A Carbonyl-Rich Conjugated Microporous Polymer for Highly Efficient Lithiumion Storage

Abstract

Organic electrode materials are promising candidates for lithium-ion batteries (LIBs) due to their structural tunability and inherent flexibility. However, their practical application is hindered by poor electronic conductivity and the dissolution of active species. Herein, we report the rational design of a 2D carbonyl-functionalized graphyne (CfGY), constructed from a conjugated carbon skeleton and abundant carbonyl active sites via a Sonogashira cross-coupling reaction. The conductive sp–sp² hybridized backbone, hierarchical mesoporous network and expanded interlayer spacing jointly facilitate rapid electron conduction (E_g = 1.95 eV) and Li⁺ migration (D_Li⁺ = 1 × 10^–11 cm² s^–1). Synergistic lithium storage across carbonyl groups, alkyne linkages and aromatic rings reinforces structural robustness and elevates reversible capacity. After 340 cycles at 0.1 A g^–1, the self-supporting CfGY electrode retains a high capacity of 987 mAh g^–1, while sustaining steady 420 mAh g^–1 over 800 long cycles at 1 A g^–1 with negligible capacity decay. This backbone functionalization strategy unifies framework conductivity and multisite redox reactivity, delivering a generalizable guideline for developing high-stability, high-capacity organic anodes for next-generation lithium-ion batteries.