Title: Controlling Reversible Expansion of Li₂O₂ Formation and Decomposition by Modifying Electrolyte in Li-O₂ Batteries

Authors: Xiaodong Lin,Ruming Yuan, Yong Cao, Xiaobing Ding, Senrong Cai, Bowen Han, Yuhao Hong, Zhiyou Zhou, Xulai Yang, Lei Gong, Mingsen Zheng, QuanfengDong

Abstract:

The aprotic lithium-oxygen (Li-O₂) battery has attracted worldwide attention because of its ultrahigh theoretical energy density. However, its practical application is critically hindered by cathodepassivation, large polarization, and severe parasitic reactions. Here, we demonstrate an originally designed Ru(II) polypyridyl complex (RuPC) though which the reversible expansion of Li₂O₂ formation and decomposition can be achieved in Li-O₂ batteries. Experimental and theoretical results revealed that the RuPC can not only expand the formation of Li₂O₂ in electrolyte but also suppress the reactivity of LiO₂ intermediate during discharge, thus alleviating the cathode passivation and parasitic reactions significantly. In addition, an initial delithiation pathway can be achieved when charging in turn; thus, the Li₂O₂ products can be decomposed reversibly with a low overpotential. Consequently, the RuPC-catalyzed Li-O₂ batteries exhibited a high discharge capacity, a low charge overpotential, and an ultralong cycle life. This work provides an alternative way of designing the soluble organic catalysts for metal-O₂ batteries.

Full-link:https://www.sciencedirect.com/science/article/pii/S2451929418303826