Bioinspired Starch‐Polyiodide Electrolytes for Self‐Healing Lithium‐Metal Interfaces and Stable Photoelectrochemical Energy Storage

ABSTRACT The development of high‐energy‐density power sources with integrated energy harvesting capabilities is crucial for advancing wearable electronics. Herein, inspired by the homeostatic ion regulation mechanisms of plant roots in dynamic chemical environments, we developed a biomimetic starch‐polyiodide solid polymer electrolyte for constructing an integrated photo‐rechargeable energy storage system. The incorporation of functionalized starch‐polyiodides reconfigures the PVDF matrix topology, modulates the all‐trans (TTTT) conformation and anchors anions, thereby optimizing lithium‐ion transport and enhancing ionic conductivity, while enabling interfacial dead‐lithium self‐healing at the anode and defect passivation of the photoelectrochemical storage cathode (PSC). In situ characterization and theoretical calculations revealed that the additive facilitated multi‐electron transfer and formed a functional buffer layer, which synergistically stabilized the lithium metal anode interface while suppressing ion migration at the PSC. This mechanism established a robust solid electrolyte interphase and improved the overall energy storage efficiency of the integrated device. The resulting flexible integrated device demonstrated outstanding performance, retaining 85% capacity and 95.2% energy efficiency after 450 cycles at 1 C while preserving superior mechanical flexibility and efficient photo‐electric conversion. This work provides a novel strategy for developing flexible energy storage systems that integrate high ionic conductivity, interfacial stability, and photo‐electrochemical synergy.