Realizing Formation and Decomposition of Li2O2 on Its Own Surface with a Highly Dispersed Catalyst for High Round-Trip Efficiency Li-O2 Batteries

The rapid and effective formation and decomposition of Li 2 O 2 during cycling is crucial to solve the problems associated with the practical limitation of lithium-oxygen (Li-O 2 ) batteries. In this work, a highly dispersed electrocatalyst with Ru nanoclusters inside the special organic molecular cage (RuNCs@RCC3) through a reverse double-solvent method for Li-O 2 batteries has been proposed for the first time. This RuNCs@RCC3 shows an effective catalyst enabling reversible formation and decomposition of the Li 2 O 2 at the interface between the Li 2 O 2 and the liquid electrolyte, rather than the sluggish solid-solid interface reactions on commonly used solid catalysts. As a result, the Li-O 2 cells with RuNCs@RCC3 show enhanced electrochemical performance, including low overpotential (310 mV at a current density of 100 mA g −1 ), high specific capacity (15,068 mAh g −1 ), good rate capability (1,800 mAh g −1 at a current density of 2.8 A g −1 ), and especially superior cycle stability up to 470 cycles.