Hybridization State Engineering of Coal Pitch-Based Carbon Materials Enabling Ultrastable Aqueous Zinc–Iodine Batteries with 150,000 Cycles

Carbon materials with superior porosity and conductivity are widely adopted in aqueous zinc–iodine batteries to host iodine, but suffer from the polyiodide shuttle and cycling stability challenges. Traditional strategies mainly focus on pore structure engineering or heteroatom doping of carbon hosts to confine iodine, but fail to address the sluggish iodine conversion kinetics. Herein, we initially reveal the significant yet overlooked role of hybridization state in reforming the carbon intrinsic activity toward high-efficiency iodine conversion chemistry. With pitch-derived porous carbon as an example, we controllably regulate the C(sp2)/C(sp3) ratio (from 1.23 to 2.21) while maintaining high surface area. These properties lower the activation energy of iodine conversion and effectively suppress the polyiodide shuttle. The zinc–iodine battery exhibits ultrahigh cycling stability after 150,000 cycles and a low self-discharging rate with only 12.5% capacity loss after 20 days. Ah-level pouch cell with 66.6 mgiodine cm–2 achieves a cumulative discharging capacity of 103.51 Ah. The hybridization engineering was successfully extended to commercial porous carbon (YP-50F), prolonging the lifespan from 7425 to 27,000 cycles. This work presents a hybridization state engineering strategy to reform the intrinsic activity of the carbon host to favor the iodine conversion chemistry and beyond.