Copper-tailored d-p-π multi-orbital coupling in sulfurized polyaniline enables ultralong cycling aqueous sulfur batteries

The practical application of sulfur-based batteries is significantly limited by sluggish reaction kinetics and structural collapse. Herein, a copper-modified sulfurized polyaniline (CuSPANI) cathode with distinctive d-p-π multi-orbital coupling is constructed through Cu heteroatom introduction. This coupling, arising from hybridization between Cu d orbitals and sulfurized polyaniline (SPANI) p/π orbitals, enables triple electronic modulation: reducing energy barriers to enhance kinetics, expanding electron delocalization to improve conductivity, and activating horizontal Cu d orbitals to strengthen structural stability. Consequently, the aqueous CuSPANI battery delivers a high reversible capacity of 834.75 mAh g s −1 at 3 C and exceptional cycling stability (61.2% capacity retention after 60,000 cycles at 15 C). Moreover, the designed flexible quasi-solid-state pouch cell achieves a 1.25 V output and maintains stable power under deformation, highlighting its potential for wearable energy storage. This work provides new insight into designing high-performance sulfurized polymers via orbital hybridization.