Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery

Redox flow batteries are receiving wide attention for electrochemical energy storage due to their unique architecture and advantages, but progress has so far been limited by their low energy density (~25 Wh l(-1)). Here we report a high-energy density aqueous zinc-polyiodide flow battery. Using the highly soluble iodide/triiodide redox couple, a discharge energy density of 167 Wh l(-1) is demonstrated with a near-neutral 5.0 M ZnI2 electrolyte. Nuclear magnetic resonance study and density functional theory-based simulation along with flow test data indicate that the addition of an alcohol (ethanol) induces ligand formation between oxygen on the hydroxyl group and the zinc ions, which expands the stable…

• UD
  U.S. Department of Energy

  Awards: 57558, 76RL01830, AC05-76RL01830, Contract DE-AC05-76RL01830, DE-AC05-76RL01830, DE-AC05
• B
  Battelle

  Awards: AC05-76RL01830, DE-AC05, DE-AC05-76RL01830, 57558
• OO
  Office of Electricity Delivery and Energy Reliability

  Awards: DE-AC05-76RL01830, 57558
• OO
  Office of Electricity

  Awards: DE-AC05-76RL01830, 57558
• BA
  Biological and Environmental Research

  Awards: AC05-76RL01830, 76RL01830, DE-AC05-76RL01830
• PN
  Pacific Northwest National Laboratory

  Awards: DE-AC05-76RL01830, 76RL01830