Work

Conformational Control as a Design Strategy to Tune the Redox Behavior of Benzotriazole Negolytes for Nonaqueous Flow Batteries

Year: 2025

Type: article

Abstract: Here, we present a molecular engineering strategy to tune the reduction potentials of benzotriazole derivatives as high-energy-density negolytes in nonaqueous redox flow batteries. Within nonaqueous electrolytes, these derivatives, notably 2-( o -tolyl)-2 H -benzo[ d ][1,2,3]triazole ( 1 ), demonstrate a theoretical capacity of up to 93.8 Ah L –1 and a reduction potential of −2.35 V vs ferrocene/ferrocenium (Fc/Fc + ). Introducing dimethyl substitution (i.e., 2-(2,6-dimethylphenyl)-2 H -benzo[ d ][1,2,3]triazole ( 4 )) shifts the reduction potential even more negatively to −2.55 V vs Fc/Fc + . We ascribe the nonlinear effect of dimethyl substitution on reduction potential to ground-state conformational effects. Flow battery tests with negolyte 1 and ferrocene posolyte demonstrated >90% Coulombic efficiency at 6.7 mA cm –2 with improved cyclability in the presence of lithium bis(trifluoromethylsuylfonyl)imide supporting salt.

Source: ACS Applied Materials & Interfaces

DOI: 10.1021/acsami.4c21622