A Rotating Cathode with Periodical Changes in Electrolyte Layer Thickness for High‐Rate Li‒O₂ Batteries

AbstractLi‒O2 batteries possess the highest theoretical gravimetric energy density among all types of secondary batteries, but they are still far from practical applications. The poor rate performance resulting from the slow mass transfer is one of the primary obstacles in Li‒O2 batteries. To solve this issue, we have designed a rotating cathode with periodic changes of the electrolyte layer thickness, decoupling the maximum transfer rate of Li+ and O2. During rotating, the thinner electrolyte layer on cathode facilitates the O2 transfer and the thicker electrolyte layer enhances the Li+ transfer. As a result, the rotating cathode enables the Li–O2 batteries to undergo 58 cycles at 2.5 mA cm–2 and discharge stably even at a high current density of 7.5 ‍mA ‍cm–2. Besides, it also makes the batteries exhibit a large discharge capacity of 6.8 ‍mAh ‍cm‒‍2, and the capacity decay is much slower with increasing current density. Notably, this rotating electrode holds great promise for utilization in other electrochemical cells involving gas‐liquid‐solid triple‐phase interfaces, suggesting a viable approach to enhance the mass transfer in such systems.This article is protected by copyright. All rights reserved