Supramolecularly Confined Catalysis in Polyphthalocyanine‐Crown‐Ether Frameworks Boosts Sulfur Redox Kinetics

Abstract

Abstract Metal phthalocyanines are considered as potent catalysts in lithium–sulfur (Li–S) chemistry. However, their adsorption capability is deficient to inhibit polysulfides from shuttling, which in turn retards the S‐redox reaction in the cathode. Here we report flexible, two‐dimensional (2D) polyphthalocyanine‐crown‐ether (PPc‐CE) frameworks that provide a supramolecularly confined space created with the single‐atom catalytic nickel phthalocyanine nodes and crown‐ether linkers as Li host. Electrochemical and theoretical analyses reveal that a cooperative redox catalysis with the enhanced lithiophilicity of PPc‐CE‐coated carbon nanotubes (PPc‐CE/CNTs) boosts Li–S redox kinetics and, meanwhile, suppresses the growth of Li dendrites for the long term. A Li||S cell employing PPc‐CE/CNT catalysts delivers a high discharge capacity of 1,363 mAh g −1 at 0.1C and still retains a specific capacity of ∼700 mAh g −1 over 500 cycles at 1C. Our work provides insights into the molecular design of redox catalysts for Li–S batteries based on 2D polymers.