Work

Toward pH Versatile, Imidazole‐Based Posolytes for Aqueous Organic Redox Flow Batteries

Year: 2026

Type: article

Abstract: The use of organic redox species has emerged as a promising strategy to improve the sustainability of redox flow batteries (RFBs). Several organic redox species have been developed for the negative half‐cell of aqueous RFBs. However, the number of organic species available for the positive half‐cell—so‐called posolytes—is limited. In this study, different imidazole‐based compounds were synthesized from inexpensive starting materials and investigated for their suitability as posolytes in aqueous RFBs. Out of the imidazole‐based compounds assessed, 4‐(4,5‐diphenyl‐1H‐imidazol‐2‐yl)phenol was synthesized on a multigram scale and demonstrated sufficient solubility (0.53 M) in aqueous media. The aforementioned compound was found to display reversible electrochemical performance with standard reduction potential of +0.22 and +0.73 V versus standard hydrogen electrode (SHE), in 1 M KOH and 1 M AcOH, respectively. While chemical degradation of the oxidized species was observed during RFB cycling in 1 M KOH media no chemical degradation was perceived in 1 M AcOH, highlighting a pH‐dependent stability.

Source: Batteries & Supercaps

DOI: 10.1002/batt.202500775

Authors: Darius Pakarinen, Helena Lundberg, Amirreza Khataee

Institution: KTH Royal Institute of Technology

Language: English

Topic: Advanced battery technologies research

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: hybrid

Estimated APC paid: $4,030