Nanotechnology Now - Press Release: New fiber-shaped supercapacitor for wearable electronics

Recently, Prof. Huisheng Peng's group from Fudan University, China designed a novel family of amphiphilic core-sheath structured CNT composited fiber, i.e., CNT-polyaniline to meet the above requirements in Science China Materials (DOI: 10.1007/s40843-018-9408-3).

Prof. Peng stated: "The amphiphilic core-sheath structured CNT composited fiber can achieve more ion accessibility across the sheath originating from the enhanced interactions between OCNTs and PANI, and faster electron transport across the core attributing to the sufficient deposition of Au nanoparticles on the CNTs. This electrode design can improve both the electrical conductivity and electrochemical activity of one single fiber electrode."

They systematically studied the morphologies and electrochemical properties of electrodeposited PANI on the hydrophilic OCNT and hydrophobic CNT sheath. More oxygen-containing functional groups and defect sites on hydrophilic OCNT sheath are beneficial to the infiltration and electrodeposition of aniline in the aqueous electrolyte, improving the interactions between OCNTs and PANI than those between CNTs and PANI. As a result, PANI molecules are less aggregated with more accessibility to the ions in the electrolyte during charging and discharging processes, realizing a greater pseudocapacitance utilization. As to the Au-deposited CNT core, the homogeneous distribution of Au nanoparticles facilitates the electron transport among CNTs which finally reduces the internal resistance. Impressively, the demonstrates both high specific capacitance and rate capability, i.e., 256 F cm?3 at a high current density of 50 A cm?3 with a 79% retention of that at 0.5 A cm?3 (324 F cm?3). A remarkable energy density and power density of 7.2 mWh cm?3 and 10 W cm?3 are achieved in the resulting fiber-shaped supercapacitors, respectively.

"Our new concept, increasing the electron supply and ion accessibility simultaneously, can guide the future electrode design aiming at high performances," says Prof. Peng. "And the strategy of structure design and material utilization can be generalized to other energy storage systems including but not limited to lithium-ion and metal-air batteries. We believe this finding will be of interest to readers in energy science, materials chemistry and catalysis."

###

This work was supported by the Ministry of Science and Technology, the National Natural Science Foundation of China, Shanghai Science and Technology Committee, and Yanchang Petroleum Group.