A TEMPO-anchored covalent organic framework towards high-performance lithium-oxygen batteries
Lili Liu, Keran Ge, Congcong Zhou, Meiying Kuai, Lanling Zhao, Yuntao Ding, Yuhui Chen, Weiwei Fang, Yuping Wu
Abstract
Soluble redox mediators (RMs), despite of the advantages in effectively catalyzing Li 2 O 2 formation/decomposition in lithium-oxygen batteries (LOBs), induce violet shuttle effect and Li corrosion. To address this issue, a 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO)-anchored covalent organic framework (TEMPO-COF) was synthesized for the first time as the cathode material towards high-performance lithium-oxygen batteries (LOBs). The TEMPO radicals immobilized on COFs via imine bonds guide the solution-phase generation pathway of discharge products. Upon cycling, it not only reduces overpotentials but also suppresses the shuttle effect of free TEMPO, effectively protecting the lithium anode from the corrosion of reactive intermediates. TEMPO-COF cathode retains superior radical activity in the electrolyte environment, leading to an extended cycle life of LOBs. This work not only presents an effective bifunctional electrocatalyst for LOBs, but also provides a promising strategy to anchor redox mediators via covalent bonds into COFs, yet shedding light on novel electrocatalyst design and broadening the application area of COFs.