7.9 µm Turing Membranes with High Ion Conductivity for High Power Density Zinc‐Based Flow Battery

Abstract

Ion conductive membranes with rapid and selective ion transport are in high demand for high‐power energy storage devices. Surface periodic Turing microstructures are scientifically compelling for their high specific surface area which can promote ion transport of membranes. Here, high‐conductivity thin Turing membranes prepared by Co2+ coordination with polybenzimidazole (OPBI) are designed and their efficient ion transport in the alkaline zinc‐iron flow battery (AZIFB) is demonstrated. In this design, the Turing structure increases the effective contact area with the electrolyte, and the 7.9 µm thickness shortens the transmembrane pathway for ions. Molecular dynamics simulations further show that Co2+‐coordination enlarges the inner‐chain volume of membranes and forms continuous water channels for rapid ion transport. The boosting effect of membranes with high ion conductivity is proven by the peak power density and energy efficiency of the AZIFB, which shows an ultrahigh peak power density of 1147 mW cm−2 and demonstrates an energy efficiency of 80% even at a high current density of 200 mA cm−2.

Acid-Doped Pyridine-Based Polybenzimidazole as a Positive Triboelectric Material with Superior Charge Retention Capability

“…Meanwhile, the −NH– groups also confer adsorption capabilities of PBI to various ions, which has been applied in fuel cells, − gas separation, − flow batteries, − and so on. − Here, an ion chimera strategy is proposed by embedding and doping various ions into PBI to enhance the charge retention capability of PBI films. The benzimidazole groups in PBI chains have base functionalities and can embed and react with protic acids such as H 3 PO 4 , H 2 SO 4 , and HCl to form a protic polybenzimidazolium (Figure a).…”

Multifunctional Cellulose Nanocrystals Electrolyte Additive Enable Ultrahigh‐Rate and Dendrite‐Free Zn Anodes for Rechargeable Aqueous Zinc Batteries

“…[3] These issues manifest primarily as uncontrollable dendritic growth, rampant side reactions, furious Zn corrosion, as well as unsatisfactory plating/stripping behaviors (Figure 1a), resulting in poor coulombic efficiency (CE) and weak battery life, particularly under high current densities and capacities. [4] To stabilize the Zn chemistry, several strategies have been established: (1) structure engineering (Zn foil, [5] Zn powder, [6] Zn alloy, [7] 3D scaffolds [8] ), (2) surface modification (in situ [9] and ex situ protective layers [10] ), (3) electrolyte optimization (deep-eutectic electrolytes, [11] "water-in-salt" electrolytes, [12] molecular-crowding electrolytes, [13] and functional electrolyte additives [14] ), (4) advanced separators (glass fiber films, [15] polypropylene membranes, [16] polybenzimidazole membranes, [17] polyacrylonitrile films, [18] Nafionand cellulose-based separators [19] ). Among these strategies, functional electrolyte additives play a crucial role in regulating the Zn coordination environment and optimizing the electrode/electrolyte interface for uniform Zn deposition, because of its effectiveness, simple procedure, and easy implementation.…”

Multifunctional Cellulose Nanocrystals Electrolyte Additive Enable Ultrahigh‐Rate and Dendrite‐Free Zn Anodes for Rechargeable Aqueous Zinc Batteries

“…[3] These issues manifest primarily as uncontrollable dendritic growth, rampant side reactions, furious Zn corrosion, as well as unsatisfactory plating/stripping behaviors (Figure 1a), resulting in poor coulombic efficiency (CE) and weak battery life, particularly under high current densities and capacities. [4] To stabilize the Zn chemistry, several strategies have been established: (1) structure engineering (Zn foil, [5] Zn powder, [6] Zn alloy, [7] 3D scaffolds [8] ), (2) surface modification (in situ [9] and ex situ protective layers [10] ), (3) electrolyte optimization (deep-eutectic electrolytes, [11] "water-in-salt" electrolytes, [12] molecular-crowding electrolytes, [13] and functional electrolyte additives [14] ), (4) advanced separators (glass fiber films, [15] polypropylene membranes, [16] polybenzimidazole membranes, [17] polyacrylonitrile films, [18] Nafionand cellulose-based separators [19] ). Among these strategies, functional electrolyte additives play a crucial role in regulating the Zn coordination environment and optimizing the electrode/electrolyte interface for uniform Zn deposition, because of its effectiveness, simple procedure, and easy implementation.…”