Integration of flexibility, cyclability and high-capacity into one electrode for sodium-ion hybrid capacitors with low self-discharge rate

• Main Authors: Wang, Huanwen, Xu, Dongming, Jia, Guichong, Mao, Zhifei, Gong, Yansheng, He, Beibei, Wang, Rui, Fan, Hong Jin
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2020
• Subjects: Engineering::Materials; Science::Chemistry; Flexible Energy Storage; Mesoporous Carbon Fiber
• Online Access: https://hdl.handle.net/10356/138102
• Institution: Nanyang Technological University

Metal-ion hybrid capacitors are regarded as promising power sources for portable electronics because of numerous opportunities in designing the anode/cathode couple to realize high performance and device flexibility. Here we demonstrate our rational design of a porous-fiber network based electrode for quasi-solid-state flexible Na-ion hybrid capacitors. A SiO2-etching approach is deployed to synthesize the freestanding porous carbon nanofiber (PCNF) membrane that is both mechanically robust and light (~1 mg cm−2). The PCNF serves as a 3D scaffold for the uniform growth of MoS2@poly(3,4-ethylenedioxythiophene) (PEDOT) core/shell nanosheets. The resultant PCNF@MoS2@PEDOT double core/shell nanofiber electrode not only maintains the intrinsic high-capacity of MoS2 for Na-ion storage, but also renders long-term cyclability and high rate performance. The constructed quasi-solid-state Na-ion hybrid capacitors can tolerate arbitrary bending and folding, and has a much lower self-discharge rate (15 mV h-1) compared to symmetric capacitors.