High-performance zinc bromine flow battery via improved design of electrolyte and electrode

M. C. Wu, T. S. Zhao, H. R. Jiang, Y. K. Zeng, Y. X. Ren

Research output: Journal article publicationJournal articleAcademic researchpeer-review

70 Citations (Scopus)

Abstract

The zinc bromine flow battery (ZBFB) is regarded as one of the most promising candidates for large-scale energy storage attributed to its high energy density and low cost. However, it suffers from low power density, primarily due to large internal resistances caused by the low conductivity of electrolyte and high polarization in the positive electrode. In this work, chloride based salts including KCl and NH4Cl are investigated as supporting electrolyte to enhance electrolyte conductivity, while graphite-felt electrodes are thermally treated to improve electrocatalytic activity. It is found that the use of 4 M NH4Cl as a supporting electrolyte enables the battery to be operated at a current density of 40 mA cm−2 with an energy efficiency of 74.3%, whereas without the addition of a supporting electrolyte the battery only outputs an energy efficiency of 60.4%. In combination with a thermally treated graphite-felt electrode, efficiency further reaches up to 81.8% at the same current density. More impressively, we demonstrate that even at a high current density of up to 80 mA cm−2, the battery is capable of delivering an energy efficiency of 70%, representing one of the highest performances of ZBFBs in the open literature.

Original languageEnglish
Pages (from-to)62-68
Number of pages7
JournalJournal of Power Sources
Volume355
DOIs
Publication statusPublished - 2017
Externally publishedYes

Keywords

  • Electrolyte conductivity
  • Energy storage
  • Graphite felt electrode
  • Thermal treatment
  • Zinc bromine flow battery

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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