Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
Nat Commun. 2013;4:1943. doi: 10.1038/ncomms2941.
Silicon has a high-specific capacity as an anode material for Li-ion batteries, and much research has been focused on overcoming the poor cycling stability issue associated with its large volume changes during charging and discharging processes, mostly through nanostructured material design. Here we report incorporation of a conducting polymer hydrogel into Si-based anodes: the hydrogel is polymerized in-situ, resulting in a well-connected three-dimensional network structure consisting of Si nanoparticles conformally coated by the conducting polymer. Such a hierarchical hydrogel framework combines multiple advantageous features, including a continuous electrically conductive polyaniline network, binding with the Si surface through either the crosslinker hydrogen bonding with phytic acid or electrostatic interaction with the positively charged polymer, and porous space for volume expansion of Si particles. With this anode, we demonstrate a cycle life of 5,000 cycles with over 90% capacity retention at current density of 6.0 A g(-1).
硅作为锂离子电池的阳极材料具有高比容量，大量研究致力于克服其在充放电过程中因体积变化大而导致的循环稳定性差的问题，主要通过纳米结构材料设计来实现。在此，我们报告了将导电聚合物水凝胶引入硅基阳极中：水凝胶原位聚合，形成由 Si 纳米颗粒通过导电聚合物的共形包覆组成的良好连接的三维网络结构。这种分级水凝胶框架结合了多种优势特性，包括连续的导电聚苯胺网络，通过交联剂与植酸的氢键或与带正电荷的聚合物的静电相互作用与 Si 表面结合，以及用于 Si 颗粒体积膨胀的多孔空间。使用这种阳极，我们在 6.0 A g(-1)的电流密度下展示了 5000 次循环的寿命，容量保持率超过 90%。
