Discharge Profiles Research Articles

New Signal Processing-Based Methodology for Optimal Feature Selection of Corona Discharges Measurement in HVDC Systems

This article presents a new method based on the combination of digital signal processing parameters for the selection of optimal characteristics of corona discharges in HVDC systems, particularly for linearization of the discharge model for applications that require a simplified computational approach. The proposed method implements a new metric from the coefficient of variation, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CV_STFT</i> , based on the short-time Fourier transform (STFT) and the Hinkley criterion to measure the spectral variability and determine the corona discharge profile in different situations. An experimental analysis was performed by applying voltages between ± 30kV and ± 100 kV in a conductor, and electrical current signals proportional to the corona effect were collected through a data acquisition system. The results indicated that the application of the new method was successful in quantifying, in a simple way, the percentage of growth of corona discharges as a function of the voltage applied within the range of 40-80 kHz. Moreover, it showed 90 %, 91 %, 92%, 97%, 89%, 92%, and 93% of reliability in calculating the root-mean-square deviation (RMSD) based on approximation by a linear model. The frequency band resulting from this study proved to be favorable to establishing a threshold for the percentage of corona discharge growth according to its profile or condition of application, indicating this information may be useful in the construction of mobile devices with low consumption and computational performance, meeting the demands of Industry 4.0 and the Internet of Things.

Energy-Efficient Trajectory Design of a Multi-IRS Assisted Portable Access Point

In this article, we propose a framework for energy efficient trajectory design of an unmanned aerial vehicle (UAV)-based portable access point (PAP) deployed to serve a set of ground nodes (GNs). In addition to the PAP and GNs, the system consists of a set of intelligent reflecting surfaces (IRSs) mounted on man-made structures to increase the number of bits transmitted per Joule of energy consumed measured as the global energy efficiency (GEE). The GEE trajectory for the PAP is designed by considering the UAV propulsion energy consumption and the Peukert effect of the PAP battery, which represents an accurate battery discharge profile as a non-linear function of the UAV power consumption profile. The GEE trajectory design problem is solved in two phases: in the first, a path for the PAP and feasible positions for the IRS modules are found using a multi-tier circle packing method, and the required IRS phase shift values are calculated using an alternate optimization method that considers the interdependence between the amplitude and phase responses of an IRS element; in the second phase, the PAP flying velocity and user scheduling are calculated using a novel multi-lap trajectory design algorithm. Numerical evaluations show that: neglecting the Peukert effect overestimates the available flight time of the PAP; after a certain threshold, increasing the battery size reduces the available flight time of the PAP; the presence of IRS modules improves the GEE of the system compared to other baseline scenarios; the multi-lap trajectory saves more energy compared to a single-lap trajectory developed using a combination of sequential convex programming and Dinkelbach algorithm.

Electrochemical modeling, Li plating onsets and performance analysis of thick graphite electrodes considering the solid electrolyte interface formed from the first cycle

Based on a crack dominated solid electrolyte interface (SEI) resistance, an electrochemical model considering the SEI formed from the first cycle is established to investigate the comprehensive influence of electrode thickness, solid volume fraction and C-rate on the performance of thick graphite electrodes. Reasonable agreement is obtained for the simulated and measured charge and discharge profiles of Li/graphite cells including the first cycle. The periodic evolution of SEI film resistance during the cycles can be well interpreted by the mechanism based on the growth of SEI crack. The potential drop over SEI is found to contribute little to the polarization during Li inter- and deintercalation, and the electrode porosity reduction caused by SEI growth has larger effect for thick electrode than traditional thin electrode. The cell voltages, total potential drop of the electrode, state of charge and ratio of SEI capacity to the total capacity at the onsets of Li plating are analyzed. A linear relationship is developed for the Li plating onset voltages with the increasing of electrode thicknesses, solid volume fractions and C-rates. Finally, the performance of Li/graphite cells with electrode thicknesses (δ) ranging from 100 μm to 500 μm, solid volume fractions (εs) ranging from 0.35 to 0.6 and C-rates ranging from 0.05C to 0.5C is simulated and compared. The ionic migration limitation is aggravated by the growth of SEI for electrodes thicker than 300 μm as the solid volume fraction increases. The maximal areal capacity appears around δ = 500 μm and εs = 0.4, with a rate performance of 13.8 mAh cm−2, 13.6 mAh cm−2 and 13.1 mAh cm−2 at 0.1C, 0.2C and 0.5C, respectively.

Modeling the volumetric expansion of the lithium-sulfur battery considering charge and discharge profiles

As an alternative battery technology to the established lithium-ion battery, the lithium–sulfur battery shows great potential due to its greater energy density, safety and possible lower material costs. In the next few years 500-600Wh kg-1 could be implemented. However, there are still challenges in the commercialization and condition monitoring of the battery. Conventional methods of the lithium-ion technology, such as state of charge prediction via open circuit voltage (the discharge curve/charge curve has two plateaus), as well as coulomb counting are ineffective for the lithium-sulfur battery. However, due to the continuous volumetric change during battery operation, this could be a possible approach to monitor and predict the condition of the battery. Therefore, this paper presents a model that determines the volumetric change as a function of a constant discharge/charge profile. The influence of the selected values is investigated by a parameter variation. The parameter set for the model is further characterized by a computer tomography measurement. The simulation model is verified by literature and measurement data. This modeling approach could influence the development of a future battery management system for lithium–sulfur battery.

State of health estimation of lithium-ion batteries with a temporal convolutional neural network using partial load profiles

An accurate aging forecasting and state of health estimation is essential for a safe and economically valuable usage of lithium-ion batteries. However, the non-linear aging of lithium-ion batteries is dependent on various operating and environmental conditions wherefore the degradation estimation is a complex challenge. Moreover, for on-board estimations where only limited memory and computing power are available, a state of health estimation algorithm is needed that is able to process raw sensor data without complex preprocessing. This paper presents a data-driven state of health estimation algorithm for lithium-ion batteries using different segments of partial discharge profiles. Raw sensor data is directly input to a temporal convolutional neural network without the need of executing feature engineering steps. The neural network is able to process raw sensor data and estimate the state of health of battery cells for different aging and degradation scenarios. After executing Bayesian hyperparameter tuning together with a stratified cross validation approach for splitting the training and test data, the achieved generalized aging model estimates the state of health with an overall root mean squared error of 1.0%.

WP Nanocrystals on N,P Dual-Doped Carbon Nanosheets with Deeply Analyzed Catalytic Mechanisms for Lithium–Sulfur Batteries

WP Nanocrystals on N,P Dual-Doped Carbon Nanosheets with Deeply Analyzed Catalytic Mechanisms for Lithium–Sulfur Batteries

Preparation of xLiMnPO4-Li3V2(PO4)3/C composite cathode materials from the novel Mn2V2O7/MnV2O6 precursors

The composite cathode materials xLiMnPO4-Li3V2(PO4)3/C (x = 1, 2) are prepared from Mn2V2O7 and MnV2O6 precursors with a simple solid-state method. XRD results show that the composites consist of orthorhombic LiMnPO4 and monoclinic Li3V2(PO4)3 phases, without any other impurity phases. The average particle size and agglomeration degree of the materials are reduced with Li3V2(PO4)3 compounded into LiMnPO4. Electrochemical performance tests manifest that the specific discharge capacities of xLiMnPO4-Li3V2(PO4)3/C (x = 1, 2) at various C-rates are much higher than those of LiMnPO4/C. The discharge profiles of both composites contain three voltage plateaus of 3.62, 3.68 and ∼ 4.05 V. Especially, 2LiMnPO4-Li3V2(PO4)3/C delivers the first specific capacity of 159.6, 133.5 and 112.2 mAh/g at 0.1C, 2C and 5C, respectively, and exhibits excellent cyclic stability.

PROPOSITION OF AN EXTENSION TO THE PEUKERT’S LAWMODEL APPLIED TO THE PREDICTION OF THE BATTERIESLIFETIME

Accurate prediction of the rechargeable battery lifetime is important for the optimization of the use of different types of mobile devices in the present time. Many of them use simple analytical models for this task, such as Peukert's Law model. This paper aims to evaluate the accuracy of battery lifetime prediction, from an extension of Peukert's Law. The original and extended models are evaluated by comparing the results of computational simulations and a wide set of experimental data obtained from a test platform under scenarios of constant and variable current discharges, the extended model is also compared with an accurate model of the literature, i.e., the Rakhmatov and Vrudhula's diffusion model. For lithium-ion polymer batteries, the proposed extended model is accurate, it produced an average error of 1.07 \% in the prediction of battery lifetime for discharges with constant current profiles and an average error of 2.57 \% for variable discharge profiles that simulate the power drain of a smartphone used for a variety of everyday applications.

Proton Exchange Membrane for Iron Air/Flow Battery Application

Iron air/redox flow battery is the next promising battery system that can bridge the drawbacks of a static battery, at least in medium to high storage systems, due to the distinguishing difference from its static counterpart. It comes with the main advantages: the high current discharge and a flowing electrolyte, which can significantly suppress the formation of dendrite and passivation without imposing permanent damage to the cell structure. Iron, the fourth most abundant metal on the earth's crust, comes at a lower cost and requires less corrosion protection.This technology has received less attention than others due to overpotential/overvoltage and high Hydrogen evolution reaction on the anode. Different promising approach has been explored to improve the cycling stability of iron air batteries; by adding different electrolyte additives to suppress passivation and hydrogen evolution during discharge, improving the air cathode design by including dual or bifunctional electrocatalyst, and recent modification of the anode has helped realize a better iron air battery by facilitating a high surface area iron electrode using nanosized iron particle, and these create more electrode available to electrolyte and further adding a suitable additive to the electrode and electrolyte and increase charge capacity.Nonetheless, the battery working components begin to degrade as they interact; these cannot be stopped as batteries are consumable objects, but they can be delayed by improving the membrane separator's physical-chemical properties like conductivity, swelling ratio, selectivity, and membrane stability. Membrane's critical role aid in the improvement of the battery performance by separating the air cathode and metal anode electrode compartments to prevent short-circuiting, facilitate proton transfer, act as an electron insulator, and prevent fuel crossover, therefore improving the battery cycle life. The presentation will cover the basic working principle of the iron-air/redox flow battery and its prospective future in grid application and a brief report on the role of composite proton exchange membrane and their influence on cycle stability. ReferencesSakai, T., Inoishi, A., Ogushi, M., Ida, S., & Ishihara, T. (2016). Characteristics of fe-air battery using Y2O3-stabilized-ZrO2 electrolyte with Ni–Fe electrode and Ba0.6La0.4CoO3-δ electrode operated at intermediate temperature. Journal of Energy Storage, 7, 115-120.Abbasi, A., Hosseini, S., Somwangthanaroj, n., Cheacharoen, R., Olaru, S., & Kheawhom, S. (2020). Discharge profile of a zinc-air flow battery at various electrolyte flow rates and discharge currents. Scientific Data, 7(1), 196.Leung, P., Li, X., De León, C. P., Berlouis, L., Low, C. J., & Walsh, F. C. (2012). Progress in redox flow batteries, remaining challenges and their applications in energy storage. Rsc Advances, 2(27), 10125-10156.Karomah, A. (2021). Iron-air batteries: A breakthrough in green energy. . Retrieved 17 march, 2022, from https://www.azom.com/article.aspx?ArticleID=20872.McKerracher, R., Ponce de León, C., Wills, R. G. A., Shah, A., & Walsh, F. (2014). A review of the Iron–Air secondary

Composite TiO2/GeO2 for Higher Performance Inverse Opal Lithium-Ion Battery Electrodes

With the ever-growing technology industry and the need for more sustainable energy, the race to develop better, more efficient, renewable materials for lithium ion batteries is at the forefront of research. Metal oxide materials for use as electrodes in lithium batteries have been promising in recent years, transition metal oxides are favourable due to their low cost and nanostructured metal oxides exhibit encouraging electrochemical properties.1-2 Photonic crystal structures, more specifically inverse opal (IO) structures, are porous, highly interconnected structures which have proven to have advantageous benefits such as increased surface area and lower ion diffusion distances.3 In this work we combine TiO2 and GeO2 in solution phase in two ratios, 2:1 and 5:1 in favour of TiO2. Titanium oxides have high working potentials, higher than graphite which is most commonly used today. TiO2 has previously shown excellent long life cyclability and has shown little structural strain during the lithiation/delithiation process.4 Germanium has a high theoretical capacity of 1384 mAh/g and high electrical conductivity however it is expensive for use as an anode.5 Previous reports have shown that by nano-structuring GeO2 into an inverse opal structure, it can behave like pure germanium during cycling beyond the initial reduction and lithitation cycles.6 By combining both materials, we were able to achieve high capacity values for both ratios, 3 times the capacity of titanium IOs on their own. Work is ongoing to investigate the optimal cost to benefit ratio of the TiO2/GeO2 composites. Initial capacity results showcase high capacity retention and voltage stability. Reddy, M. V.; Subba Rao, G. V.; Chowdari, B. V. R., Metal Oxides and Oxysalts as Anode Materials for Li Ion Batteries. Chemical Reviews 2013, 113 (7), 5364-5457.Wu, H. B.; Chen, J. S.; Hng, H. H.; Wen Lou, X., Nanostructured metal oxide-based materials as advanced anodes for lithium-ion batteries. Nanoscale 2012, 4 (8), 2526-2542.Armstrong, E.; O'Dwyer, C., Artificial opal photonic crystals and inverse opal structures – fundamentals and applications from optics to energy storage. Journal of Materials Chemistry C 2015, 3 (24), 6109-6143.McNulty, D.; Carroll, E.; O'Dwyer, C., Rutile TiO2 Inverse Opal Anodes for Li-Ion Batteries with Long Cycle Life, High-Rate Capability, and High Structural Stability. Advanced Energy Materials 2017, 7 (12), 1602291.Zhang, Q.; Chen, H.; Luo, L.; Zhao, B.; Luo, H.; Han, X.; Wang, J.; Wang, C.; Yang, Y.; Zhu, T.; Liu, M., Harnessing the concurrent reaction dynamics in active Si and Ge to achieve high performance lithium-ion batteries. Energy & Environmental Science 2018, 11 (3), 669-681.McNulty, D.; Geaney, H.; Buckley, D.; O'Dwyer, C., High capacity binder-free nanocrystalline GeO2 inverse opal anodes for Li-ion batteries with long cycle life and stable cell voltage. Nano Energy 2018, 43, 11-21. Figure 1. (a) SEM image of a TiO2/GeO2 inverse opal (b) SEM image of TiO2/GeO2 IOs with EDX mapping overlay indicating position of titanium (green) and germanium (red). (c) and (d) Charge discharge profiles at 150 mA/g for the first 100 cycles for the 2:1 ratio and 5:1 ratio respectively.(e) Rate capability test for both ratios with specific currents ranging from 75 mA/g-450 mA/g. Figure 1

Development of MoO3-Based Proton Batteries

Aqueous rocking chair batteries have attracted attention as highly safe and inexpensive secondary batteries. Lithium and sodium ions have mostly been used as the mobile ions, whereas proton systems with potentially the highest mobility have rarely been reported. Recently, research on proton batteries has been conducted using concentrated sulfuric acid solutions as the electrolyte that can assist high-rate performance.[1] Stability under concentrated acidic conditions is required for the electrode materials, as well as the capability of proton accommodation. MoO3 has been reported as a stable negative electrode material for aqueous proton batteries,[2] while few positive electrode materials are known except for bulky organic[3] and Prussian-blue materials[4]. For achieving high energy density and long life, oxide positive electrode materials are desirable. Here we propose the application of MoO3 as the positive electrode material by optimizing the operating composition range. The potential values shown below are all shown versus SHE (actually measured with Ag/AgCl).MoO3 showed a discharge profile at around 0.5 V with the maximum capacity of ca. 100 mAh g-1, as shown in the figure. This potential is sufficiently more positive than the redox potential of protonated MoO3 of around -0.3 V as the negative electrode. With the aid of operando X-ray diffraction analysis, it turned out that the discharge regions at 0.5 V and 0.4 V are respectively associated with a biphasic transition of MoO3/phase I (ca. 0 < x < 0.3 in H x MoO3) and a single-phase reaction of phase I (ca. 0.3 < x < 0.5 in H x MoO3). Deep discharging beyond this range results in the coexistence of phase I and phase III (ca. 0.5 < x < 1.5 in H x MoO3) and the proton extraction from phase III leads to the formation of phase II or phase IIa with its discharging potential of 0.0 V. Structural calculation based on the density function theory is employed to clarify the origin of this irreversible phase transition behavior. Different proton sites between these phases seem to be responsible.An aqueous proton battery with a 7 mol dm–3 sulfuric acid electrolyte was constructed with H-inserted MoO3 and MoO3as the negative and positive electrodes, respectively, and was successfully discharged and charged repeatedly, with the operating voltage of ca. 0.6 V, indicating the launch of aqueous proton battery composed of oxide active materials. Reference s : [1] J. Li, H. Yan, C. Xu, Y. Liu, X. Zhang, M. Xia, L. Zhang, J. Shu, Nano Energy, 89 (2021) 106400.[2] X. Wang, Y. Xie, K. Tang, C. Wang, C. Yan, Angew. Chem. Int. Ed., 57 (2018) 11569.[3] X. Wang, J. Zhou, W. Tang, Energy Storage Mater., 36 (2021) 1.[4] X. Wu, J. J. Hong, W. Shin, L. Ma, T. Liu, X. Bi, Y. Yuan, Y. Qi, T. W. Surta, W. Huang, J. Neuefeind, T. Wu, P. A. Greaney, J. Lu, X. Ji, Nat. Energy, 4 (2019) 123. Figure 1

Investigation of Cellulose-Based Separators for Secondary Lithium Metal Batteries

Lithium-ion batteries (LIBs) have been the predominant energy storage technology for a variety of applications such as portable electronic devices and wireless power tools. However, the rising demand for emerging technologies such as long-range electric vehicles and grid-level energy storage and delivery has drastically increased the necessity for low-cost LIBs with enhanced performance and safety.Improvements in the modern LIB technology can be achieved through improvements in different, individual components of the battery. Among the key components of the battery, the separator plays a vital role. To date, polypropylene (PP)/polyethylene (PE) membranes have been used as separators in LIBs due to their desired electrochemical stability. However, these separator materials suffer from low thermal stability, which results in their deformation or decomposition at elevated temperatures upon high charging rates1. A dangerous consequence of this material degradation is an electrical short, leading to an aggressive discharge of the battery and subsequent fire. Moreover, PP/PE separators possess relatively low electrolyte wettability and an expensive and eco-unfriendly fabrication process. Hence, alternative separator materials for future LIB technology are indispensable.Among alternative separator materials, cellulose is a promising candidate2. Cellulose is derived from biomass which is one of the most abundant and renewable resources on Earth. It also is non-toxic and has high mechanical and chemical stability. Additionally, with an initial decomposition temperature of 270°C, cellulose offers a major advantage in thermal stability compared to its polymeric competitors3. The thermal and electrochemical stability, electrolyte wettability, and performance of cellulose-based separators in LIBs have been studied3,4. However, those reports mostly consider the conventional LIB electrode materials– Li transition metal oxide and graphite; and focus on the separator/electrolyte compatibility. Therefore, to be considered for future generations of high-performance Li-based batteries, cellulose-based separators must be investigated in batteries with new electrode chemistries.This work presents new insights on the interaction of cellulose-based separator and metallic Li – the leading candidate for future anodes. Coin cells were prepared using various cathode materials, Li metal anode, and a commercial cellulose-based separator. The cycling performance of the cells was tested at different C rates. Results were compared with the cycling performance of the coin cells with similar electrodes but a commercial PP/PE separator. Comparable discharge profiles were observed in the two groups of cells, but the cellulose separator hampered the charging process. Additional electrochemical analysis suggested an undesired interaction between the cellulose-based separator and metallic Li. To further understand this interaction, various protective coatings on the separator were investigated, the results of which suggest a mechanical degradation in the cellulose separator during cycling and consequently a soft short. These results are expected to provide a new understanding regarding the stability of cellulose-based separators in Li metal-containing batteries, which can help with their implementation in the next generation of Li-based batteries with enhanced performance and safety.

(Digital Presentation) Cost-Effective Processing of Nickel-Rich Layered Cathodes for Li Batteries

The layered structured cathode material can provide a higher capacity and stable cycle retention, which is a desired property for lithium-ion batteries. Among them, NMC composed of Ni, Mn and Co as transition metals is considered a promising positive electrode. However, because Co is slightly toxic and an expensive strategic resource, reducing the Co content and maintaining the capacitance and cycle stability are the objectives of this study.In this study, LiNi0.8Mn0.1Co0.1O2 were investigated. Adjust the amount of Li2CO3 and the temperature of calcination to control the size of the crystal grains to achieve better retention. The value of the I(003) and I(104) ratio in XRD pattern represent cation mixing in layered structure. And this parameter is closely related to its electrochemical properties. Discussion will be carried out based on the results of XRD analysis and the charge–discharge profiles and cycling performance.The layered structured cathode material may provide a high capacity and stable cycle retention, which is a desired property for lithium-ion batteries. Among them, NMC composed of Ni, Mn and Co as transition metals is considered a promising positive electrode. However, because Co is slightly toxic and an expensive strategic resource, reducing the Co content and maintaining high capacity and cycle stability are the objectives of this study. In addition, the fabrication of NMC adopting single-crystal (grain size: 1~6 mm) process tends to give better long-term performance than ones with particles in nanometer range.In this study, LiNi0.8Mn0.1Co0.1O2 (NMC811) with substitution of Ni/Mn for Co were selected as the Ni-rich layered cathode investigated. Due to the low melting point of Li2CO3, the heating temperature/time of powder mixture become crucial to control the adequate grain size of to achieve better retention. The value of the I(003) and I(104) ratio in XRD pattern represent cation mixing in layered structure. And this parameter is closely related to its electrochemical properties. Discussion will be carried out based on the results of XRD analysis and the charge–discharge profiles and cycling performance.

A high-purity AgO cathode active material for high-performance aqueous AgO–Al batteries

The aqueous divalent silver oxide (AgO)-aluminum (Al) batteries have garnered international attention due to the advantages of high safety, high specific energy, and environmental friendliness. However, the low purity of the AgO used as the cathode material shortens the battery's storage life and causes two voltage plateaus during discharge. Herein, we employ a quick and efficient approach to make AgO for aqueous AgO–Al batteries' cathode active material. The outcomes exhibit the successful production of high purity AgO with good thermal stability. The prepared AgO cathode additionally displays an excellent specific capacity of 394.7 mAh g−1, and the plateau of the discharge profile is closed to 1.7 V at the current density of 500 mA cm−2, taking advantage of the good electronic conductivity and charge transfer kinetics. A maximum output power density of 1260.54 mW cm−2 at 900 mA cm−2 is also possible. Furthermore, the electrochemical mechanism of the AgO electrode is further uncovered by Ex-situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and transmission electron microscope (TEM) studies. Thus, this research presents a viable possibility for the fabrication of aqueous AgO–Al batteries by demonstrating the use of high purity AgO as a cathode active material.

Engineering nanostructured Ag doped α-MnO2 electrocatalyst for highly efficient rechargeable zinc-air batteries

Engineering of highly active, and non-precious electrocatalysts are vital to enhance the air-electrodes of rechargeable zinc-air batteries (ZABs). We report a facile co-precipitation technique to develop Ag doped α-MnO2 nanoparticles (NPs) and investigate their application as cathode materials for ZABs. The electrochemical and physical characteristics of α-MnO2 and Ag doped α-MnO2 NPs were compared and examined via CP, CV, TGA/DTA, FT-IR, EIS, and XRD analysis. CV result displayed higher potential and current for ORR in Ag doped α-MnO2 NPs than α-MnO2; but, ORR performance decreased when the Ag doping was raised from 7.5 to10 mmol. Moreover, α-MnO2 and Ag doped α-MnO2 NPs showed 2.1 and 3.8 electron transfer pathway, respectively, showing Ag doped α-MnO2 performance to act as an active ORR electrocatalyst for ZABs. The EIS investigation exhibited that charge-transfer resistance for Ag doped α-MnO2 was extremely lower associated to the MnO2 demonstrating that the successful loading of Ag in α-MnO2. A homemade ZAB based on Ag–MnO2-7.5 showed a high open circuit potential, low ohmic resistances, and excellent discharge profile at a constant current density of 1 mA/g. Moreover, Ag–MnO2-7.5 show a specific capacity of 795 mA h g−1 with corresponding high energy density ∼875 Wh kg−1 at 1 mA cm−2 discharging conditions.

Integration of a steam accumulator with a biomass power-generation system for flexible energy storage and discharge: Effect of the initial steam pressure on the steam discharge profile and levelized cost of storage

Carnot batteries (pumped thermal energy-storage systems) are promising systems to reduce the cost of electricity storage and balance intermittent variable renewable energy. In this study, a steam accumulator (SA), which is a sensible heat-storage unit for the Carnot-battery system, was integrated with the existing steam Rankine cycle of a biomass power plant (2000 kWe, inlet steam temperature and pressure of 480 °C and 6.3 MPa, respectively). The surplus electric power of the renewable energy was converted into steam with electric heaters and stored in the SA as saturated steam. The dynamic profile of the steam discharge from the SA was modeled with Excel Visual Basic for Applications, and the energetic performance was calculated with Aspen Plus V12. The effect of the initial steam pressure in the SA (7.0–10.0 MPa) on the steam-discharge profile and levelized cost of storage (LCOS) was investigated for the case of a power increment of 500 kWe (25 %) and 4-h discharge per day. In addition, the influence of the capacity on the LCOS was investigated from 5 % to 30 %. The estimated required volume of the SA was 154.1 m3 (7.0 MPa) to 51.6 m3 (10.0 MPa). The capital cost for installing the SA system (the SA, electric heaters, superheaters, high-pressure pumps, and valves) was higher for lower initial steam pressure (0.586 MUSD for 7.0 MPa and 0.341 MUSD for 10.0 MPa) because a larger SA volume was required. The capital cost of the electric heaters was 0.294 MUSD irrespective of the initial steam pressure in the SA. The LCOS was 0.317 ± 0.035 to 0.347 ± 0.043 USD/kWhe at initial steam pressures of 10.0 to 7.0 MPa when the plant lifetime was 20 years. The sum of the capital and maintenance costs in the LCOS can be reduced to <0.10 USD/kWhe, excluding the cost of the charging electricity and labor cost. These results indicate that it is feasible and promising to integrate a SA system with an existing biomass power plant to add flexibility of power generation at relatively low cost, especially, in the case that the cost of surplus electricity is zero or negative.

A Novel Pentanary Metal Oxide Cathode with P2/O3 Biphasic Structure for High‐Performance Sodium‐Ion Batteries

AbstractThe rapid capacity loss suffered by P2‐type Mn‐based layered oxide cathode materials, caused by deleterious high‐voltage phase transformations and the dissolution of active materials, greatly limits their application in large‐scale sodium‐ion battery installations. In this study, a novel P2/O3 biphasic cathode is developed using a multi‐element (Fe, Mg, and Li) co‐substitution strategy. The results of ex situ X‐ray diffraction analyses and the absence of significant voltage plateaus in the charge–discharge profiles of cells featuring the proposed cathode indicate that deleterious phase transformations and concomitant lattice mismatch in the high‐voltage region are effectively suppressed because of the topotactic intergrown structure of the resulting cathode. The optimized cathode also demonstrates improved structural stability and enhanced Na+ diffusion kinetics, owing to the incorporation of stabilizing dopant pillars and suppressed metal‐ion dissolution. Hence, the resulting Na half cell demonstrates a high initial capacity of 170.5 mA h g−1 at 0.1 C and excellent rate capability (106.6 mA h g−1 at 10 C). Furthermore, the resulting Na full cell, featuring a hard carbon anode, displays excellent cycling stability (72.1% capacity retention after 400 cycles), demonstrating its practical viability. This study presents the design and optimization of high‐performance Mn‐based cathodes.

PH/redox-responsive core cross-linked based prodrug micelle for enhancing micellar stability and controlling delivery of chemo drugs: An effective combination drug delivery platform for cancer therapy.

Core-crosslinking of micelles (CCMs) appears to be a favorable strategy to enhance micellar stability and sustained release of the loaded drug. In this study, the DOX-conjugated pH-sensitive polymeric prodrug Methoxy Poly (ethylene oxide)-b-Poly (Aspartate-Hydrazide) (mPEG-P [Asp-(Hyd-DOX)] was created using ring-opening polymerization. To further enhance the micellar system, 3,3'-diselanediyldipropanoic acid (DSeDPA) was applied to link the hydrophobic segment via click reaction to form pH/redox-responsive CCMs. Dual anti-cancer drugs, DOX as a pro-drug and SN-38 as a targeting drug, were used to enhance inhibition. DLS confirmed that the non-cross-linked micelle (NCMs) showed a higher (96.43nm) particle size compared to the CCMs (72.63nm). Due to micellar shrinkage after crosslinking, CCMs displayed SN-38 drug loading (7.32%) and encapsulation efficiency (86.23%). The mPEG-P(Asp-Hyd) copolymer's in vitro cytotoxicity on HeLa and HaCaT cell lines found that 84.52% of the cells are alive, and zebrafish (Danio rerio) embryos and larvae are highly biocompatible. The DOX/SN-38@CCMs had a sustained discharge profile in vitro, unlike the DOX/SN-38@NCMs. In DOX/SN-38@CCMs, HeLa cells were inhibited 50.90% more than HaCaT (14.25%) at the maximum drug dose (10μg/mL). The CCMs successfully targeted and supplied DOX/SN-38 in HeLa cells rather than HaCaT cells, based on cellular uptake of 2D cell culture. CCMs, unlike NCMs, inhibit the growth of spheroids for extended periods of time due to the prolonged release of the loaded drug. Overall, CCMs are good-looking for use as regulated delivery of DOX/SN-38 in cancer cells because of all of these appealing characteristics.

Adaptation of river channels to a wetter or drier climate: Insights from the Lower Pilcomayo River, South America

Climate change has a direct influence on both hydrology and floodplain vegetation of water courses, which are key players in river morphodynamics. The river system response to climate change is complex and the effects of non-linear interactions between alterations in water, sediment and vegetation remain incompletely understood. Which of these components becomes dominant in shaping the river channel when climate becomes drier or wetter? To answer this question, we investigate the cross-sectional response of sand-bed rivers to climate change focusing on channel width and depth, which respond directly to changes in boundary stresses. Thanks to the exceptional availability of long time-series of daily discharge and cross-sectional profiles, the Pilcomayo River is an ideal living lab for this investigation. We constructed a two-dimensional model of the river using the open-source state-of-the-art, structured Delft3D code. The highly dynamic behaviour and quick morphological adaptation of the Pilcomayo allowed reducing the period of time covered by the simulations because the river cross-section adapts its morphology to a new value of the water discharge within hours or days, which is crucial for modelling investigations. Calibration and validation were successfully performed by comparison with historical data. We considered several scenarios representing current, dryer and wetter climates. The results show that a dryer climate reduces the river channel depth and enlarges the width. A wetter climate increases the channel depth but produces negligible widening. Vegetation, sparser with a drier climate and denser with a wetter climate, is found to control the channel width. This analysis is unique and shows which alterations can be expected in alluvial sand-bed rivers with natural vegetated banks due to climate change.

Cover Feature: Investigation of the Effect of Temperature on Lithium‐Sulfur Cell Cycle Life Performance Using System Identification and X‐Ray Tomography (Batteries &amp; Supercaps 8/2022)

The Cover Feature illustrates a discharge profile of a 19 Ah lithium-sulfur (Li-S) pouch cell subject to the required power on the Millbrook London Transport Bus (MLTB) driving cycle. In this study, cycle life performance of the Li-S cell is investigated at various temperatures using system identification and X-ray tomography methods. More information can be found in the Research Article by A. Fotouhi and co-workers.