Cobalt disulfide/carbon nanofibers with mesoporous heterostructure and excellent hydrophilicity for high energy density asymmetric supercapacitor

作者：Wenjie Liu, Fen Qiao, Jing Yang, Jiaren Yuan, Yi Xie, Tao Wang, Jinzhi Hu, Jihua Zheng, Rui Ren, Xiao‐Min Kang, Yan Zhao, Jiangwei Zhang · 发表于：Nano Research · 年份：2023 · DOI：10.1007/s12274-023-5533-1 · 被引用次数：43 · 研究领域：Supercapacitor Materials and Fabrication、Advancements in Battery Materials、Advanced battery technologies research

Herein, a unique mesoporous heterostructure (average pore size: 15 nm) cobalt disulfide/carbon nanofibers (CoS 2 /PCNFs) composite with excellent hydrophilicity (contact angle: 23.5°) is prepared using polyethylene glycol (PEG) as a pore-forming agent. The CoS 2 /PCNF electrode exhibits excellent cycle stability (95.2% of initial specific capacitance at 10 A·g −1 after 8000 cycles), good rate performance (46.5% at 10 A·g −1 ), and high specific capacity (86.1 mAh·g −1 at 1 A·g −1 , about 688.8 F·g −1 at 1 A·g −1 ). Density functional theory (DFT) simulation elucidates that CoS 2 tends to transfer substantial charges to CNF. As the center of positive charge, CoS 2 is more likely to capture negative ions in the electrolyte, thus accelerating the ion diffusion process. The excellent properties of the electrode material can not only accelerate the electrochemical reaction kinetics, but also provide abundant redox-active sites and a high Faradaic capacity for the entire electrode due to the synergistic contributions of CoS 2 nanoparticles, mesoporous heterostructure of PCNF, and admirable hydrophilicity of the composite material. A CoS 2 /PCNF-0.25//AC (AC: activated carbon) asymmetric supercapacitor is assembled using CoS 2 /PCNF-0.25 as the positive electrode and AC as the negative electrode, which possesses a high energy density (35.5 Wh·kg −1 at a power density of 824 W·kg −1 ) and superior cycling stability (maintaining over 98% of initial capacitance after 2000 cycles). In a...