Aqueous zinc−iodine batteries, featuring high energy density, safety, and cost-effectiveness, have been regarded as a promising energy storage system. Nevertheless, poor cycling stability and dissolution of iodine/polyiodide have greatly limited the development of zinc−iodine batteries. Here, iodine encapsulated by hierarchical porous carbon is employed as a positive material to assemble high-performance zinc−iodine batteries. Meanwhile, the utilization of the ZnI 2 additive in the electrolyte can enhance the capacity and cycling stability of as-assembled devices because the existence of polyiodide (I 3 − and I 5 − ) can effectively inhibit the dissolution of iodine. Thanks to the high conductivity and interconnected structure of the prepared carbon material, the asassembled zinc−iodine batteries deliver an excellent specific capacity of 360.6 mA h g −1 at 0.5 C, a superb durability (∼98.4% retention of the initial capacity at a high density of 50 C after 35,000 cycles), and an ultra-high energy/power density of 422.6 W h kg −1 /21.6 kW kg −1 . Significantly, the mechanism of the constructed device was investigated by ex-situ Raman and ex-situ X-ray diffraction. Besides, when coupling carbon@I 2 electrodes with the hydrogel electrolyte to assemble quasi-solid-state zinc−iodine batteries, the as-built device can well service for an electronic clock.

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To satisfy the increasing demand for higher energy density, the fabrication and structural designs of three‐dimensional (3D) thick electrodes have received considerable attention. In this work, cheap commercial graphite (Gt) and silicon monoxide (SiO) were chosen as raw materials. We have took advantage of the multi‐layer biscuit structure feature to the 3D Gt@GS (Gt@Gt/SiO) electrode with high loading through a modified 3D printing technology. Such a unique structure can not only effectively accommodate the volume expansion in all directions, but also provide a 3D transport channel to enhance the mobility of electrons and ions in the thick electrodes. The obtained 3D Gt@GS electrode, as a freestanding material, shows high capacity and good cycling stability. Especially, the 3D Gt@GS electrode after 120 cycles has achieved a reversible capacity of 3.52 mAh cm−2 at 3.6 mA cm−2. In addition, we have successfully fabricated a 3D plane‐shaped batteries via a direct ink writing technology and a fused deposition technology. The heterotypic battery assembled can be utilized as an external power supply for the aircraft model. This work demonstrates that the structural battery combined with structural load and 3D printing technology is versatile enough to meet the demand of energy storage systems for high energy density.

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