Structural evolution and electrolyte engineering for tri-electrolyte zinc-air cells

Zinc air cell (ZAC) is a promising alternative for Li-ion battery owing to its superior energy density, while it suffers from alkaline electrolyte related issues. Here, a tri-electrolyte microfluidic zinc-air cells are developed based on structural evolution and electrolyte engineering. By strategically using acidic catholyte instead of alkalis, the device performance is largely improved and stabilized, benefiting from 0.8V higher cathodic reaction potential and prohibited carbonate contamination. Since alkalis are still preferred for the anolyte, a third bridge-electrolyte is applied to avoid the neutralization of two electrolytes. To avoid using membranes, a microfluidic cell configuration is further integrated. Without the ion-restriction of the membranes, H₂SO₄ becomes applicable for catholyte and contributes to a stable operation with further improved potential of 2.18 V. Furthermore, the electrolyte mixing behavior is investigated from both experimental and simulation aspects, which demonstrates the recyclability of the electrolytes and provides guidance for the real application.