A Self-Mediating Redox Flow Battery: High-Capacity Polychalcogenide-Based Redox Flow Battery Mediated by Inherently Present Redox Shuttles

Zhou, Yucun; Cong, Guangtao; Chen, Hongning; Lai, Nien-Chu; Lu, Yi‐Chun

doi:10.1021/acsenergylett.0c00611

Cited by 23 publications

(18 citation statements)

References 48 publications

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“…A variant of the SMRT reaction is the “self‐mediated” reactions proposed by Lu and co‐workers, between soluble polychalcogenides and insoluble ones for redox flow Li‐chalcogen batteries. [ 34 ] The full self‐mediated reactions are completed via a combination of electrochemical, comproportionation and disproportionation reactions of the inherently present polychalcogenides in the system at different stages of charge/discharge. Such a self‐mediated flow battery demonstrated very high catholyte volumetric capacities of 1268 and 1096 Ah L −1 for Li–S and Li–Se, respectively.…”

Section: Rt‐based Energy Storagementioning

confidence: 99%

Redox Targeting of Energy Materials for Energy Storage and Conversion

et al. 2021

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The redox‐targeting (RT) process or redox‐mediated process, which provides great operation flexibility in circumventing the constraints intrinsically posed by the conventional electrochemical systems, is intriguing for various energy storage and conversion applications. Implementation of the RT reactions in redox‐flow cells, which involves a close‐loop electrochemical–chemical cycle between an electrolyte‐borne redox mediator and an energy storage or conversion material, not only boosts the energy density of flow battery system, but also offers a versatile research platform applied to a wide variety of chemistries for different applications. Here, the recent progress of RT‐based energy storage and conversion systems is summarized and great versatility of RT processes for various energy‐related applications is demonstrated, particularly for large‐scale energy storage, spatially decoupled water electrolysis, electrolytic N2 reduction, thermal‐to‐electrical conversion, spent battery material recycling, and more. The working principle, materials aspects, and factors dictating the operation are highlighted to reveal the critical roles of RT reactions for each application. In addition, the challenges lying ahead for deployment are stated and recommendations for addressing these constraints are provided. It is anticipated that the RT concept of energy materials will provide important implications and eventually offer a credible solution for advanced large‐scale energy storage and conversion.

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Section: Rt‐based Energy Storagementioning

confidence: 99%

Redox Targeting of Energy Materials for Energy Storage and Conversion

et al. 2021

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“…Future work on using intrinsically present RMs for redox-targeting RFBs will further improve the voltage efficiency and simplify the system operation. [98]…”

Section: Redox Targeting Airfbsmentioning

confidence: 99%

Material Design of Aqueous Redox Flow Batteries: Fundamental Challenges and Mitigation Strategies

2020

Advanced Materials

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157

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redox flow systems to date. [7] However, their high chemical cost (V 2 O 5 , $24 kg −1) and low energy density (E d < 50 Wh L −1 , normalized based on both side of the electrolytes, unless specified otherwise) limit their wide implementation for large-scale grid storage. To boost the energy density of RFBs, nonaqueous RFBs with a wider potential window were developed. However, nonaqueous RFBs face intrinsic challenges such as high cost, flammability, and low ionic conductivity of organic electrolytes. [8] Here, we review recent developments of advanced materials for electrolyte design in ARFBs. We further classified ARFBs based on the type of active material: inorganic ARFBs (i.e., AIRFBs, including vanadium-, zinc-, iron-, polysulfide-based, and two other emerging systems); and organic ARFBs (i.e., AORFBs, including viologen-, 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO)-, quinone-, and N-centered heteroaromatic-mole culebased systems). We first summarize the fundamental physicochemical properties of redox couples in each ARFB system and then discuss critical challenges and mitigation design strategies to shed light on the design guidelines for future RFBs. Finally, assessment methodologies and metrics for evaluating battery stability among different ARFBs are discussed. 2. Aqueous Inorganic Redox Flow Batteries (AIRFBs) 2.1. Vanadium-Based AIRFBs 2.1.1. Fundamental Physicochemical Properties All-vanadium redox flow batteries (VRFBs, Figure 1a) are the most developed and widely used RFB system to date. Applying a vanadium element with diverse valence states (i.e., +2, +3, +4, and +5) effectively minimizes cross contamination, facilitates electrolyte regeneration, and provides long-term durability (Figure 1b-e). For example, a 200 MW/800 MWh system has been under construction by Dalian Rongke Power since 2016. [9] The reversible cell voltage of a VRFB is 1.26 V. The nominal cell voltage of VRFBs ranges from 1.15 to 1.55 V in acidic electrolytes, since the catholyte potential is pH-dependent. [10] The redox reactions on both sides are shown in the cyclic voltammetry (CV) analysis in Figure 1f. [11] Redox flow batteries (RFBs) are critical enablers for next-generation grid-scale energy-storage systems, due to their scalability and flexibility in decoupling power and energy. Aqueous RFBs (ARFBs) using nonflammable electrolytes are intrinsically safe. However, their development has been limited by their low energy density and high cost. Developing ARFBs with higher energy density, lower cost, and longer lifespan than the current standard is of significant interest to academic and industrial research communities. Here, a critical review of the latest progress on advanced electrolyte material designs of ARFBs is presented, including a fundamental overview of their physicochemical properties, major challenges, and design strategies. Assessment methodologies and metrics for the evaluation of RFB stability are discussed. Finally, future directions for material design to realize practical applications and achieve the comme...

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“…The redox flow batteries (RFBs) are a promising energy storage technology owing to the decoupled power and energy, high scalability, and high safety compared to commercial Li-ion batteries [1][2][3][4][5][6][7][8]. Recently, sulfur-containing materials receive remarkable attention in both aqueous [9][10][11][12][13] and nonaqueous flow systems [14][15][16][17][18][19][20][21] owing to their low cost and high solubility compared with vanadium-based flow battery [22][23][24][25]. However, polysulfides suffer from severe crossover [7,10,12], which results in low coulombic efficiency and limited lifespan.…”

Section: Introductionmentioning

confidence: 99%

A Low-Crossover and Fast-Kinetics Thiolate Negolyte for Aqueous Redox Flow Batteries

Yang

Wang

et al. 2022

Energy Mater Adv

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Aqueous redox flow batteries (ARFBs) are a promising technology for large-scale energy storage. Developing high-capacity and long-cycle negolyte materials is one of major challenges for practical ARFBs. Inorganic polysulfide is promising for ARFBs owing to its low cost and high solubility. However, it suffers from severe crossover resulting in low coulombic efficiency and limited lifespan. Organosulfides are more resistant to crossover than polysulfides owing to their bulky structures, but they suffer from slow reaction kinetics. Herein, we report a thiolate negolyte prepared by an exchange reaction between a polysulfide and an organosulfide, preserving low crossover rate of the organosulfide and high reaction kinetics of the polysulfide. The thiolate denoted as 2-hydroxyethyl disulfide+potassium polysulfide (HEDS+K2S2) shows reduced crossover rate than K2S2, faster reaction kinetics than HEDS, and longer lifespan than both HEDS and K2S2. The 1.5 M HEDS+1.5 M K2S2 static cell demonstrated 96 Ah L-1negolyte over 100 and 200 cycles with a high coulombic efficiency of 99.2% and 99.6% at 15 and 25 mA cm-2, respectively. The 0.5 M HEDS+0.5 M K2S2 flow cell delivered a stable and high capacity of 30.7 Ah L-1negolyte over 400 cycles (691 h) at 20 mA cm-2. This study presents an effective strategy to enable low-crossover and fast-kinetics sulfur-based negolytes for advanced ARFBs.

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A Self-Mediating Redox Flow Battery: High-Capacity Polychalcogenide-Based Redox Flow Battery Mediated by Inherently Present Redox Shuttles

Cited by 23 publications

References 48 publications

Redox Targeting of Energy Materials for Energy Storage and Conversion

Redox Targeting of Energy Materials for Energy Storage and Conversion

Material Design of Aqueous Redox Flow Batteries: Fundamental Challenges and Mitigation Strategies

A Low-Crossover and Fast-Kinetics Thiolate Negolyte for Aqueous Redox Flow Batteries

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