High-sulfur-doped hard carbon for sodium-ion battery anodes with large capacity and high initial coulombic efficiency
SUSTAINABLE ENERGY & FUELS(2022)
摘要
As one of the most promising potential anodes for sodium ion batteries, hard carbon suffers from low specific capacity, which seriously hinders its further application. In the present work, a novel S-doped hard carbon material (SHC) with an ultrahigh S content of 15.91% is designed by a simple sulfonation treatment of terthiophene. Ex situ X-ray Photoelectron Spectroscopy, X-ray Diffractometer and Transmission Electron Microscope results demonstrate that the S atoms supply redox reaction sites with Na+ and lead to the formation of NaxS, thus endowing the SHC with superior Na storage performance. The SHC has a large reversible capacity of 777 mA h g(-1), and it shows good cycling stability that a high capacity of 758 mA h g(-1) is maintained after 1000 cycles, with no dramatic capacity loss. Meanwhile, it is notable that SHC-500 has a surprisingly high initial coulombic efficiency (ICE) of 84.4%, demonstrating good potential in practical use. Kinetics analysis reveals that the S atoms store Na through a dominant fast surface reaction, and then the SHC has good high-rate performance, e.g., a capacity of 353 mA h g(-1) is delivered at a large current density of 10 A g(-1).
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关键词
hard carbon,high-sulfur-doped initial coulombic efficiency,sodium-ion
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