Robust and Fast Lithium Storage Enabled by Polypyrrole-Coated Nitrogen and Phosphorus Co-Doped Hollow Carbon Nanospheres for Lithium-Ion Capacitors

• Published in: Frontiers in chemistry Vol. 9; p. 760473
• Main Authors: Zhang, Mengdi, Zheng, Xuan, Mu, Jiawei, Liu, Pengfei, Yuan, Wenhan, Li, Shuli, Wang, Xiaobo, Fang, Haiqiu, Liu, Haiyan, Xing, Tao, Hu, Han, Wu, Mingbo
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 24.09.2021
• Subjects: anode materials; Chemistry; conductive polymers; heteroatom doping; hollow structure; lithium-ion capacitors; porous carbon
• ISSN: 2296-2646; 2296-2646
• DOI: 10.3389/fchem.2021.760473

Lithium-ion capacitors (LICs) have been proposed as an emerging technological innovation that integrates the advantages of lithium-ion batteries and supercapacitors. However, the high-power output of LICs still suffers from intractable challenges due to the sluggish reaction kinetics of battery-type anodes. Herein, polypyrrole-coated nitrogen and phosphorus co-doped hollow carbon nanospheres (NPHCS@PPy) were synthesized by a facile method and employed as anode materials for LICs. The unique hybrid architecture composed of porous hollow carbon nanospheres and PPy coating layer can expedite the mass/charge transport and enhance the structural stability during repetitive lithiation/delithiation process. The N and P dual doping plays a significant role on expanding the carbon layer spacing, enhancing electrode wettability, and increasing active sites for pseudocapacitive reactions. Benefiting from these merits, the NPHCS@PPy composite exhibits excellent lithium-storage performances including high rate capability and good cycling stability. Furthermore, a novel LIC device based on the NPHCS@PPy anode and the nitrogen-doped porous carbon cathode delivers a high energy density of 149 Wh kg −1 and a high power density of 22,500 W kg −1 as well as decent cycling stability with a capacity retention rate of 92% after 7,500 cycles. This work offers an applicable and alternative way for the development of high-performance LICs.