Heterocyclic Conjugated Polymer Nanoarchitectonics with Synergistic Redox-Active Sites for High-Performance Aluminium Organic Batteries

The development of cost-effective and long-life rechargeable aluminium ion batteries (AIBs) shows promising prospects for sustainable energy storage applications. Here, we report a heteroatom π-conjugated polymer featuring synergistic C=O and C=N active centres as a new cathode material in AIBs using a low-cost AlCl₃/urea electrolyte. Density functional theory (DFT) calculations reveal the fused C=N sites in the polymer not only benefit good π-conjugation but also enhance the redox reactivity of C=O sites, which enables the polymer to accommodate four AlCl₂(urea)₂⁺ per repeating unit. By integrating the polymer with carbon nanotubes, the hybrid cathode exhibits a high discharge capacity and a long cycle life (295 mAh g⁻¹ at 0.1 A g⁻¹ and 85 mAh g⁻¹ at 1 A g⁻¹ over 4000 cycles). The achieved specific energy density of 413 Wh kg⁻¹ outperforms most Al–organic batteries reported to date. The synergistic redox-active sites strategy sheds light on the rational design of organic electrode materials.