Pseudocapacitive Heteroatom-Doped Carbon Cathode for Aluminum-Ion Batteries with Ultrahigh Reversible Stability

Aluminum (Al)-ion batteries have emerged as a potential alternative to conventional ion batteries that rely on less abundant and costly materials like lithium. Nonetheless, given the nascent stage of advancement in Al-ion batteries (AIBs), attaining electrode materials that can leverage both intercalation capacity and structural stability remains challenging. Herein, we demonstrate a C₃N₄-derived layered N,S heteroatom−doped carbon, obtained at different pyrolysis temperatures, as a cathode material for AIBs, encompassing the diffusion−controlled intercalation and surface-induced capacity with ultrahigh reversibility. The developed layered N,S-doped corbon (N,S-C) cathode, synthesized at 900 °C, delivers a specific capacity of 330 mAh g⁻¹ with a relatively high coulombic efficiency of ~85% after 500 cycles under a current density of 0.5 A g⁻¹. Owing to its reinforced adsorption capability and enlarged interlayer spacing by doping N and S heteroatoms, the N,S-C900 cathode demonstrates outstanding energy storage capacity with excellent rate performance (61 mAh g⁻¹ at 20 A g⁻¹) and ultrahigh reversibility (90 mAh g⁻¹ at 5 A g⁻¹ after 10 000 cycles).