Interface and Doping Effect on the Electrochemical Property of Graphene/LiFePO4

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• 作者：Huayu Wang ; Naiqin Zhao ; Chunsheng Shi ; Chunnian He ; Jiajun Li ; Enzuo Liu
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：August 11, 2016
• 年：2016
• 卷：120
• 期：31
• 页码：17165-17174
• 全文大小：624K
• 年卷期：0
• ISSN：1932-7455

文摘

Surface properties of olivine phosphate LiFePO₄, as cathodes in lithium ion batteries, are of importance for overall performance as the nanoscale of particles has become indispensable. Using the first-principles total energy calculations, the effects of graphene or Mn dopant on the electrochemical properties of graphene/LiFePO₄ have been comprehensively investigated. It is revealed that the interfacial binding between graphene and LiFePO₄ in parallel orientation is stable and improved in the process of doping. The Li adsorption energy at different sites elucidates the core–shell model in Li extraction/insertion process and indicates the anomalous Li storage in the interface between graphene and LiFePO₄. Mechanisms underlying influences of adsorption site, Mn dopant, and graphene modification on the Li adsorption energy are discussed through edge effect, doping stability, and interfacial binding strength, respectively. The surface conductivity is improved in the presence of graphene or Mn dopant with respect to the bandlike electron transport.