional loss to the wall, rather than the ionization energy, is the dominant factor affecting the discharge performance for alternative propellants in a miniature DC thruster.

Role of combinative In and Sm additions in tailoring the discharge performance of extruded AZ31 alloys as anodes for seawater batteries

The discharge behaviors of AZ31 alloys, modified by the addition of In and Sm elements in conjunction with equal channel angular pressing (ECAP) processing, were systematically explored. The incorporation of In suppressed the formation of cathodic second phases. In contrast, Sm promoted the precipitation process and therefore led to higher microstructure uniformity following ECAP processing. The solid-solution In contributed to the activated dissolution of Mg matrix and the inhibited hydrogen evolution during discharge, while Sm was beneficial for the uniform dissolution and the alleviation of chunk effect. The results indicated that the 12-pass ECAP processed AZ31-In-Sm anode revealed the most enhanced discharge performance with a discharge voltage of 0.889 V and a utilization of 66.94% at 100 mA cm−2. This improvement can be primarily attributed to the combined effects of the decreased precipitations of cathodic phases by In addition and the enhanced microstructure homogeneity by Sm addition, collaborated with significant microstructure refinement.

Nano-enhanced phase change materials for temperature regulation of a LiFePO4 lithium-ion pouch cell using CFD simulation

The temperature control of Lithium-ion (Li-ion) cells plays a crucial role in enabling high current discharge performance. To address this, the present study explores the use of RT35 phase change material (PCM) and single-walled carbon nanotubes (SWCNT) as an additive approach to regulate the temperature of LiFePO4 Li-ion cells. By employing computational fluid dynamics (CFD), incorporating buoyancy force and a turbulent approach, an unsteady problem was simulated to investigate the effects of key parameters such as SWCNT concentration and PCM thickness. Notably, SWCNT addition exhibits a double effect, reducing liquid PCM volume and modifying temperature profiles. The average melting fraction at SOC = 100 % decreased from 100 % to 88 % with increasing PCM thickness from 9δ to 17δ, while it reduced the battery temperature by 3394 K to 331 K. Additionally, the impact of SWCNT volume fraction is most pronounced at 0.02, with similar effects observed at 0.04 and 0.06.

Relatively low temperature defluorination and carbon coating in CFx by dimethyl silicone oil/polyethylene glycol for enhancing performance of lithium primary battery

Because of the presence of electrochemically inactive C-F2 bond and poor electronic conductivity of C-F, the discharge performance of lithium fluorocarbon (Li/CFx) batteries is limited, despite their extensive use in commercial fields. In this study, dimethyl silicone oil/polyethylene glycol was adopted to improve the performance of CFx through relatively low temperature (350 °C) defluorination and carbon coating. The uniform mixing of dimethyl silicone oil with CFx and the subsequent gas–solid reaction enables mild defluorination, transforming C-F2 into semi-ionic C-F with high conductivity. Furthermore, this dimethyl silicone oil/ polyethylene glycol treated CFx under 350 °C prevent the thermal decomposition of C-F during both of the defluorination and carbon coating process, resulting in improving the electrical performance and capacity protection of CFx. Specifically, the modified CFx cathode exhibits a 2.7 V discharge platform, a discharge capacity of 859.1 mAh/g and the energy density of 1889.7 Wh kg−1 at 0.01C. This approach allows for large scale adjustments of CFx with excellent performance, making it easy to industrialization.

Technical considerations for sampling ballast water to determine compliance with discharge performance standards

Technical considerations for sampling ballast water to determine compliance with discharge performance standards

A Shared Anode Flow Field for Direct Methanol Fuel Cell with Enhanced Performance and Decreased Volume

Low‐volume power density remains a significant barrier to the portable application of direct methanol fuel cell (DMFC). Herein, a shared anode flow field (SAFF) structure is introduced in an active DMFC to reduce stack volume and improve discharge performance. The differences in discharge performance between the bi‐cell with SAFF and the bi‐cell with traditional anode flow field (TAFF), coupled with the effect of operating conditions on performance, are investigated by polarization curve, electrochemical impedance spectra, and voltage versus time curves. The results show that the SAFF structure enhances anode mass transfer, resulting in an improvement in peak power density and voltage stability of the bi‐cell compared to the TAFF structure. In addition, the bi‐cell with SAFF achieves its highest peak power density at a lower methanol concentration, alleviating the methanol crossover caused by high concentration. The SAFF structure is an attractive choice for DMFC portable applications.