Breaking the Reversibility Barrier in Zn-Air Systems With Dual-Electrolyte Engineering

In response to the escalating demand for advanced energy storage solutions and the pursuit of safer, more sustainable alternatives to conventional lithium-ion batteries, addressing the reversibility and stability challenges of Zn anodes in Zn-air batteries has become imperative. To tackle these issues, particularly under alkaline conditions, a unique separated Zn-air system (SZAS) is demonstrated. This system conducts the charging process in a near-neutral electrolyte, significantly suppressing hydrogen evolution reactions and dendrite growth while discharging occurs in an alkaline electrolyte to maximize voltage output. This design effectively addresses passivation layer formation and prolongs cathode lifespan by preventing catalyst deactivation and element loss during high-voltage oxygen evolution reactions (OER). The SZASs demonstrate a 99.84% Coulombic efficiency over 5000 cycles in nearly neutral electrolytes and a discharging energy density reaching 218 Wh kg^-1 in alkaline electrolyte, showing promise in advanced energy storage techniques. Additionally, replacing OER with iodine oxidation reaction reduces charging voltage to 1.5 V and achieves a 3.7 V output via serial discharging. This work proposes the separation engineering of battery architectures, integrating benefits from diverse electrolyte environments, and paves the way for aligning advancements in energy storage, waste management, material recycling, and sustainable power solutions for electric vehicles.