Phase Inversion Strategy to Fabricate Porous Carbon for Li‐S Batteries via Block Copolymer Self‐Assembly

Abstract

AbstractIn this paper, an easy, facile way of preparing porous carbon cathode for lithium–sulfur batteries with superior cycle stability is demonstrated. The highly porous cathode is fabricated by using self‐assembled nanostructured block copolymer as template. The block copolymer template is formed via phase inversion route followed by filling the empty spaces by oligomeric phenolic resin, thermopolymerization of the resin, and finally by carbonization. Semi‐gelled film of self‐assembled block copolymer is immersed in solution of nonsolvent mixture. After washing away of low molecular additive, a highly porous mat is generated. After successful filling with carbon precursor inside the template, crosslinking and carbonization under inert atmosphere result in a highly porous carbon material, which is further hybridized with sulfur via melt diffusion of elemental sulfur. This new fabrication route of template formation by phase inversion requires no solvent/thermal annealing step to generate nanostructure aided by block copolymer. The cathode material shows excellent cycle stability over 240 charging–discharging cycles, rate handling over 100 cycles.