Zinc Bromine Research Articles

Rechargeable aqueous zinc-bromine batteries: an overview and future perspectives.

Zinc-bromine batteries (ZBBs) receive wide attention in distributed energy storage because of the advantages of high theoretical energy density and low cost. However, their large-scale application is still confronted with some obstacles. Therefore, in-depth research and advancement on the structure, electrolyte, anode, cathode and membrane are of great significance and impendency. Herein, we review the past and present investigations on ZBBs, discuss the key problems and technical challenges, and propose perspectives for the future, with the focus on materials and chemistry. This perspective would provide valuable information on further development of ZBBs.

Scaling While Shorting: Lessons Learned When Non-Unity Coulombic Efficiency Is Independent of Cycle Life

The modern lithium ion battery has been engineered to impressive standards, with coulomibic efficiency approaching 99.999% and a safety record for well manufactured cells of less that on incident in 10,000,000 cell given the correct environmental and cycling standards. But the ion-shuttle mechanism within the the battery sets up the relationshipCremaining = Cinitial ηc cycles Over the past few years we have redesigned a zinc bromine battery that decouples this relationship almost completely, with the goal ofCremaining ≠ Cinitial ηc cycles In this approach we purposefully trade entropy management for cycle life, but it is not without its cost and challenges. In this presentation I will review the progress and challenges of a battery that does not fail critically under internal short circuit conditions, and discuss pathways and pitfalls we have discovered along the way.We will discuss: The extent to which side reactions can be "self-cancelling"The associated impact of heat generated by "guided" side reactionThe scaling behavior and functional and spatial heterogeneity encountered when one allows significant latitude in the reaction space within a cell.

A zinc bromine “supercapattery” system combining triple functions of capacitive, pseudocapacitive and battery-type charge storage

A dual-redox-additive-enhanced Zn–Br2 “supercapattery” is demonstrated with battery-level energy density and capacitor-level power density.

Modeling of Zinc Bromine redox flow battery with application to channel design

Here we present a 2-D combined mass transfer and electrochemical model of a zinc bromine redox flow battery (ZBFB). The model is successfully validated against experimental data. The model also includes a 3-D flow channel submodel, which is used to analyze the effects of flow conditions on battery performance. A comprehensive analysis of the effects of flow is included. We find that the zinc deposition decreases with flow distance during charging, and the opposite for the zinc de-plating process during discharging. The simulations also show that multiple curved flow channels can slightly improve the voltage efficiency of the ZBFB while the coulombic and energy efficiencies are slightly reduced. The model can be used for improving ZBFB design.

Techno-economic performance study of stand-alone wind/diesel/battery hybrid system with different battery technologies in the cold region of China

This paper analyzes the technical and economic feasibility of a hybrid wind/diesel/battery power system with different types of batteries for a small residential area encompassing 280 homes located in the suburbs of Lanzhou, Gansu province in China. The optimal allocation, economic, emissions, electricity output, and sensitivity analyses of the relevant hybrid systems are all analyzed by HOMER Pro software. Results indicate that the optimal hybrid energy system is the diesel generator (DG)/Zinc–Bromine (ZB) system, which contains a 1460 kW DG, 500 ZB flow batteries, and a 400 kW converter. This configuration corresponds to an initial capital of $1,170,200, an operating cost of $507,866/yr, a total net present cost (NPC) of $ 7,735,646, and a levelized cost of energy (COE) of $0.471/kWh. The DG/ZB system provides the lowest NPC and COE compared to a DG system, while the wind/lead-acid (LA) system has the highest NPC and COE owing to the high wind turbine costs. Furthermore, it is found that the DG/lithium-ion (LI) is the most environment friendly system compared to DG/ZB and DG/LA systems. It is also found that selecting the suitable wind turbine can improve the comprehensive performance of the hybrid power system in terms of technology, economy, and environment.

Activated Carbon‐Anchored 3D Carbon Network for Bromine Activity and its Enhanced Electrochemical Performance in Zn−Br2 Hybrid Redox Flow Battery

AbstractThere has been a huge demand on the usage of biomass‐derived activated carbon as an electrode and electrocatalyst for energy storage and conversion applications owing to its abundance, high surface area, good chemical stability, low cost, and eco‐friendliness. Herein, we report for the first time, activated carbon (AC) derived from Phyllanthus Emblica Leaves (PEL) (Indian gooseberry) biomass as an electrocatalyst for enhancing the bromine electro‐kinetics. The AC‐anchored graphite felt (AC−GF) showed excellent improvement in the bromine reversibility, which reinforces the overall performance of the zinc bromine redox flow battery (ZBRFB). Specifically, the AC−GF showed significant improvement in voltage efficiency. The flow cell employing AC in the positive electrode showed high Coulombic, voltage, and energy efficiency of 99, 83 and 82 %, respectively at a current density of 30 mA cm−2. Furthermore, the cell showed good cycle performance with 96.43 % Coulombic efficiency retention even after 100 cycles. Thus, the significant improvement in the cell performance unveils the good electrochemical/catalytic activity of the AC and therefore can be used as a potential low‐cost electrocatalyst in ZBRFB.

In Operando Visualization of the Electrochemical Formation of Liquid Polybromide Microdroplets

AbstractZinc–bromine flow batteries are promising for stationary energy storage, and bromine‐complexing agents have been used to form phase‐separated liquid polybromide products. However, an understanding of the dynamics of polybromide nucleation is limited due to the beam sensitivity and complexity of polybromides. Here we report an in operando platform composed of dark‐field light microscopy and a transparent electrochemical cell to reveal the dynamics of polybromide formation in their native environment. Using our platform, we confirm and reveal the liquid nature, chemical composition, pinning effect (strong interaction with Pt), residual effect (residual charge products on the surface), self‐discharging, and over‐oxidation of the polybromide products. The results provide insights into the role of complexing agents and guide the future design of zinc–bromine flow batteries. Furthermore, our in operando platform can potentially be used to study sensitive species and phases in other electrochemical reactions.

In Operando Visualization of the Electrochemical Formation of Liquid Polybromide Microdroplets.

Zinc-bromine flow batteries are promising for stationary energy storage, and bromine-complexing agents have been used to form phase-separated liquid polybromide products. However, an understanding of the dynamics of polybromide nucleation is limited due to the beam sensitivity and complexity of polybromides. Here we report an in operando platform composed of dark-field light microscopy and a transparent electrochemical cell to reveal the dynamics of polybromide formation in their native environment. Using our platform, we confirm and reveal the liquid nature, chemical composition, pinning effect (strong interaction with Pt), residual effect (residual charge products on the surface), self-discharging, and over-oxidation of the polybromide products. The results provide insights into the role of complexing agents and guide the future design of zinc-bromine flow batteries. Furthermore, our in operando platform can potentially be used to study sensitive species and phases in other electrochemical reactions.

Realizing highly efficient energy retention of Zn–Br2 redox flow battery using rGO supported 3D carbon network as a superior electrode

Zinc–Bromine redox flow battery (Zn–Br2 RFB) is one of the most promising aqueous metal hybrid flow batteries used to store high energy in mega scale. This aqueous system provides high cell voltage with high practical energy density over the other redox flow systems. Conversely, poor reversibility of bromide/bromine redox couple strictly affects cell performances such as rate capability, cell efficiency and cycle life. In the present work, the rate capability is enhanced to 80 mA cm−2 by improving the bromine reversibility in the positive electrode. First time, reduced Graphene Oxide (rGO) is employed to improve the bromine kinetics in the Zn–Br2 redox flow battery. The electrochemical analysis showed highly renovated bromine kinetics with less peak separation potential (103 mV) and very closer onset potentials (anodic reaction: 0.92 V & cathodic reaction: 1.08 V). Moreover, the obtained anodic (Ia) and cathodic (Ic) peak current ratio (Ia/Ic) 0.83 indicates the improved reversibility of bromine reactions on rGO supported 3D carbon felt electrodes. Importantly, the cell showed increased energy efficiency of 80.75% for the rGO supported electrode based flow system over the studied cycle range. Thus, the rGO based electrode materials have fascinated more interest as an efficient electrocatalyst for Zn–Br2 RFB development.

A feasibility study on integrating large-scale battery energy storage systems with combined cycle power generation – Setting the bottom line

Strong attention has been given to the costs and benefits of integrating battery energy storage systems (BESS) with intermittent renewable energy systems. What's neglected is the feasibility of integrating BESS into the existing fossil-dominated power generation system to achieve economic and environmental objectives. In response, a life cycle cost-benefit analysis method is introduced in this study taking into consideration three types of battery technologies, namely, vanadium redox flow battery, zinc bromine flow battery, and lithium-iron-phosphate battery. The objective is to evaluate the life cycle carbon emissions and cost of electricity production by combined cycle power generation with grid-connected BESS. Findings from the Singapore case study suggest a potential 3–5% reduction in the life cycle carbon emission factors which could translate to a cumulative carbon emission reduction of 9–16 million tonnes from 2018 to 2030 from electricity generation. Grid-connected BESS could reduce the levelized cost of electricity by 4–7%. A synergistic planning of CCGT and BESS could theoretically reduce the system level power generation capacity by 26% albeit a potential increase in the overall capital cost at the current cost of batteries. The projected battery cost reduction is critical in improving the feasibility of large-scale deployment.

(Invited) Zinc Based Flow Battery for Stationary Energy Storage

Key words: flow battery, zinc based, energy storage, prospects and challenges Zn2+/Zn redox couple attracts more and more attention in flow battery due to its characteristics of high solubility, low cost electrochemical reversibility and environmental friendly. Until now, many zinc based flow battery systems such as zinc-bromine1, zinc- nickle and zinc-iron2,3 etc. have been investigated, which have very promising prospect for stationary energy storage. Among them, zinc-bromine is one of the most successfully example of zinc based flow battery system, while zinc nickle and zinc iron systems have obtained tremendous developments recently. At the same time, many new zinc based systems such as zinc iodine have been proposed and demonstrated great advantages in some aspects such as energy density. However, secondary batteries that use zinc electrodes typically exhibit short lifetimes, because of problems with undesirable zinc morphology especially zinc dendrites, that form during charge. Hence, the challenge is to deposit a compact, uniform and free of dendrite layer that ensure a long cycle secondary negative electrode. In recent years, DICP devoted to Zinc based batteries and implemented several demonstrations on zinc bromine flow batteries in different fields. Therefore, in this presentation we will introduce the research and development status of zinc based flow batteries at DICP.

A Review of Battery Energy Storage Systems for Residential DC Microgrids and Their Economical Comparisons

In residential DC microgrids integrated with renewable energy sources (RESs), prosumer’s power generation and load demand are not matched due to inherent sporadic nature of RESs. One way to address this issue is to add an energy storage system (ESS). The ESS is useful in fluctuation suppression, load following, time shifting, peak shaving, energy saving and emergency power. Moreover, an ESS will resolve overvoltage issue in utility grids due to exported surplus energy from residential RESs. Therefore, this paper will review battery ESSs that can be used in residential DC microgrids. Three major battery chemistries, i.e. leadacid, lithium ion (Li-ion) and Zinc bromine (ZB) are reviewed. The analysis of the levelized cost of energy reveals that lead-acid batteries are economically less competitive compared with Li-ion and ZB batteries in residential DC microgrid applications.

Metal Oxide Coatings on Carbon Electrodes with Large Mesopores for Deeply Charged Zinc Bromine Redox Flow Batteries

Carbon nanofibers with various large mesopores (>10nm) were made and tested as active cathode materials for zinc bromine redox flow batteries. The largest mesopores demonstrated improvements over activated carbon in coulombic efficiency as well as rate capability up to 30mA/cm2. Afterwards, the mesoporous carbon nanofibers were coated with four amorphous metal oxides made from liquid precursors to form a protective coating, and their protective nature was examined through deep and shallow charge cycles. The effect of the coating on battery performance was then analyzed through galvanostatic testing, cyclic voltammetry, and electrochemical impedance spectroscopy. It was determined that the metal oxide coatings improved rate capability and voltaic efficiency by adsorbing the bromine complex more readily, while the large mesopores aided performance from a combination of absorption and more efficient diffusion.

Pyrolytic carbon felt electrode Inhibits Formation of Zinc Dendrites in Zinc Bromine Flow Batteries

Pyrolytic carbon felt electrode Inhibits Formation of Zinc Dendrites in Zinc Bromine Flow Batteries

Increased Benefit Of ZnBr Flow Battery With 33kWp PV System And Smart Tariff Structure

With the rollout of proposed smart grid tariff structures in the Republic of Ireland the modelled role of an energy storage device in reducing the energy and economic loads of a public school building is presented. The school building has a 33kWp photovoltaic system, the performance of which is compared to other PV systems in the Irish environment. Concurrently, a Zinc Bromine flow battery has been operated under various charge and discharge rate cycles and the overall energy performance of this system has been virtually matched to the output of the PV. The scenarios trialled include ‘business as usual’ modelling the economic impact of smart grid tariffs versus a flat rate tariff as currently operation with PV in situ; a ‘peak shifting’ scenario where the battery operation is linked solely to the smart grid tariff rates and ignores PV resource and a ‘PV optimisation’ scenario where the PV output is considered ‘free’ energy and as such has priority in storage. The three scenarios show that the greatest economic impact comes from the ‘PV optimisation’ scenario, which is mainly related to PV generation at low economic value times.

Enhancement of Bromine Reversibility using Chemically Modified Electrodes and their Applications in Zinc Bromine Hybrid Redox Flow Batteries

AbstractOne of the significant issues that play a vital role in the determination of the performance of Zinc‐Bromine Redox Flow Battery system is the reversibility of bromine/bromide redox couple. In this work, surface modified carbon paper is used to improve the reversibility of bromine/bromide redox couple and successfully demonstrated in Zinc‐Bromine Redox Flow Battery as a positive electrode. It is evidenced that the flow cell fabricated using surface modified carbon paper showed better reaction kinetics than that of pristine carbon paper based flow cell. Further, the samples are subjected to various electrochemical and physical characterization techniques to evidence the improvement in the cell function. From the obtained cell characteristics, it is noted that the cell fabricated using surface modified carbon delivered better efficiency in terms of Coulombic (95 %), voltaic (86 %), and energy (78 %) at a current density of 20 mA/cm2. Thus, the improved effective reversibility of bromine/bromide redox couple of functionalized carbon electrode material can be a potential candidate for Zinc‐Bromine Redox Flow Battery applications.

Pathways Toward Enhanced Techno-Economic Performance of Flow Battery Systems in Energy System Applications

Redox flow batteries have shown great potential for a wide range of applications in future energy systems. However, the lack of a deep understanding of the key drivers of the techno-economic performance of different flow battery technologies—and how these can be improved—is a major barrier to wider adoption of these battery technologies. This study analyzes these drivers and provides an extensive comparison of four flow battery technologies, including the all-vanadium redox (VRB), iron–chromium, zinc–bromine, and polysulfide–bromine flow batteries, by examining their current and projected techno-economic performances. We address the potential for performance improvements and resulting cost reduction by developing a component-based learning curve model. The model considers the near-term learning rates for various subcomponents of each of the four battery technologies as well as their technological improvements. The results show that (i) both technological improvements in the performance parameters as well as mass production effects could drive significant cost reductions for flow battery systems; (ii) flow battery systems could be cost-effective in a variety of energy system applications in the near future; and (iii) from a techno-economic perspective, VRB systems are more suitable for the applications that require low energy and high power capacities.

The Research Progress Of Zinc Bromine Flow Battery

Zinc bromine redox flow battery (ZBFB) has been paid attention since it has been considered as an important part of new energy storage technology. This paper introduces the working principle and main components of zinc bromine flow battery, makes analysis on their technical features and the development process of zinc bromine battery was reviewed, and emphasizes on the three main components of zinc bromine battery, and summarizes the materials and applications of electrolyte, membrane and electrode. At the same time, the solution to the technical problems of zinc bromine flow battery is also briefly analyzed. Finally, the future development of zinc bromine battery system is prospected.

Towards a uniform distribution of zinc in the negative electrode for zinc bromine flow batteries

Achieving a uniform distribution of zinc in the negative electrode is crucial to increase the electrode utilization, maximize the discharge capacity, suppress the dendrite formation and enhance the cycling stability for zinc bromine flow batteries (ZBFBs). To promote the uniform distribution of zinc and thus propel the commercial applications for ZBFBs, in this work, a first-principles study is carried out to investigate the zinc adsorption and diffusion on representative carbon surfaces, including a pristine graphite (0 0 0 1) surface, two surfaces with vacancies, and three surfaces with oxygen-functional groups, aiming to unravel the effect of carbon defects on the ion transport inside the porous electrode, clarify the underlying zinc anchoring mechanism and seek effective ways to promote the uniform distribution of zinc. It is found that the zinc distribution and morphology can be varied by adjusting carbon surface properties, especially by increasing the number of single vacancy. A graphite felt negative electrode with a high content of carbon defects is then prepared and tested in ZBFBs. Experimental results reveal that a much more uniform distribution of zinc is achieved in the prepared electrode than the original electrode does after charing, demonstrating the validity of our proposed mechanism and method. The results reported here provide new insights and novel methods to fabricate uniformly distributed zinc negative electrode, which can guide the rational design of electrode and promote the future applications of ZBFBs and other hybrid flow batteries (e.g. Zn-I2, Zn-Ce and all-iron).

A Zinc–Bromine Flow Battery with Improved Design of Cell Structure and Electrodes

AbstractThe zinc–bromine flow battery (ZBFB) is regarded as one of the most promising candidates for large‐scale energy storage owing to its high energy density and low cost. However, because of the large internal resistance and poor electrocatalytic activity of graphite‐ or carbon‐felt electrodes, conventional ZBFBs usually can only be operated at a relatively low current density, which limits their widespread application. Herein, we propose an asymmetrical cell by replacing the conventional thick felt electrode with a thin and electrocatalytically active carbon‐paper (CP) electrode interfacing with a flow‐field structure. With the enhanced electrocatalytic activity of CP for the Br2/Br− redox reaction and the reduced internal resistance of the thinner electrode, the ZBFB with this newly proposed structure exhibits an energy efficiency of up to 83.5 % at a current density of 40 mA cm−2, much higher than that with a graphite‐felt electrode of only 73.0 %. Remarkably, the battery can even be operated at a high current density up to 100 mA cm−2 while maintaining an energy efficiency of more than 70 %, demonstrating an excellent rate capability.