Liang Yu-Long, Yu Yue, Li Zi-Wei, Yang Dong-Yue, Liu Tong, Yan Jun-Min, Huang Gang, Zhang Xinbo
Key Laboratory of Automobile Materials, Ministry of Education, Department of Materials Science and Engineering, Jilin University, Changchun, 130022, China.
State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China.
Adv Mater. 2024 Aug;36(31):e2403230. doi: 10.1002/adma.202403230. Epub 2024 Apr 22.
Li-O batteries (LOBs) 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 LOBs. To solve this issue, a rotating cathode with periodic changes in the electrolyte layer thickness is designed, decoupling the maximum transfer rate of Li and O. During rotation, the thinner electrolyte layer on the cathode facilitates the O transfer, and the thicker electrolyte layer enhances the Li transfer. As a result, the rotating cathode enables the LOBs to undergo 58 cycles at 2.5 mA cm and discharge stably even at a high current density of 7.5 mA cm. Besides, it also makes the batteries exhibit a large discharge capacity of 6.8 mAh cm, 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.
锂-氧电池（LOBs）在所有类型的二次电池中具有最高的理论重量能量密度，但它们仍远未实现实际应用。由缓慢的传质导致的较差倍率性能是LOBs的主要障碍之一。为了解决这个问题，设计了一种电解质层厚度周期性变化的旋转阴极，使锂和氧的最大传输速率解耦。在旋转过程中，阴极上较薄的电解质层有利于氧的传输，而较厚的电解质层则增强锂的传输。结果，旋转阴极使LOBs在2.5 mA/cm²下能够进行58次循环，甚至在7.5 mA/cm²的高电流密度下也能稳定放电。此外，它还使电池表现出6.8 mAh/cm²的大放电容量，并且随着电流密度的增加，容量衰减要慢得多。值得注意的是，这种旋转电极在涉及气-液-固三相界面的其他电化学电池中具有很大的应用前景，这表明了一种增强此类系统中传质的可行方法。
