Key Laboratory of Superlight Material and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, Heilongjiang, China.
Nanoscale. 2017 Jul 13;9(27):9365-9375. doi: 10.1039/c7nr02311a.
Rechargeable sodium-iodine and lithium-iodine batteries have been demonstrated to be promising and scalable energy-storage devices, but their development has been seriously limited by challenges such as their inferior stability and the poor kinetics of iodine. Anchoring iodine to 3D porous carbon is an effective strategy to overcome these defects; however, both the external architecture and internal microstructure of the 3D porous carbon host can greatly affect the ion intercalation of iodine/C electrodes. To realize the full potential of iodine electrodes, a biochemistry-enabled route was developed to enable the controllable design of different 3D porous architectures, from hollow microspheres to 3D foam, for use in iodine/C cathodes. Two types of spores with spherical cells, i.e. Cibotium Barometz (C. Barometz) and Oetes Sinesis (O. Sinesis), are employed as bio-precursors. By carefully controlling the degree of damage on the bio-precursors, different targeted carbon hosts were fabricated. Systematic studies were carried out to clarify the structural effects on modifying the ion-intercalation capabilities of the iodine/C cathodes in lithium-iodine and sodium-iodine batteries. Our results demonstrate the profound performance improvements of both 3D bio-foam and hollow sphere because their hierarchically porous structures can strongly immobilize iodine. Notably, the 3D bio-foam based iodine composites achieve faster ion kinetics and enhanced rate capability than their hollow sphere based counterparts. This was attributed to their higher micro/mesopore volume, larger surface area and improved packing density, which result in the highly efficient adsorption of iodine species. By virtue of the thinnest slices, the iodine/bio-foam derived from C. Barometz spores achieves the best high-rate long-term cycling capability, which retains 94% and 91% of their capacities in lithium-iodine and sodium-iodine batteries after 500 cycles, respectively. With the help of the biochemistry-assisted technique, our study provides a much-needed fundamental insight for the rational design of 3D porous iodine/C composites, which will promote a significant research direction for the practical application of lithium/sodium-iodine batteries.
可充电的碘化钠和碘化锂电池已被证明是很有前途且可扩展的储能设备，但它们的发展受到稳定性差和碘动力学性能差等挑战的严重限制。将碘锚定在 3D 多孔碳上是克服这些缺陷的有效策略；然而，3D 多孔碳主体的外部结构和内部微观结构都可以极大地影响碘/C 电极的离子嵌入。为了充分发挥碘电极的潜力，开发了一种基于生物化学的方法，以实现不同 3D 多孔结构的可控设计，从空心微球到 3D 泡沫，用于碘/C 阴极。两种具有球形细胞的孢子，即 Cibotium Barometz（C. Barometz）和 Oetes Sinesis（O. Sinesis），被用作生物前体。通过仔细控制生物前体的破坏程度，制备了不同的目标碳宿主。进行了系统研究，以阐明结构效应对修饰锂碘和钠碘电池中碘/C 阴极的离子嵌入能力的影响。我们的结果表明，3D 生物泡沫和空心球的性能都得到了显著提高，因为它们的分级多孔结构可以强烈固定碘。值得注意的是，基于 3D 生物泡沫的碘复合材料具有更快的离子动力学和增强的倍率性能，优于其空心球基对应物。这归因于它们具有更高的微/介孔体积、更大的表面积和改进的堆积密度，从而实现了碘物种的高效吸附。得益于最薄的切片，源自 C. Barometz 孢子的碘/生物泡沫实现了最佳的高速长期循环能力，在锂碘和钠碘电池中分别经过 500 次循环后，其容量保留率分别为 94%和 91%。借助生物化学辅助技术，我们的研究为合理设计 3D 多孔碘/C 复合材料提供了急需的基础见解，这将为锂/钠碘电池的实际应用推动一个重要的研究方向。
