Abstract
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 AlCl(3) /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 AlCl(2) (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.