Highly Reversible and Rechargeable Safe Zn Batteries Based on a Triethyl Phosphate Electrolyte.

Zinc metal is an attractive anode material for next-generation batteries. However, dendrite growth and limited Coulombic efficiency (CE) during cycling are the major roadblocks towards the widespread commercialization of batteries employing Zn anodes. In this work we report the novel adoption of triethyl phosphate (TEP) as a solvent and co-solvent with aqueous electrolytes to obtain a highly stable and dendrite-free Zn anode. Stable Zn plating/stripping for over 3000 h was obtained, accompanied by a CE of 99.68 %. SEM images of the Zn anodes revealed highly porous interconnected dendrite-free Zn deposits. The electrolyte displayed good compatibility with both Zn anodes and potassium copper hexacyanoferrate (KCuHCf) cathodes for Zn ion batteries (ZIBs). The full cell showed a long cycling stability and high rate capability. The present work is a contribution towards cost-effective and safe battery systems.