Breaking the capacity bottleneck of lithium-oxygen batteries through reconceptualizing transport and nucleation kinetics

The practical capacity of lithium-oxygen batteries falls short of their ultra-high theoretical value. Unfortunately, the fundamental understanding and enhanced design remain lacking, as the issue is complicated by the coupling processes between Li₂O₂ nucleation, growth, and multi-species transport. Herein, we redefine the relationship between the microscale Li₂O₂ behaviors and the macroscopic electrochemical performance, emphasizing the importance of the inherent modulating ability of Li⁺ ions through a synergy of visualization techniques and cross-scale quantification. We find that Li₂O₂ particle distributed against the oxygen gradient signifies a compatibility match for the nucleation and transport kinetics, thus enabling the output of the electrode’s maximum capacity and providing a basis for evaluating operating protocols for future applications. In this case, a 150% capacity enhancement is further achieved through the development of a universalizing methodology. This work opens the door for the rules and control of energy conversion in metal-air batteries, greatly accelerating their path to commercialization.