摘要
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?1 at 50 mA g?1 after 100 cycles,superior rate capability,and excellent cycling stability(297 mAh g?1 after 1000 cycles at 500 mA g?1),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.
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-1 at 50 mA g-1 after 100 cycles, superior rate capability, and excellent cycling stability(297 mAh g-1 after 1000 cycles at 500 mA g-1), 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.
基金
Financial support from National Natural Science Foundation of China(Nos.51702056 and 51772135)
the Ministry of Education of China(6141A02022516)
China Postdoctoral Science Foundation(2017M622902 and 2019T120790).
