Enhanced Cycling Performance of Li–O₂ Battery by Using a Li₃PO₄-Protected Lithium Anode in DMSO-Based Electrolyte

Lithium–oxygen batteries (LOBs) have attracted increasing interest because of their superior theoretical specific energy. However, the stability of lithium metal anode is one of the obstacles limiting their practical applications. Here, we introduce an artificial Li3PO4 solid electrolyte interphase (SEI) film to protect the lithium anode in LOB with LiI/LiNO3/DMSO (dimethyl sulfoxide) electrolyte. The Li3PO4-protected Li anode exhibits excellent electrochemical stability during the Li stripping/plating process and leads to a relatively uniform and featureless surface in LOB after cycling. Our research demonstrates that superior electrochemical performance can be achieved in the Li–O2 battery with the synergistic combination of the DMSO-based electrolyte, the LiI redox mediator, and the Li3PO4-protected Li anode. The LOB with a Li3PO4-protected Li anode exhibits a prolonged cycling life span of 152 cycles with a fixed capacity of 1000 mA h g–1 at 2 A g–1. The results in this work provide knowledge for the development of a robust strategy for protecting the Li anode in the applications of Li–O2 batteries.