Composites of azo-linked pyrene-tetraone porous organic polymers as cathodes for lithium-ion batteries†

Abstract

Organic redox-active polymers offer a potentially sustainable and cost-effective alternative to conventional inorganic electrode materials in rechargeable batteries, yet they struggle with low conductivity and stability. Here, we present a novel porous polymer with dual functionality to overcome these challenges. This polymer incorporates carbonyl (CO) groups as redox-active units and azo (NN) groups as linkers, enhancing ion/electron transport and electrode stability by extending conjugation and reducing unused mass. Additionally, carbon nanotubes (CNTs) are integrated into these composites to further increase conductivity, leveraging their exceptional electrical properties. We synthesized azo-linked pyrene-tetraone porous polymers with varying CNT loadings (0%, 30%, and 50%), termed Azo-PTP, Azo-PTP30, and Azo-PTP50, respectively, as cathode materials for organic lithium-ion batteries. Our study demonstrates that Azo-PTP50, with 50% CNTs, achieves a two-fold increase in specific capacity compared to its CNT-free counterpart and maintains superior capacity retention over 200 cycles and 93% retention over 1000 cycles, displaying its enhanced performance and stability.