The redox couple of I⁰/I⁻ in aqueous rechargeable iodine–zinc (I₂-Zn) batteries is a promising energy storage resource since it is safe and cost-effective, and provides steady output voltage. However, the cycle life and efficiency of these batteries remain unsatisfactory due to the uncontrolled shuttling of polyiodide (I₃⁻ and I₅⁻) and side reactions on the Zn anode. Starch is a very low-cost and widely sourced food used daily around the world. “Starch turns blue when it encounters iodine” is a classic chemical reaction, which results from the unique structure of the helix starch molecule–iodine complex. Inspired by this, we employ starch to confine the shuttling of polyiodide, and thus, the I⁰/I⁻ conversion efficiency of an I₂-Zn battery is clearly enhanced. According to the detailed characterizations and theoretical DFT calculation results, the enhancement of I⁰/I⁻ conversion efficiency is mainly originated from the strong bonding between the charged products of I₃⁻ and I₅⁻ and the rich hydroxyl groups in starch. This work provides inspiration for the rational design of high-performance and low-cost I₂-Zn in AZIBs.

NiFe layered double hydroxide (NiFe-LDH) nanosheets and metal-nitrogen-carbon materials (M-N-C, M = Ni, Fe, Co, etc.) are supreme catalysts in the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) process, respectively. Nevertheless, the monotonic performance and insufficient stability severely hamper their practical application in rechargeable batteries. Herein, we simultaneously combine ultrathin NiFe-LDH nanowalls with renewable soybean-derived Fe-N-C matrix to obtain a hybrid materials (NiFe-LDH/FeSoy-CNSs-A), which exhibits robust catalytic activities for OER (E_j=10 = 1.53 V vs. RHE) and ORR (E_1/2 = 0.91 V vs. RHE), with a top-notch battery parameters and stability in assembled rechargeable Zn-air batteries. Intensive investigations indicate that the vertically dispersed NiFe-LDH nanosheets, Fe-N-C matrix derived from soybean and the strong synergy between them are responsible for the unprecedented OER and ORR performances. The key role of intrinsic N defects involved in the hybrid materials is firstly specified by ultrasoundassisted extraction of soy protein from soybean. The exquisite design can facilitate the utilization of sustainable biomass-derived catalysts, and the mechanism investigations of N defects and oxygenic groups on the structure-activity relationship can stimulate the progress of other functional hybrid electrocatalysts.