Yang Qiao, Wu Xuhao, Huang Xuankai, Liao Shuang, Liang Kaijie, Yu Xueang, Li Kuan, Zhi Chunyi, Zhang Haiyan, Li Na
School of Material and Energy , Guangdong University of Technology , Guangzhou 510006 , P. R. China.
School of Materials Science and Energy Engineering , Foshan University , Foshan 528000 , P. R. China.
ACS Appl Mater Interfaces. 2019 Aug 28;11(34):30801-30809. doi: 10.1021/acsami.9b08111. Epub 2019 Aug 14.
Penetrating into the inner surface of porous metal-oxide nanostructures to encapsulate the conductive layer is an efficient but challenging route to exploit high-performance lithium-ion battery electrodes. Furthermore, if the bonding force on the interface between the core and shell was enhanced, the structure and cyclic performance of the electrodes will be greatly improved. Here, vertically aligned interpenetrating encapsulation composite nanoframeworks were assembled from Cl/SO-codoped poly(3,4-ethylenedioxythiophene) (PEDOT) that interpenetrated and coated on porous FeO nanoframeworks (PEDOT-IE-FeO) via a one-step Fe-induced in situ growth strategy. Compared with conventional wrapped structures and methods, the special PEDOT-IE-FeO encapsulation structure has many advantages. First, the codoped PEDOT shell ensures a high conductive network in the composites (100.6 S cm) and provides interpenetrating fast ion/electron transport pathways on the inner and outer surface of a single composite unit. Additionally, the pores inside offer void space to buffer the volume expansion of the nanoscale frameworks in cycling processes. In particular, the formation of Fe-S bonds on the organic-inorganic interface (between PEDOT shell and FeO core) enhances the structural stability and further extends the cell cycle life. The PEDOT-IE-FeO was applied as lithium-ion battery anodes, which exhibit excellent lithium storage capability and cycling stability. The capacity was as high as 1096 mA h g at 0.05 A g, excellent rate capability, and a long and stable cycle process with a capacity retention of 89% (791 mA h g) after 1000 cycles (2 A g). We demonstrate a novel interpenetrating encapsulation structure to highly enhance the electrochemical performance of metal-oxide nanostructures, especially the cycling stability, and provide new insights for designing electrochemical energy storage materials.
渗透到多孔金属氧化物纳米结构的内表面以封装导电层是开发高性能锂离子电池电极的有效但具有挑战性的途径。此外，如果核壳界面上的结合力得到增强，电极的结构和循环性能将得到极大改善。在此，通过一步铁诱导原位生长策略，由互穿并包覆在多孔FeO纳米框架上的Cl/SO共掺杂聚（3,4-乙撑二氧噻吩）（PEDOT）组装了垂直排列的互穿封装复合纳米框架（PEDOT-IE-FeO）。与传统的包裹结构和方法相比，特殊的PEDOT-IE-FeO封装结构具有许多优点。首先，共掺杂的PEDOT壳确保了复合材料中的高导电网络（100.6 S cm），并在单个复合单元的内表面和外表面提供了互穿的快速离子/电子传输途径。此外，内部的孔隙提供了空隙空间，以缓冲循环过程中纳米级框架的体积膨胀。特别是，有机-无机界面（PEDOT壳和FeO核之间）上Fe-S键的形成增强了结构稳定性，并进一步延长了电池的循环寿命。PEDOT-IE-FeO被用作锂离子电池阳极，表现出优异的锂存储能力和循环稳定性。在0.05 A g下容量高达1096 mA h g，倍率性能优异，在1000次循环（2 A g）后具有长而稳定的循环过程，容量保持率为89%（791 mA h g）。我们展示了一种新型的互穿封装结构，以高度增强金属氧化物纳米结构的电化学性能，特别是循环稳定性，并为设计电化学储能材料提供了新的见解。
