A high potential biphenol derivative cathode: toward a highly stable air-insensitive aqueous organic flow battery

Aqueous organic flow batteries have attracted dramatic attention for stationary energy storage due to their resource sustainability and low cost. However, the current reported systems can normally be operated stably under a nitrogen or argon atmosphere due to their poor stability. Herein a stable airinsensitive biphenol derivative cathode, 3,30,5,50-tetramethylaminemethylene-4,40-biphenol (TABP), with high solubility (>1.5 mol L-1) and redox potential (0.91 V vs. SHE) is designed and synthesized by a scalable one-step method. Paring with silicotungstic acid (SWO), an SWO/TABP flow battery shows a stable performance of zero capacity decay over 900 cycles under the air atmosphere. Further, an SWO/TABP flow battery manifests a high rate performance with an energy efficiency of 85% at a current density of 60 mA cm(-2) and a very high volumetric capacity of more than 47 Ah L-1. This work provides a new and practical option for next-generation practical large-scale energy storage. (C) 2020 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.

Automated summary

An air-insensitive biphenol derivative cathode, TABP, with high solubility and redox potential has been designed and synthesized by a scalable one-step method. Coupled with silicotungstic acid, an SWO/TABP flow battery exhibits stable performance under an air atmosphere, showing high rate performance and a very high volumetric capacity. This work presents a practical option for next-generation large-scale energy storage.