ZnO-assisted synthesis of lignin-based ultra-fine microporous carbon nanofibers for supercapacitors

Chang Ma; Liqiang Wu; Mahmut Dirican; Hui Cheng; Junjing Li; Yan Song; Jingli Shi; Xiangwu Zhang

doi:10.1016/j.jcis.2020.10.105

ZnO-assisted synthesis of lignin-based ultra-fine microporous carbon nanofibers for supercapacitors

J Colloid Interface Sci. 2021 Mar 15:586:412-422. doi: 10.1016/j.jcis.2020.10.105. Epub 2020 Oct 27.

Authors

Chang Ma¹, Liqiang Wu², Mahmut Dirican³, Hui Cheng³, Junjing Li², Yan Song⁴, Jingli Shi², Xiangwu Zhang⁵

Affiliations

¹ Tianjin Municipal Key Lab of Advanced Fiber and Energy Storage Technology, Tiangong University, Tianjin 300387, China; Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, Wilson College of Textiles, North Carolina State University, Raleigh, NC 27695-8301, United States. Electronic address: machang@tiangong.edu.cn.
² Tianjin Municipal Key Lab of Advanced Fiber and Energy Storage Technology, Tiangong University, Tianjin 300387, China.
³ Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, Wilson College of Textiles, North Carolina State University, Raleigh, NC 27695-8301, United States.
⁴ CAS Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, 030001, China.
⁵ Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, Wilson College of Textiles, North Carolina State University, Raleigh, NC 27695-8301, United States. Electronic address: xiangwu_zhang@ncsu.edu.

PMID: 33189324
DOI: 10.1016/j.jcis.2020.10.105

Abstract

Reducing the material size could be an effective approach to enhance the electrochemical performance of porous carbons for supercapacitors. In this work, ultra-fine porous carbon nanofibers are prepared by electrospinning using lignin/ polyvinylpyrrolidone as carbon precursor and zinc nitrate hexahydrate (ZNH) as an additive, followed by pre-oxidation, carbonization, and pickling processes. Assisted by the ZnO template, the pyrolytic product of ZNH, abundant micropores are yielded, leading to the formation of microporous carbon nanofibers with specific surface area (SSA) up to 1363 m² g^-1. The average diameter of the lignin-based ultra-fine porous carbon nanofibers (LUPCFs) is effectively controlled from 209 to 83 nm through adjusting the ZNH content. With good flexibility and self-standing nature, the LUPCFs could be directly cut into electrodes for use in supercapacitors. High accessible surface, enriched surface N/O groups, and reduced fiber diameters endow the LUPCFs-based electrodes with an excellent specific capacitance of 289 F g^-1. The reduction of fiber diameters remarkably improves the rate performance of the LUPCFs and leads to a low relaxation time constant of 0.37 s. The high specific capacitance of 162 F g^-1 is maintained when the current density is increased from 0.1 to 20 A g^-1. Besides, the fabricated LUPCFs show exceptional cycling stability in symmetrical supercapacitors, manifesting a promising application prospect in the next generation of supercapacitors.

Keywords: Carbon nanofibers; Lignin; Microporous carbons; Supercapacitors; Ultra-fine.