Effective Design Strategy of Small Bipolar Molecules through Fused Conjugation toward 2.5 V Based Redox Flow Batteries

摘要

Using bipolar redox-active molecules (BRMs) asactive materials is a practical way to address electrolyte crossoverand resultant unpredictable side reactions in redox-flowbatteries. However, the development of BRMs is greatly hinderedby difficulties infinding new molecules from limited redox-activemoieties and in achieving high cell voltage to compete withexistingflow battery chemistries. This study proposes a strategyfor design of high-voltage BRMs using fused conjugation thatregulates the redox potential of integrated redox-active moieties.As a demonstration, quaternary N and ketone redox moieties areused to construct a new BRM that shows a prominent voltagegap with good electrochemical stability. A symmetrical redox-flow cell based on this molecule exhibits a high voltage of 2.5 Vand decent cycling stability. This study provides a general strategy for designing new BRMs that may enrich the cellchemistries of organic redox-flow batteries.

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