In this review,we focus on the conversion reaction in newly raised rechargeable lithium batteries instanced by lithium-sulfur and lithium-oxygen batteries.A comprehensive discussion is made on the fundamental electrochemistry and recent advancements in key components of both types of the batteries.The critical problems in the Li-S and Li-O2 conversion electrochemistry are addressed along with the corresponding improvement strategies,for the purpose of shedding light on the rational design of batteries to reach optimal performance.