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Effect of Vapor Carbon Coating on the Surface Structure and Sodium Storage Performance of Hard Carbon Spheres
Author(s) -
Zhang Yuqi,
Zhang Nan,
Chen Weilun,
Rao Zhixiang,
Wu Jiajie,
Xue Lihong,
Zhang Wuxing
Publication year - 2019
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201900779
Subject(s) - carbon fibers , materials science , chemical engineering , coating , anode , pyrolysis , faraday efficiency , sodium , plateau (mathematics) , layer (electronics) , composite material , nanotechnology , chemistry , composite number , electrode , metallurgy , mathematical analysis , mathematics , engineering
Hard carbons have received considerable attention as anode materials for sodium‐ion batteries (SIBs). However, it is still a challenge to improve the plateau capacity and initial coulombic efficiency (ICE) of hard carbons. Herein, a facile vapor carbon‐coating method is used to modify the surface structure of carbon spheres (CS) via the pyrolysis of polypropylene (PP), aiming to seal the exposed pores through a high‐quality carbon layer. CS@2%PP exhibits highly improved sodium storage performance compared to that of the pristine CS, which delivers a plateau capacity of 220 m Ah g −1 and an ICE of 81%. Further investigations show that the improved sodium storage performance of CS@2%PP can be mainly attributed to the reduced structural defects on the surface, lower specific surface area (11.5 m 2 g −1 ), and increased closed pores (12.5%) via carbon coating. The results prove that the surface vapor carbon coating is a facile route to improve the plateau capacity and ICE of hard carbon anodes in SIBs.