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CoS2 Nanoparticles Wrapping on Flexible Freestanding Multichannel Carbon Nanofibers with High Performance for Na-Ion Batteries

Pan, Yuelei, Cheng, Xudong, Huang, Yajun, Gong, Lunlun, Zhang, Heping
ACS applied materials & interfaces 2017 v.9 no.41 pp. 35820-35828
batteries, carbon nanofibers, electrodes, electron transfer, energy, nanoparticles, sodium, sulfides
Exploration for stable and high-powered electrode materials is significant due to the growing demand for energy storage and also challengeable to the development and application of Na-ion batteries (NIBs). Among all promising electrode materials for NIBs, transition-mental sulfides have been identified as potential candidates owing to their distinct physics–chemistry characteristics. In this work, CoS₂ nanomaterials anchored into multichannel carbon nanofibers (MCNFs), synthesized via a facile solvothermal method with a sulfidation process, are studied as flexible free-standing electrode materials for NIBs. CoS₂ nanoparticles uniformly distributed in the vertical and horizontal multichannel networks. Such nanoarchitecture can not only support space for volume expansion of CoS₂ during discharge/charge process, but also facilitate ion/electron transport along the interfaces. In particular, the CoS₂@MCNF electrode delivers an impressively high specific capacity (537.5 mAh g–¹ at 0.1 A g–¹), extraordinarily long-term cycling stability (315.7 mAh g–¹ at at 1 A g–¹ after 1000 cycles), and excellent rate capacity (537.5 mAh g–¹ at 0.1 A g–¹ and 201.9 mAh g–¹ at 10 A g–¹) for sodium storage. Free-standing CoS₂@MCNF composites with mechanical flexibility provide a promising electrode material for high-powered NIBs and flexible cells.