Modulated Zn Deposition by Glass Fiber Interlayers for Enhanced Cycling Stability of Zn–Br Redox Flow Batteries

Abstract

The zinc bromine redox flow battery (ZBB) is one of the most promising candidates for next-generation energy storage systems due to its low cost, inflammability, and high power and energy densities. However, dendritic Zn growth, which intensifies at higher current densities and larger deposition capacities, practically hinders the high-current and high-capacity operation of ZBBs. Herein, we demonstrate that a non-conductive, highly porous, and zincophilic glass fiber (GF) layer on top of a carbon felt electrode notably suppresses dendritic Zn growth. The ZBB with the GF layer successfully operates for more than 4000 cycles at 80 mA cm −2 and 20 mA h cm −2 , in contrast to the cell failure outcome at the 45th cycle for a GF-free ZBB. Electrochemical analysis and simulations suggest that the surface polar groups of the GF facilitate Zn ion transport and matrix-guided Zn deposition. A GF layer decorated with negatively charged polymer achieves highly superior uniform Zn deposition and remarkable cycling stability at 200 mA cm −2 and 50 mA h cm −2 , verifying the validity of this approach.

Zincophilic Design and the Electrode/Electrolyte Interface for Aqueous Zinc‐Ion Batteries: A Review

“…Due to the superiority of the designed spacers, the reversibility and stability of the zinc metal anode was excellent without dendrites. Kim et al [78] proposed that the large pore sizes of GF separators are capable of accommodating large numbers of aqueous electrolytes. The silicate fibers have a highly zincophi-licity and facilitates the transport of the Zn ions.…”

Functionalized metal–organic framework modified membranes with ultralong cyclability and superior capacity for zinc/bromine flowless batteries

“…In the course of the electroplating of metallic Zn on the anode for charging, Zn dendrites can grow due to localized current, resulting in a short circuit. [7][8][9] Furthermore, ZBFLBs suffer from an augmented crossover of bromine (Br 2 ) and polybromide (Br n − ) formed on the cathode through the membrane, causing self-discharge and a consequent decrease in coulombic efficiency (CE). 8,10,11 In addition, the Br 2 /Br n − crossover deteriorates anode reversibility from Zn corrosion, forming dead Zn.…”

“…[7][8][9] Furthermore, ZBFLBs suffer from an augmented crossover of bromine (Br 2 ) and polybromide (Br n − ) formed on the cathode through the membrane, causing self-discharge and a consequent decrease in coulombic efficiency (CE). 8,10,11 In addition, the Br 2 /Br n − crossover deteriorates anode reversibility from Zn corrosion, forming dead Zn. 5,12 To address these problems, the membrane in ZBFLBs should transport Zn 2+ uniformly and suppress the crossover, 13 which underscores the importance of membrane technology in ZBFLB research.…”

Nanocatalyzed PtNi Alloy Intact @3D Graphite Felt as an Effective Electrode for Super Power Redox Flow Battery

“…It can be addressed by managing the interface amongst the anodes, and electrolytes can prevent zinc dendrite formation. [ 11 ] A non‐conductive, highly porous, and zincophilic glass fiber layer on the carbon felt electrode notably suppresses the dendrite Zn growth; [ 12 ] Cr 3+ was also used as additive to minimize the zinc dendrite growth and hydrogen evolution during galvanostatic charge–discharge (GCD) process in the anode. [ 13 ] Additive (4 m NH 4 Cl) incorporated electrolyte showed good energy efficiency (EE) of 74.3% at 40 mA cm −2, whereas, additive free electrolyte, the battery led only about 60.4%.…”

“…[ 13 ] Additive (4 m NH 4 Cl) incorporated electrolyte showed good energy efficiency (EE) of 74.3% at 40 mA cm −2, whereas, additive free electrolyte, the battery led only about 60.4%. [ 12 ] The restrictive operating current density of ZBFB is because of the passive reversibility of Br 2 /Br − conversion and its results in significant positive side polarization. Therefore, it needs to progress the highly functional material improving the kinetics of Br 2 /Br − then; it results in high power density.…”