Bi-Functional Diaminopropane Additive Enables Stable Li Anodes and Highly Efficient Cathodes for High-Performance Li-Air Batteries.

Low round-trip efficiency and limited cycle durability remain significant challenges for commercial of Lithium-air batteries (LABs). This study introduces a novel electrolyte additive, diaminopropane (DAP), that simultaneously addresses anode stability and cathode reaction kinetics in ambient LABs. The proposed mechanism involves a bi-function approach: 1) at the anode, DAP spontaneously reacts with metallic Li to form Li-DAP, which subsequently cross-links with ether solvents to create a protective gel layer. This layer effectively mitigates Li dendrite formation and shields the anode from ambient moisture and CO corrosion. 2) At the cathode, DAP modifies the oxygen reduction pathway from surface-mediated to solution-mediated, while simultaneously acting as an efficient redox mediator during charging. This dual functionality results in a remarkable reduction of the initial charging potential from 4.2 to 3.4 V, accompanied by observed singlet oxygen quenching. The implemented DAP additive enables LABs to achieve unprecedented cycling stability, demonstrating continuous operation for 1000 h in ambient air while maintaining energy efficiency exceeding 70%. This work establishes an effective electrolyte additive strategy for developing high-performance ambient LABs through simultaneous anode protection and enhanced cathode reaction reversibility.