Energy-storage Welding Connection Characteristics of Rapid Solidification AZ91D Mg Alloy Ribbons

Energy-storage welding connection characteristics of rapidly solidified AZ91D Mg alloy ribbons with 40-70 μm thickness are investigated using a microtype energy-storage welding machine. The microstructure and performance of the connection joints are analyzed and studied. The research results indicate that energy-storage welding is able to realize the spot welding connection of AZ9ID Mg alloy ribbons. The welding nugget consists of developed α-Mg equiaxed grains with the sizes of 1.2-2.7 μm and intergranular distributed β-Mg17Al12 compounds. The thickness of bond zone is about 4 μm and the solidification microstructure is characterized by the fine equiaxed grains with the sizes of 0.8-1.2μm and grain boundary has become coarsening. The columnar crystal in HAZ also becomes slightly coarsening and the grain boundary has broadened, however, there is no obvious change in its primitive morphology and crystallographic direction. When welding energy is about 2.0 J, the welding joints with higher shear strength and smaller electrical resistivity are obtained.

Energy-storage configuration for EV fast charging stations considering characteristics of charging load and wind-power fluctuation

Fast charging stations play an important role in the use of electric vehicles(EV)and significantly affect the distribution network owing to the fluctuation of their power.For exploiting the rapid adjustment feature of the energy-storage system(ESS),a configuration method of the ESS for EV fast charging stations is proposed in this paper,which considers the fluctuation of the wind power as well as the characteristics of the charging load.The configuration of the ESS can not only mitigate the effects of fast charging stations on the connected distribution network but also improve its economic efficiency.First,the scenario method is adopted to model the wind power in the distribution network,and according to the characteristics of the EV and the driving probability,the charging demand of each station is calculated.Then,considering factors such as the investment cost,maintenance cost,discharging benefit,and wind curtailment cost,the ESS configuration model of the distribution network is set up,which takes the optimal total costs of the ESS for EV fast charging stations within its lifecycle as an objective.Finally,General Algebraic Modelling System(GAMS)is used to linearize and solve the proposed model.A simulation on an improved IEEE-69 bus system verifies the feasibility and economic efficiency of the proposed model.

Li-ion Battery Failure Warning Methods for Energy-storage Systems

Energy-storage technologies based on lithium-ion batteries are advancing rapidly.However,the occurrence of thermal runaway in batteries under extreme operating conditions poses serious safety concerns and potentially leads to severe accidents.To address the detection and early warning of battery thermal runaway faults,this study conducted a comprehensive review of recent advances in lithium battery fault monitoring and early warning in energy-storage systems from various physical perspectives.The focus was electrical,thermal,acoustic,and mechanical aspects,which provide effective insights for energy-storage system safety enhancement.

Achieving high dielectric energy-storage properties through a phase coexistence design and viscous polymer process in BNT-based ceramics

In the last few decades,dielectric capacitors have gotten a lot of attention because they can store more power and charge and discharge very quickly.But it has a low energy-storage density(Wrec),efficiency(h),and temperature stability.By adding Pb(Mg1/3Nb2/3)O3(PMN)and(Bi0$1Sr0.85)TiO3(BST)to a nonstoichiometric(Bi0$51Na0.5)TiO3(BNT)matrix,the goal is to change the phase transition properties and make the material more relaxor ferroelectric(RFE)by lowering the remnant polarization Pr and keeping the maximum polarization Pmax.A viscous polymer process(VPP)is used to improve the electric breakdown strength,which is also a key part of being able to store energy.By working together,ceramics with the formula 0.79[0.85BNT-0.15PMN]-0.21BST(BP-0.21BST)are made.The phase structure has been changed from a rhombohedral phase to a rhombohedral-tetragonal coexisted phase.This is beneficial for RFE properties and gives a Wrec of 6.45 J/cm^(3) and a h of 90%at 400 kV/cm.Also,the energy-storage property is very temperature stable between 30 and 150C.These results show that process optimization and composition design can be used to improve the energy storage properties,and that the dielectric ceramic materials made can be used in high-powder pulse dielectric capacitors.

Achieving stable relaxor antiferroelectric P phase in NaNbO_(3)-based lead-free ceramics for energy-storage applications

Compared with antiferroelectric(AFE)orthothombic R phases,AFE orthothombic P phases in Na NbO_(3)(NN)ceramics have been rarely investigated,particularly in the field of energy-storage capadtors.The main bottlenedk is closely related to the contradiction between d fficultly achieved stable relaxor AFE P phase and easily induced P-R phase transition during modifying dhemical compositions.Herein,we reporta novel lead-free AFE ceramic of(1-x)NN-x(Bi_(0.5)K_(0.5))ZrO_(3)((1-x)NN-xBKZ)with a pure AFE P phase str ucture,which exhibits excellent energy-storage characteristics,such as an ultrahigh recoverable energy density(W_(rec))-4.4 J/cm^(3) at x=0.11,a large powder density P_(D)-104 MW/cm^(3) and a fast discharge rate t_(0.9)-45 ns.The analysis of polarization-field response,Raman spectrum and transmission elecron microscopy demonstrates that the giant amplification of W_(rec) by≥177% should be ma inly ascribed to the simultaneously and effectively enhanced AFE P phase stbility and its relaxor dharacteristics,resulting in a diffused reversible electric field-induced AFE P-ferroelectric phase transition with concurrently incre.ased driving electric fields.Different from mast(1-x)NN-xABO_(3) systems,it was found that the reduced polarizability of B-site cations dominates the enhanced AFE P-phase stability in(1-x)NN-xBKZ ceramics,but the almost unchanged tolerance factor tends to ause the AFE R phase to be induced at a relatively high x value.

Ni, Co-double hydroxide wire structures with controllable voids for electrodes of energy-storage devices

We re port the facile synthesis of Ni,Co-double hydroxide wire(NCHW)-based electrodes directly grown on a conductive substrate via a hydrothermal process.Various NCHW nanostructures were grown on Ni foam,and the growth was controlled using different compositions of solvents(ethanol and water).With increasing volume ratio of ethanol to water,the density of the wires decreased,and the spatial voids between the wires increased.The formation of large empty spaces improved the electrochemical performance because the exposure of a large surface area of the structure to the electrolyte resulted in a large number of active sites and facile electrolyte penetration into the structure.The different NCHW structures were ascribed to the pivotal role of the solvent in the urea hydrolysis;the solvent triggered the formation of hydroxides during the hydrothermal synthesis.The electrochemical performance of the NCHW electrodes was investigated via galvanostatic charge/discha rge tests,cyclic voltammetry,and electrochemical impedance spectroscopy.The highest specific capacitance was 1694.7 m F/cm^2 at 2 mA/cm^2,with excellent capacitance retention of 81.5% after 5000 cycles.The superior electrochemical performance of the NCHW electrodes is attributed to the large number of active sites and facile electrolyte diffusion into the structure,due to the well-organized structure with an optimized density of nanowires and large voids between the wires.

Switching and energy-storage characteristics in PLZT 2/95/5 antiferroelectric ceramic system

Switching mechanisms and energy-storage properties have been investigated in(Pb_(0.98)La_(0.02)T(Zr_(0.95)Ti_(0.05)T_(0.995O_(3)) antiferroelectric ceramics.The electric field dependence of polarization(P–E hysteresis loops)indicates that both the ferroelectric(FE)and antiferroelectric(AFE)phases coexist,being the AFE more stable above 100℃.It has been observed that the temperature has an important influence on the switching parameters.On the other hand,the energy-storage density,which has been calculated from the P–E hysteresis loops,shows values higher than 1 J/cm^(3) for temperatures above 100℃ with around 73%of efficiency as average.These properties indicate that the studied ceramic system reveals as a promising AFE material for energy-storage devices application.

Techno-economic analysis of the Li-ion batteries and reversible fuel cells as energy-storage systems used in green and energy-efficient buildings

Green buildings have become broadly adopted in commercial and residential sectors with the objective of minimizing environmental impacts through reductions in energy usage and water usage and,to a lesser extent,minimizing environmental disturbances from the building site.In this paper,we develop and discuss a techno-economic model for a green commercial building that is 100%powered by a photovoltaic(PV)system in stand-alone configuration.A medium-sized office building in El Paso,TX was modelled to rely on a photovoltaic system to supply all of its electricity needs either directly from the PV system or through an energy-storage system(ESS)using Li-ion batteries(LIBs)or reversible fuel cells(RFCs).Cost results show that a 400-kW PV system can generate electricity at a cost of 2.21 cents/kWh in El Paso,TX and the average levelized cost of energy storage(LCOS)using 450-kW RFC is~31.3 cents/kWh,while this could reach as low as 25.5 cents/kWh using a small LIB ESS.While the RFC provides the flexibility required to meet building-energy demand,LIBs may not be able to meet building needs unless the storage size is increased substantially,which in turn incurs more energy-storage cost,making LIBs less favourable from an economic perspective.Sensitivity analysis revealed that capital cost,discount rate and expected system lifetime play key roles in shaping the LCOS in both systems.

Ordered Macroporous MoS_(2)-Carbon Composite with Fast and Robust Sodium Storage Properties to Solve the Issue of Kinetics Mismatch of Sodium-Ion Capacitors

Metal-ion capacitors(including Li^(+),Na^(+),and K^(+))effectively combine a battery negative electrode capable of reversibly intercalating metal cations,together with an electrical double-layer positive electrode.However,such novel cell design has a birth defect,namely kinetics mismatch between sluggish negative electrode and fast positive electrode,thus limiting the energy-power performance.Herein,we design a MoS_(2)-carbon composite anode with the ordered macroporous architecture and interlayer-expanded feature,exhibiting the fast and reversible Na^(+)redox processes.This kinetically favored anode is coupled with a homemade activated carbon cathode that allows for the excellent electrochemical performance of sodiumion capacitor with respect to large specific capacity,high-rate capability,and robust cycling.Through quantification of the potential swings of anode and cathode via a three-electrode Swagelok cell,we for the first time observe the abnormal variation law of potential swings and thus directly providing the evidence that the kinetics gap has been filled up by this kinetically favored anode.Our results represent a crucial step toward understanding the key issues of kinetics mismatch for hybrid cell,thus propelling the development of design of kinetically favored anode materials for high-performance metalion capacitors.

Non-aqueous lithium bromine battery of high energy density with carbon coated membrane

Flow batteries with high energy density and long cycle life have been pursued to advance the progress of energy storage and grid application. Non-aqueous batteries with wide voltage windows represent a promising technology without the limitation of water electrolysis, but they suffer from low electrolyte concentration and unsatisfactory battery performance. Here, a non-aqueous lithium bromine rechargeable battery is proposed, which is based on Br;/Br;and Li;/Li as active redox pairs, with fast redox kinetics and good stability. The Li/Br battery combines the advantages of high output voltage（;.1 V）,electrolyte concentration（3.0 mol/L）, maximum power density（29.1 m W/cm;） and practical energy density（232.6 Wh/kg）. Additionally, the battery displays a columbic efficiency（CE） of 90.0%, a voltage efficiency（VE） of 88.0% and an energy efficiency（EE） of 80.0% at 1.0 m A/cm;after continuously running for more than 1000 cycles, which is by far the longest cycle life reported for non-aqueous flow batteries.

Degradation of Aqueous 2,6-Dibromophenol Solution by In-Liquid Dielectric Barrier Microplasma

Degradation of 2,6-dibromophenol (2,6-DBP) in the aqueous solution was studied using dielectric barrier discharge in micro-bubbles. Experimental comparison of working gas Ar, N2, O2, and air showed that oxygen and air plasma efficiently decomposed 2,6-DBP to bromide ion, and inorganic carbon. The molecular orbital model was applied in the analysis of the degradation in electrophilic, nucleophilic, and radical reactions.

All Binder-Free Electrodes for High-Performance Wearable Aqueous Rechargeable Sodium-Ion Batteries

Extensive efforts have recently been devoted to the construction of aqueous rechargeable sodium-ion batteries(ARSIBs)for large-scale energy-storage applications due to their desired properties of abundant sodium resources and inherently safer aqueous electrolytes.However,it is still a significant challenge to develop highly flexible ARSIBs ascribing to the lack of flexible electrode materials.In this work,nanocube-like KNiFe(CN)6(KNHCF)and rugby balllike NaTi2(PO4)3(NTP)are grown on carbon nanotube fibers via simple and mild methods as the flexible binder-free cathode(KNHCF@CNTF)and anode(NTP@CNTF),respectively.Taking advantage of their high conductivity,fast charge transport paths,and large accessible surface area,the as-fabricated binder-free electrodes display admirable electrochemical performance.Inspired by the remarkable flexibility of the binder-free electrodes and the synergy of KNHCF@CNTF and NTP@CNTF,a high-performance quasi-solid-state fiber-shaped ARSIB(FARSIB)is successfully assembled for the first time.Significantly,the as-assembled FARSIB possesses a high capacity of 34.21 mAh cm?3 and impressive energy density of 39.32 mWh cm?3.More encouragingly,our FARSIB delivers superior mechanical flexibility with only 5.7%of initial capacity loss after bending at 90°for over 3000 cycles.Thus,this work opens up an avenue to design ultraflexible ARSIBs based on all binder-free electrodes for powering wearable and portable electronics.

Application of non-isolated bidirectional DC-DC converters for renewable and sustainable energy systems:a review

The primary challenge in renewable-energy utilization is an energy-storage system involving its power converter.The systems have to promise high efficiency,reliability and durability.Also,all of these can be realized at an economical cost.Buck and boost converters connected in parallel can convert power in both directions.It is the basic non-isolated bidirectional topology commonly used with energy-storage systems.The primary issue with the buck-boost non-isolated bidirectional converter is how to enhance its performance,so the modification involving this topology is still conducted.This paper examines 29 proposed converters from 30 research publications published in the last 10 years,the most recent of which focuses on modified non-isolated bidirectional converters based on the buck-boost topology.These are classified into eight modification schemes,which involve adding new components or circuits to the base topology.Each is evaluated against six parameters:the number of components,control complexity,power-rating applications,soft-switching ability,efficiency outcome and capacity to minimize losses.Moreover,each modified non-isolated bidirectional converter was compared from the renewable-energy-based power-generation-source perspective utilized.Based on these studies,researchers might think of ways to improve the buck-boost converter by changing it to make a new non-isolated bidirectional converter that can be used in systems that need it.

Facile autoreduction synthesis of core-shell Bi-Bi2O3/CNT with 3-dimensional neural network structure for high-rate performance supercapacitor

Core-shell Bi-Bi2 O3/CNT(carbon nanotube) with 3-dimensional neural network structure where Bi-Bi2O3 nanospheres act as cell bodies supported by a 3-dimensional network of CNTs acting as synapses is designed and prepared by simple solvothermal method and subsequent annealing autoreduction treatment,and this structure facilitates the efficient transport of electrons.It can provide two electron transfer paths due to the double contact of Bi2O3 shell with CNT and metal Bi core which enhances the efficiency of the electrochemical reaction.The Bi-Bi2 O3/CNT electrode shows a high gravimetric capacitance of 850 F g-1(1 A g-1),and the specific capacitance of Bi-Bi2O3/CNT can be still 714 F g-1 at 30 A g-1 indicating excellent rate performance.The asymmetric supercapacitor is assembled with Bi-Bi2 O3/CNT as the negative electrode and Ni(OH)2/CNT as the positive electrode,delivering a high energy density of 36.7 Wh kg-1 and a maximum power density of 8000 W kg-1.Therefore,the core-shell Bi-Bi2O3/CNT with 3-dimensional neural network structure as the negative electrode of supercapacitor shows great potential in the field of energy storage in the future.

室温还原二氧化氮新策略:Li-NO2电池（英文）

氮氧化物(NOx)的排放给生态环境和人类社会带来了严重危害.传统净化措施成本高,同时难以实现污染物的循环利用,如何实现经济高效的NOx处理已经成为极具挑战的课题.本研究成功构建了一种新型锂-二氧化氮(Li-NO2)电池,阐明了其充放电机制,实现了NO2在室温下的高效还原.该体系在50 mA g–1的电流密度下实际能量密度高达666 Wh kg–1,NO2还原的法拉第电化学效率达到67%,能够在实现NO2还原的同时高效输出电能.这种新型Li-NO2电池的构建不仅为NO2的治理和再利用提供了新的研究思路,同时为其他污染物气体的高效利用提出了普适性策略.

Enhanced energy storage properties and antiferroelectric stability of Mn-doped NaNbO_(3)-CaHfO_(3) lead-free ceramics:Regulating phase structure and tolerance factor

NaNbO_(3)-based ceramics usually show ferroelectric-like P-E loops at room temperature due to the irreversible transformation of the antiferroelectric orthorhombic phase to ferroelectric orthorhombic phase,which is not conducive to energy storage applications.Our previous work found that incorporating CaHfO_(3) into NaNbO_(3) can stabilize its antiferroelectric phase by reducing the tolerance factor(t),as indicated by the appearance of characteristic double P-E loops.Furthermore,a small amount of MnO_(2) addition effectively regulate the phase structure and tolerance factor of 0.94NaNbO_(3)-0.06CaHfO_(3)(0.94NN-0.06CH),which can further improve the stability of antiferroelectricity.The XRD and XPS results reveal that the Mn ions preferentially replace A-sites and then B-sites as increasing MnO_(2).The antiferroelectric orthorhombic phase first increases and then decreases,while the t shows the reversed trend,thus an enhanced antiferroelectricity and the energy storage density Wrec of 1.69 J/cm^(3) at 240 kV/cm are obtained for 0.94NN-0.06CH-0.5%MnO_(2)(in mass fraction).With the increase of Mn content to 1.0%from 0.5%,the efficiency increases to 81% from 45%,although the energy storage density decreases to 1.31 J/cm^(3) due to both increased tolerance factor and non-polar phase.