Affiliation:
1. State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Dingxi Road Changning District Shanghai 200050 P. R. China
2. Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular Engineering Peking University 292 Chengfu Road Haidian District Beijing 100871 P. R. China
Abstract
AbstractHard carbon (HC) anode shows great potential due to its high capacity and excellent rate performance. However, state‐of‐the‐art HC anode still suffers insufficient initial Coulomb efficiency (ICE) due to the abundant Li‐trapping sites. Herein, we demonstrate a facile annealing engineering for HC anodes to improve the ICE and the mechanism is systematically studied. Accordingly, during the annealing process, metastable O‐ and N‐containing functional groups are pyrolyzed, which cause the microstructure reconstruction of HC. Therefore, irreversible lithium ions adsorption is reduced significantly and the conversion of sp3 to sp2 C contributes to the localized graphitization of HC. Consequently, the optimized HC achieves ultra‐high ICE of 90% from initial 61%. It is demonstrated that HC will adsorb H2O and some organic species from environment gradually, causing conversion of some electrochemical stable functional groups to the irreversible Li‐trapping sites. This work provides facile strategy and novel insight for high ICE HC anodes.
Funder
National Natural Science Foundation of China
Science and Technology Commission of Shanghai Municipality
Subject
General Chemistry,Biochemistry,Organic Chemistry
Cited by
2 articles.
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