Li Yuquan, Ni Bin, Li Xiaodan, Wang Xianghui, Zhang Dafeng, Zhao Qingfei, Li Jinliang, Lu Ting, Mai Wenjie, Pan Likun
Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, 3663 N. Zhongshan Rd., Shanghai, 200062, People's Republic of China.
Siyuan Laboratory, Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials, Department of Physics, Jinan University, Guangzhou, 510632, Guangdong, People's Republic of China.
Nanomicro Lett. 2019 Jul 17;11(1):60. doi: 10.1007/s40820-019-0291-z.
Na-ion batteries (NIBs) have attracted considerable attention in recent years owing to the high abundance and low cost of Na. It is well known that S doping can improve the electrochemical performance of carbon materials for NIBs. However, the current methods for S doping in carbons normally involve toxic precursors or rigorous conditions. In this work, we report a creative and facile strategy for preparing S-doped porous carbons (SCs) via the pyrolysis of conjugated microporous polymers (CMPs). Briefly, thiophene-based CMPs served as the precursors and doping sources simultaneously. Simple direct carbonization of CMPs produced S-doped carbon materials with highly porous structures. When used as an anode for NIBs, the SCs exhibited a high reversible capacity of 440 mAh g at 50 mA g after 100 cycles, superior rate capability, and excellent cycling stability (297 mAh g after 1000 cycles at 500 mA g), outperforming most S-doped carbon materials reported thus far. The excellent performance of the SCs is attributed to the expanded lattice distance after S doping. Furthermore, we employed ex situ X-ray photoelectron spectroscopy to investigate the electrochemical reaction mechanism of the SCs during sodiation-desodiation, which can highlight the role of doped S for Na-ion storage.
近年来，钠离子电池（NIBs）因其钠资源丰富且成本低廉而备受关注。众所周知，硫（S）掺杂可以改善用于钠离子电池的碳材料的电化学性能。然而，目前在碳材料中进行硫掺杂的方法通常涉及有毒前驱体或苛刻的条件。在这项工作中，我们报道了一种通过共轭微孔聚合物（CMPs）热解制备硫掺杂多孔碳（SCs）的创新且简便的策略。简而言之，基于噻吩的CMPs同时作为前驱体和掺杂源。CMPs简单的直接碳化产生了具有高度多孔结构的硫掺杂碳材料。当用作钠离子电池的阳极时，SCs在100次循环后，在50 mA g的电流密度下表现出440 mAh g的高可逆容量、优异的倍率性能和出色的循环稳定性（在500 mA g的电流密度下1000次循环后为297 mAh g），优于迄今为止报道的大多数硫掺杂碳材料。SCs的优异性能归因于硫掺杂后晶格间距的扩大。此外，我们采用非原位X射线光电子能谱研究了SCs在脱钠-嵌钠过程中的电化学反应机理，这可以突出掺杂硫在钠离子存储中的作用。
