Electrical Energy Storage Applications Research Articles

Investigating structural, dielectric and energy storage properties of NaNbO3 based ferroelectric ceramics

Sodium niobate (NaNbO3) based dielectric materials are getting recognition for the electric energy storage applications due to their promising ferroelectric/anti-ferroelectric properties. In the present work, (0.95-x)NaNbO3-0.05SrTiO3-xBi(Fe1/3Zn1/3Ti1/3)O3 (abbreviated as NNSTBFZT, x=0.04, 0.07 and 0.10) lead-free ferroelectric ceramics were synthesized using conventional solid-state reaction technique. A magnificent recoverable energy storage density (Wrec) and an ultrahigh energy storage efficiency (η) have been observed for x4 (∼1.05 J/cm3) and x10 (∼85 %) samples, respectively which reliant on the non-equivalent replacement of ions at the A and B sites of perovskite unit cell. Further, the phase investigation has been studied using X ray diffraction and Raman spectroscopy, which elucidate the effect of incorporation of the substituent ions at host matrix properly. A moderate dielectric constant with ultralow losses has been obtained and all the samples show diffuse phase transition, which is in favor of enhanced energy storage parameters. Moreover, the morphological analysis indicates decrease in grain size ∼ 1 µm, which also reflects the increased breakdown strength responsible for enhancing energy storage capacity. Therefore, proposed sodium niobate based ceramics become favorable for high energy dielectric capacitors applications.

Supercapacitors and rechargeable batteries, a tale of two technologies: Past, present and beyond

Supercapacitors and rechargeable batteries are energy storage devices where the performance strengths of one are traditionally the weaknesses of the other. Batteries benefit from superior energy storage capacity while supercapacitors possess higher power rates and longer cycle life. The rapid adoption of these devices in electric vehicles and grid energy storage applications is driving their further development and production. Accumulating and comprehending the current knowledge of both device technologies shall serve as a foundation for the progress in future research and development within these two distinct fields that share common goals. Therefore, in this review, we aggregate the supercapacitor and battery energy-power performance trends from over the last 18 years, to construct a projection of where the technologies could be heading in the coming decade. We specifically discuss the influence of each of these technologies in the energy storage landscape and their effect on hybridization research. Projections of the trends suggest that by 2040 the best-performing asymmetric and hybrid supercapacitors could be comparable to commercial battery technologies that are currently under development, in terms of energy density (ED). In terms of power density (PD), battery technology can achieve performance comparable to certain electrical double layer (EDL)-based supercapacitors. For some applications, we foresee that the two devices will continue to hybridize to fill the energy-power gap in a way that the penalty to PD for enhanced ED becomes insignificant. This expected improvement may eventually reach a saturation point, suggesting that once a certain level of ED is achieved, any further enhancements of the metric only lead to severe trade-offs with PD, and vice versa. The saturation observed in these technologies has also prompted an exploration of new pathways, with a notable emphasis on sustainability, to achieve high performance using renewable materials and methods.

High performance phenothiazine-based battery materials achieved by synergistic steric blocking and extended conjugation

Phenothiazine derivatives, as sustainable cathode materials for batteries, show significant promise for large-scale electrical energy storage applications. However, the irreversibility of the sulfur redox active center severely limits their energy density and discharge voltage in rechargeable organic batteries. This study concentrates on identifying the potential side reactions that contribute to the irreversibility of phenothiazine-based materials. We propose a molecular design strategy that synergistically blocks the active site and extends the conjugation, markedly improving the electrochemical reversibility of these materials. Our findings reveal that phenothiazine derivatives can undergo two successive, one-electron redox reactions without interference from chemical bond rearrangement and reactive radicals. The assembled cells, utilizing lithium (Li) and sodium (Na) as anodes, display two distinct discharge plateaus at 3.3/3.9 V vs. Li+/Li and 3.1/3.7 V vs. Na+/Na, respectively, with nearly identical contributions from the nitrogen (N) and sulfur (S) redox centers. The phenothiazine derivatives designed via this strategy rank among the few phenothiazine-based organic electrode materials capable of achieving highly reversible, two-electron transfer redox reactions in organic batteries.

Design and Implement a BTMS using Phase Change Material - A Review

Abstract: This paper presents a comprehensive review of the design and implementation of Battery Thermal Management Systems (BTMS) utilizing Phase Change Materials (PCM). The thermal management of batteries is crucial for ensuring optimal performance, safety, and longevity, particularly in electric vehicles and renewable energy storage applications. Phase change materials offer unique advantages for thermal management, including high latent heat storage capacity, thermal conductivity, and temperature regulation capabilities. This review discusses the fundamentals of PCM-based BTMS design, including PCM selection, integration methods, and system optimization techniques. Additionally, recent advancements, challenges, and future directions in PCM-based BTMS are explored, providing valuable insights for researchers, engineers, and industry practitioners in the field of energy storage systems.

Numerical study on thermal runaway in a cell and battery pack at critical heating conditions with variation in heating powers

The thermal stability of lithium-ion cell is still a major concern in electric vehicle and energy storage applications affecting the cell to its chemistry level. The thermal abuse is the most common type of thermal runaway which is triggered either by excess heat accumulation or localized heating in the battery pack. Analysis of thermal runaway in the perspective of various critical heating positions with temperature distribution, heat generation still lacks. Thus, the present work is focused on this issue. A three-dimensional homogeneous Multi-Scale, Multi-Dimensional model with a finite volume method solver ANSYS FLUENT has been utilised to assess the effect of heating positions, and variation in spacings on thermal runaway for a 18650 cell and battery pack in a detailed way. It is observed that the direction of flow is the typical deciding factor of the thermal runaway spreading pattern in the cell. The negative solvent is responsible for the generation of maximum heat in the thermal runaway of a 18650 cell. The results show that cell heated at the bottom end (10 mm width) is fast prone to thermal runaway, vertical (5 mm width) being slower in disturbing the separator stability. The NCA cathode material has a safety hierarchy that goes as follows with regard to positions: vertical 10 mm > bottom end > bottom 5 mm > centre 10 mm > bottom 10 mm. The effect of spacing on thermal runaway is varying non-uniformly with the location of the heating position in the 3 × 3 battery pack. The highest temperature attained by the 7000 W/m2 heating power battery pack is discovered to be greater than the 10,000 W/m2 by 10 K. With a power increase from 7000 W/m2 to 10,000 W/m2, there is a reduction in time delay of 17 %.

Probing Degradation in Lithium Ion Batteries with On-Chip Electrochemistry Mass Spectrometry.

The rapid uptake of lithium ion batteries (LIBs) for large scale electric vehicle and energy storage applications requires a deeper understanding of the degradation mechanisms. Capacity fade is due to the complex interplay between phase transitions, electrolyte decomposition and transition metal dissolution; many of these poorly understood parasitic reactions evolve gases as a side product. Here we present an on-chip electrochemistry mass spectrometry method that enables ultra-sensitive, fully quantified and time resolved detection of volatile species evolving from an operating LIB. The technique's electrochemical performance and mass transport is described by a finite element model and then experimentally used to demonstrate the variety of new insights into LIB performance. We show the versatility of the technique, including (a) observation of oxygen evolving from a LiNiMnCoO2 cathode and (b) the solid electrolyte interphase formation reaction on graphite in a variety of electrolytes, enabling the deconvolution of lithium inventory loss (c) the first direct evidence, by virtue of the improved time resolution of our technique, that carbon dioxide reduction to ethylene takes place in a lithium ion battery. The emerging insight will guide and validate battery lifetime models, as well as inform the design of longer lasting batteries.

Probing Degradation in Lithium Ion Batteries with On‐Chip Electrochemistry Mass Spectrometry**

AbstractThe rapid uptake of lithium ion batteries (LIBs) for large scale electric vehicle and energy storage applications requires a deeper understanding of the degradation mechanisms. Capacity fade is due to the complex interplay between phase transitions, electrolyte decomposition and transition metal dissolution; many of these poorly understood parasitic reactions evolve gases as a side product. Here we present an on‐chip electrochemistry mass spectrometry method that enables ultra‐sensitive, fully quantified and time resolved detection of volatile species evolving from an operating LIB. The technique's electrochemical performance and mass transport is described by a finite element model and then experimentally used to demonstrate the variety of new insights into LIB performance. We show the versatility of the technique, including (a) observation of oxygen evolving from a LiNiMnCoO2 cathode and (b) the solid electrolyte interphase formation reaction on graphite in a variety of electrolytes, enabling the deconvolution of lithium inventory loss (c) the first direct evidence, by virtue of the improved time resolution of our technique, that carbon dioxide reduction to ethylene takes place in a lithium ion battery. The emerging insight will guide and validate battery lifetime models, as well as inform the design of longer lasting batteries.

The Nanostructured Future of Electrolytes

Lithium-ion and lithium-metal batteries with cobalt-free high-energy cathodes, as well as the newly emerging batteries employing post-lithium ions as charge carriers, are a few topics tackled in recent years for the development of batteries with higher energy density, lower cost, and improved sustainability. While all of them could (and will) be improved over time, electrolytes are prominent because of their ease of adapting to current technologies. Conventional organic electrolytes are usually flammable, toxic, and harmful to humans and the environment. For these reasons, over the years, several alternatives have been proposed. Ionic Liquids1 are promising from a safety point of view, being non-volatile and non-flammable, but they are usually fluorinated to meet specific performance standards. Another sustainable and cost-efficient approach is represented by the Water-in-salt electrolytes (WiSEs)2,3, given that the used salt is sustainable itself. Finally, the newest approach is to tackle the solubility properties of salts to obtain locally concentrated electrolytes using non-solvating solvents4. For all of the proposed new technologies, their impressive properties seem to emerge from the peculiar structural organizations of the species in the system. Therefore, employing experimental (SAXS and Raman) and computational (MD and DFT) techniques to comprehensively understand how the chemical species interact in such systems, is mandatory to further progress in the research.Figure 1: a) Snapshot of the simulation box of a Locally Concentrated electrolyte. The ionic liquid comprise the worm-like structures, the solvent is only depicted on the left side as a transparent medium. b) coordination numbers as a function of salt concentration in a Water-in-salt electrolyte. c) X-ray scattering patterns for ionic liquid electrolytes and locally concentrated ionic liquid electrolytes at two different temperatures (20 °C top, and -20 °C bottom).References1 J. S. Wilkes, A short history of ionic liquids—from molten salts to neoteric solvents, Green Chemistry, 2002, 4, 73–80.2 L. Suo, F. Han, X. Fan, H. Liu, K. Xu and C. Wang, ‘water-in-Salt’ electrolytes enable green and safe Li-ion batteries for large scale electric energy storage applications, J Mater Chem A Mater, 2016, 4, 6639–6644.3 J. Han, A. Mariani, S. Passerini and A. Varzi, Energy Environ Sci, 2023, https://doi.org/10.1039/D2EE03682G4 X. Liu, A. Mariani, H. Adenusi and S. Passerini, Angewandte Chemie - International Edition, 2023,https://doi.org/10.1002/ange.202219318. Figure 1

Insights into P-Type Iron- and Manganese-Based Layered Sodium Cathodes

Sodium-ion batteries are a low-cost alternative to lithium-ion batteries in large-scale electric energy storage applications due to the natural-abundant sodium resources and similar working principle to LIBs during cycling [1]. Until now, many different cathodes for SIBs have been studied, including layered transition metal oxides (NaxTMO2, x<1), Prussian blue-type compounds, polyanionic and organic compounds [2]. Among them, NaxTMO2 has been extensively reported, due to its layered structure, easy synthesis, promising electrochemical properties, and feasibility for commercial production [3]. According to the occupation of Na ions and oxygen stacking, NaxTMO2 can be classified into P2 and O3 types, where P2 structure contasins trigonal prismatic sites of sodium ions and ABBA oxygen stacking sequence and O3 structure represents octahedral sites of sodium ions and ABCABC oxygen stacking sequence [4]. At low potentials (<2.0V), there is a phase transition P2-P2’ connected with the manganese redox activity and the Jahn-Teller distortion [5]. Compared with O3-type structure, P2-type NaxTMO2 provides higher specific capacity and better structural stability due to the lower diffusion barriers through Na-ion prismatic sites [6].Iron- and manganese-based layered oxides for sodium-ion batteries have attracted renewed interest due to their low cost and environmental friendliness. However, the phase change at high voltage and the Jahn-Teller effect lead to shortening cycle life and poor rate capability. We design a structure optimization of the Na2/3Mn1/2Fe1/2O2 cathode through a partial substitution of Fe3+ to explore the mechanism of redox activity of P2-type Mn/Fe-based layered cathodes. We present the investigation of the effect of simultaneous cationic substitution on the electrochemical performance and structural stability of P2-Na2/3Mn1/2Fe1/2O2. The obtained material exhibits a solid solution mechanism during desodiation/resodiation process and delivers an initial discharge capacity of 168 mA h g-1 at 0.1C and a capacity retention of 80% after 50 cycles. The modified P2 composition has stable cycle performance in the potential window from 1.5V to 4.5V. The main focus here is to understand the fundamental electrochemical mechanism of this layered cathode material by exploring the redox processes of transition metal cations and oxygen anions upon cycling. In situ X-ray synchrotron radiation diffraction is used to explore the structural changes during cycling. In situ X-ray Absorption Near Edge Spectroscopy is used to elucidate the local electronic structure of Fe and Mn atoms as it evolves throughout this electrochemical process. 23Na solid-state nuclear magnetic resonance spectroscopy is used to investigate Na coordination environments during desodiation/resodiation. Ex situ soft X-ray absorption spectroscopy results reveal the participation of oxygen anions in the electrochemical reactions. Thus, we explore the redox reactions of transition metals and oxygen to explain the mechanism and the electrochemical performance for the P2-type Mn/Fe-based layered cathodes.

Shunt Current Analysis of Vanadium Redox Flow Battery System with Multi-Stack Connections

Vanadium redox flow battery (VRFB) systems with multiple stacks due to long lifetime, low self-discharge, and flexible design, are commonly used in large-scale electrical energy storage applications In a VRFB system, pumps deliver positive and negative electrolytes to each stack through a piping system including channels and manifolds. However, the electrolyte flowing between cells through channels and manifolds and the electrolyte flowing between stacks through pipes are electrically conductive. Shunt currents are generated due to the voltage difference between the cells and between the stacks, which reduce the energy efficiency of the battery system. In particular, under different load connections, the shunt currents of a multi-stack VRFB system have different distributions and cause different impairments to the system efficiency. Therefore, it is important to predict the shunt currents of the multi-stack system under different load connections before the actual construction of the system. In this paper, a multi-stack VRFB system with 120 cells was explored by circuit-based modeling to evaluate the shunt currents according to the stack configuration such as serial, parallel, and mixed connections.Then, the Coulomb efficiencies (CEs) were investigated with operating currents at 36 and 54A. The results show that shunt currents are generally more significant at the center cell of a stack than at other cells under these stack configurations and exhibit a positive correlation with the battery state of charge (SOC), i.e., larger shunt currents increase with SOC. In addition, the CEs of the system are higher at 54A compared to those at 36A due to smaller shunt current losses regardless of the stack configurations. Furthermore, regardless of the operating current levels, the multi-stack system connected by parallel loads achieves the highest CEs compared to the series and mixed connected systems due to the absence of shunt current losses in the piping system. Figure 1

Polymorphs of Nb2O5 Compound and Their Electrical Energy Storage Applications.

Niobium pentoxide (Nb2O5), as an important dielectric and semiconductor material, has numerous crystal polymorphs, higher chemical stability than water and oxygen, and a higher melt point than most metal oxides. Nb2O5 materials have been extensively studied in electrochemistry, lithium batteries, catalysts, ionic liquid gating, and microelectronics. Nb2O5 polymorphs provide a model system for studying structure-property relationships. For example, the T-Nb2O5 polymorph has two-dimensional layers with very low steric hindrance, allowing for rapid Li-ion migration. With the ever-increasing energy crisis, the excellent electrical properties of Nb2O5 polymorphs have made them a research hotspot for potential applications in lithium-ion batteries (LIBs) and supercapacitors (SCs). The basic properties, crystal structures, synthesis methods, and applications of Nb2O5 polymorphs are reviewed in this article. Future research directions related to this material are also briefly discussed.

(Digital Presentation) Data-Driven Prognosis of Lithium-Ion Batteries Thermal Runaway Early Warning and Detection

Li-ion batteries (LIBs) are becoming ubiquitous in portable, stationary, and electrical energy storage applications that power various devices, from cell phones to the zero-emission plane. Market research suggests the $26.9 billion-a-year (2018) worldwide LIB market could reach $107 billion-a-year by 2025. Taking electric vehicles (EVs) for example, according to the Electric Drive Transportation Association (EDTA), the number of EV sales in the United States market has increased from 345 vehicles in 2010 to 331,617 in 2019, with a total cumulative number of 1.44 million vehicles over the ten-year sales period. This trend has also been observed in the global market as EVs' sales reached 2.1 million worldwide in 2019, boosting the stock to 7.2 million. Although the COVID-19 pandemic dramatically affected the global EV market and prompted the market to plummet over the year 2020 relative to 2019. The global EVs stock projections are expected to increase from 7.2 million to 14 million in 2025 and 25 million in 2030, accounting for 10% of global passenger vehicle sales in 2025 and 28% in 2030. Despite rapidly skidding into the EV era - a technical fait accompli- significant obstacles to vehicle electrification and adoption, especially the safety of their batteries, continue to threaten that future. The risk of anomaly generation and evolution (e.g., thermal runaway and exploration) is currently a major safety concern and challenge in applications powered by LIBs.The traditional first-principle simulations and comprehensive experiments are time-consuming or less effective in detecting and predicting the above problems induced by a synergistic effect of multiple degradation mechanisms. The above challenge eventually necessitates predictive or prognostic capability for Prognostics and Health Monitoring (PHM) under a complexly hostile working environment.This proposal will break away from existing practices, and instead, for the first time, the proposed data-driven prognosis (DDP) requires the assumption of the existence of a conservation principle but does not require a priori knowledge of the key mechanisms and boundary conditions. Alternatively, the exact form of the conservation functional is only specified locally, in the neighborhood of each observation point (and is assumed to be piecewise quadratic in the current work), whereas its global form remains unknown. The conservation principle is then defined as the minimization of system curvature at each observation point. The DDP methodology is based on the local curvature of the mathematical manifold representing the Euler-Lagrange governing equation of a system. The curvature represents a derivative of the total energy with respect to sensed variables, and instability is anticipated whenever the curvature exceeds a critical threshold, denoted by the inverse of the local length-scale of the manifold (or its extrinsic curvature). The length-scale, in turn, is calculated by solving the first moment of the state-space description (conservation of linear momentum) based on two consecutive time instants of measurements. In another sense, the DDP technique can estimate a mass normalized Energy Exchange Amplitude (EEA) that also represents a scaled “entropy rise” of the system. After acquiring the input data from the literatures, they were fed into DDP in a continuous order separated by each time step. At each time step, two consecutive time instances were considered that are sufficient to make the prognostication. The results of the simulation using the DDP are shown below. First the progression of PDI which shows the percentage of points that have reached different path dependence index (PDI) markers as shown in Figure 1 (a). It signifies the instants when the battery shows local instabilities. As shown in the figure, battery starts to show local instability from time instant 20 and beyond, highlighting the instability's progression. The chain length (CL) values and residual curvature information were analyzed as well and shown in Figure 1 (b) along with other criterias. As illustrated in the Figure, at time instant 10, the system crosses the critical chain length threshold and intensifies around time instance 20. Furthermore, the residual curvature (RC) value exceeds the critical threshold at time instance 19 and 21. The moment when all three criterias were met, the battery is expected to fail which is time instance 21 as shown in the Figure. Figure 1

Laser welding defects detection in lithium-ion battery poles

Strong demand for electric vehicles and energy storage applications has led to a rapid expansion of the battery sector. Laser welding is widely used in lithium-ion batteries and manufacturing companies due to its high energy density and capability to join different materials. Welding quality plays a vital role in the durability and effectiveness of welding structures. Therefore, it is essential to monitor welding defects to ensure welds quality. Manual inspection, analysis and evaluation of welding defect images is difficult due to the non-uniformity in their shape, position, and size. Hence the use of deep learning techniques to identify welding defects is more accurate and reliable due to the adequate training data samples, which helps to identify welding defects with greater accuracy. In this study, we present a novel collection of 3,736 laser welding images which are labeled with eight classes. This dataset contains both normal and defective classes collected from a Dade Laser Chinese production line. Moreover, we introduce a modified loss function that integrates cross entropy and complement objective training. The EfficientNetB6 model is trained with the newly introduced loss function that performed efficiently and achieved a promising accuracy during the classification phase. The experimental results demonstrate the significance of the proposed loss function and the sufficiency of EfficientNetB6 model on the laser welding dataset. Compared to other models, EfficientNetB6 performs better.

Optimized oxygen deficient mesoporous barium doped cobalt oxide: A wonder material for green energy generation and storage

Electrochemical energy conversion and storage systems are presently playing a lead role in the global energy platform. This study reports the fabrication of a Hydroelectric Cell (HEC) via the synthesis of oxygen-deficient barium-doped Co3O4 multifunctional material using a solid-state method for green electrical energy generation and storage applications. Different analytical methods were used to characterize the material. The Transmission and Scanning Electron micrographs of pure Co3O4 and Ba- Co3O4 revealed that doping with Barium metal into Co3O4 causes a change in morphology from a spherical shape to a sheet-like structure. The UV–vis spectroscopy indicates that the doping enhanced the band gap of Co3O4 from 1.65 to 2.52 eV and Brunauer Emmett Teller's investigation shows an increase in specific surface area from 8 m2/g to 13 m2/g. Further, an increase in oxygen deficiency due to Ba doping was confirmed with Photoluminescence spectroscopy, Electron Paramagnetic Resonance, and X-ray photoelectron spectroscope. The short circuit current of barium-doped HEC increased by 13 folds as compared to the undoped cell from 1.7 mA/cm2 to 21.6 mA/cm2, and its peak power increased by 18 times from 12.5 W/m2 to 227 W/m2. The power obtained from Ba-doped HEC is higher than typical solar panels of the same area and HEC has an edge over solar cells that it needs no light to produce energy therefore it can be used in the dark also. The specific capacitance of pure Co3O4 was 282.01 F/g which increased to 451.83 F/g after Ba doping. Moreover, the charge–discharge stability studies have established that the Ba- Co3O4 has a remarkable specific capacitance retention capability of 95% even after 2000 continuous charge-discharge cycles. Since this process involves water splitting, therefore hydrogen gas is produced as a byproduct that can be used for further energy generation. Thus, this material has enormous potential for application in the field of electrical energy generation, storage, and hydrogen gas production.

Integrated MnO2/PEDOT composite on carbon cloth for advanced electrochemical energy storage asymmetric supercapacitors

Advanced flexible supercapacitors with high energy/power density are an imperative research objective. In this study, a dually activated carbon cloth is designed as the functional current collector for supercapacitors. An electrodeposition technique is used for engineering Manganese Dioxide (MnO2) nanoflakes and profiting from a Poly (3,4 ethylene dioxythiophene; PEDOT) shield layer, a Li+-based neutral electrolyte high-performance freestanding asymmetric supercapacitors is constructed. The activated carbon cloth (ACC) provides an efficient electron-carrying route and the hierarchical nanostructure of the ACC@MnO2@PEDOT electrode. The integrated ACC@MnO2@PEDOT electrode exhibited exceptional capacitance performance of 1882.5 mF cm−2 (current density 1 mA cm−2) in 1.5 M aqueous LiCl electrolyte benefiting from ACC scaffold, the pseudocapacitive activity of MnO2 and substantial conductivity of the PEDOT polymer. Fabricating the structured electrode into an asymmetric supercapacitor revealed an enhanced areal energy density and an areal power density. The fabricated device demonstrated a broad voltage window of 1.8 V and extraordinary cycling stability of 94.6% after 10000 charge-discharge cycles. The unique scaffold, conducting PEDOT polymer, and MnO2 nanoflakes synergistically improved the cyclic performance and rate proficiency of the electrode, resulting in a supercapacitor with bendable electrical energy storage applications.

Modeling Thermal Runaway of Lithium-Ion Batteries at Cell and Module Level Using Predictive Chemistry

&lt;div&gt;Thermal runaway of lithium (Li)-ion batteries is a serious concern for engineers developing battery packs for electric vehicles, energy storage, and various other applications due to the serious consequences associated with such an event. Understanding the causes of the onset and subsequent propagation of the thermal runaway phenomenon is an area of active research. It is well known that the thermal runaway phenomenon is triggered when the heat generation rate by chemical reactions within a cell exceeds the heat dissipation rate. Thermal runaway is usually initiated in one or a group of cells due to thermal, mechanical, and electrical abuse such as elevated temperature, crushing, nail penetration, or overcharging. The rate of propagation of thermal runaway to other cells in the battery pack depends on the pack design and thermal management system. Estimating the thermal runaway propagation rate is crucial for engineering safe battery packs and for developing safety testing protocols. Since experimentally evaluating different pack designs and thermal management strategies is both expensive and time consuming, physics-based models play a vital role in the engineering of safe battery packs. In this article, we present all the necessary background information needed for developing accurate thermal runaway models based on predictive chemistry. A framework that accommodates different types of chemical reactions that need to be modeled, such as solid electrolyte interphase (SEI) layer formation and decomposition, anode-solvent and cathode-solvent interactions, electrolyte decomposition, and separator melting, is developed. Additionally, the combustion of vent gas is also modeled. A validated chemistry model is used to develop a module-level model consisting of networks of pouch cells, flow, thermal, and control components, which is then used to study the thermal runaway propagation at different coolant flow rates.&lt;/div&gt;

Hybrid GO/TiO2 nanoparticles reinforced NaAlg/PVA blend: Nanocomposites for high‐performance energy storage devices

AbstractIn this study, novel flexible polymer nanocomposite films formed of polyvinyl alcohol (PVA), sodium alginate (NaAlg), titanium dioxide (TiO2) and graphene oxide (GO) as nanofiller are fabricated by using casting method. The PVA/NaAlg‐GO/TiO2 nanocomposite films are characterized using various techniques. The synergistic effects of GO/TiO2 on the electrical, dielectric properties, and the energy density efficiency of PVA/NaAlg blend have been investigated in the range of frequency from 10 Hz to 7 MHz. The XRD data showed that the intensity of the PVA/NaAlg‐GO/TiO2 nanocomposites films decrease with nanofiller concentration. The FTIR spectroscopy provides proof that the complex formed. The optical studies were carried out using UV–Vis. spectroscopy. The energy bandgap values of PVA/NaAlg‐GO/TiO2 nanocomposite films were calculated using Tauc's plot. It is shown that the host matrix's Eg value decreases from 4.97 to 4.29 eV for direct transitions and from 4.37 to 2.29 eV for indirect transitions. The electrical and dielectric parameters of the nanocomposites showed that the maximum electrical properties were observed for the composite with 8 wt% loading of GO/TiO2. The σdc increased from 2.45 × 10−9 to 5.02 × 10−7 S cm−1. In addition, frequency exponent S decreased from 0.82 to 0.54. These findings demonstrated that there are significant modifications in the fabricated samples, which open the road for utilizing the PVA/NaAlg‐GO/TiO2 nanocomposite as flexible films for solar cells and electrical energy storage applications.

Uniform Longitudinal Zinc Growth beyond Interface Guided by Anionic Covalent Organic Framework for Dendrite‐Free Aqueous Zinc Batteries

AbstractAqueous zinc (Zn) batteries hold considerable promise to address safety problems that frequently occur in electric vehicle cells or energy storage applications. However, Zn metal anode suffers seriously from dendrite, corrosion, and interface water decomposition in aqueous electrolytes, especially under large areal capacity or long charging duration. This is mainly because of the uneven longitudinal Zn growth induced by the anisotropic Zn2+ diffusion, which is usually neglected in a laboratory study with low areal capacity. Herein, we report an artificial interface of the anodic covalent organic framework (COF, which can be rapidly synthesized and facilely assembled with Zn anode in a large area) to guide the uniform longitudinal Zn growth for dendrite‐free Zn batteries. In‐situ optical microscope observes that compared with the bare Zn anode, COF interface can promote the formation of the smooth and dendrite‐free surface through spatial‐triggered uniform longitudinal Zn growth. Theoretical calculation uncovers that anodic COF with a negative charge at its N sites could attract Zn2+ to achieve uniform longitudinal Zn2+ diffusion. In addition, this COF interface with superior hydrophobicity could suppress water decomposition and Zn corrosion. Consequently, the COF‐functionalized Zn anode realizes a high coulombic efficiency under severe Zn plating/stripping conditions (10 mAh cm−2), contributing to a long Zn‐I2 full battery life of over 10000 cycles. This work highlights the high‐areal‐capacity Zn anode protection in external space beyond the interface.

PbZrO3‐Based Anti‐Ferroelectric Thin Films for High‐Performance Energy Storage: A Review

AbstractEnergy storage capacitors occupy a large proportion in the pulse power equipment, and they play an important role nowadays. In recent years, anti‐ferroelectric materials have attracted increasing attention of researchers due to their high energy storage density. Compared with the lead‐free anti‐ferroelectric materials, PbZrO3 (PZ)‐based anti‐ferroelectric films are defined as promising electrical energy storage devices for pulsed power systems due to their ultrahigh energy storage density. During the past decade, numerous studies have been reported to develop high‐performance PZ‐based anti‐ferroelectric thin films for electrical energy storage applications. This review focuses on the recent progress of PZ‐based anti‐ferroelectric films for energy storage, and provides various ways, such as element modification (replacing of one element in the ABO3 structure by another element), composite materials (adding secondary phase into PZ films to form composite films), and process improvement (such as the tuning of different bottom electrodes), to improve their energy storage density. Finally, the problems and future development directions of the PZ‐based films are raised.

A Boost-Inductorless Electrolytic-Capacitorless Single-Stage Bidirectional Isolated AC–DC Converter

With the development of wide-bandgap devices, bidirectional isolated ac–dc converter becomes an attractive solution to realize highly compact, highly efficient power conversion for electric vehicle (EV) chargers and energy storage applications. However, in the existing literature, regardless of two-stage or single-stage isolated ac–dc converters, the circulating current in boost inductors is inversely proportional to the inductance value, resulting in large volume and high loss of the converter. In this article, a boost-inductorless electrolytic-capacitorless single-stage bidirectional ac–dc converter with high-frequency isolation is proposed. With the introduction of a center-tapped transformer, the proposed converter can achieve nearly zero circulating current without any boost inductor, thus overcoming the drawbacks mentioned above. Equivalent circuit analysis is applied to illustrate the operation principle and advantages of the proposed topology. A detailed comparison between the proposed topology and the state-of-the-art is also provided. The experimental results obtained from a 3.6 kW, 140 kHz single-phase EV charger prototype are given as the proof-of-the-concept. It is demonstrated that the proposed converter prototype realizes a peak efficiency of 96.4% with only 38 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> H total inductance and 6.33 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> F total capacitance.