title: Li2C2, a High-Capacity Cathode Material for Lithium Ion Batteries.
abstract: As a typical alkaline earth metal carbide, lithium carbide (Li2C2) has the highest theoretical specific capacity (1400 mA h g(-1)) among all the reported lithium-containing cathode materials for lithium ion batteries. Herein, the feasibility of using Li2C2 as a cathode material was studied. The results show that at least half of the lithium can be extracted from Li2C2 and the reversible specific capacity reaches 700 mA h g(-1). The C≡C bond tends to rotate to form C4 (C≡C⋅⋅⋅C≡C) chains during lithium extraction, as indicated with the first-principles molecular dynamics (FPMD) simulation. The low electronic and ionic conductivity are believed to be responsible for the potential gap between charge and discharge, as is supported with density functional theory (DFT) calculations and Arrhenius fitting results. These findings illustrate the feasibility to use the alkali and alkaline earth metal carbides as high-capacity electrode materials for secondary batteries.
authors.affiliation: Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condense Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603, Beijing 100190 (China).
authors.forename: Na
authors.initials: N
authors.lastname: Tian
authors.affiliation: Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condense Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603, Beijing 100190 (China).
authors.forename: Yurui
authors.initials: Y
authors.lastname: Gao
authors.affiliation: College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing University of Technology, Beijing 100124 (China).
authors.forename: Yurong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condense Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603, Beijing 100190 (China). zxwang@iphy.ac.cn.
authors.forename: Zhaoxiang
authors.initials: Z
authors.lastname: Wang
authors.affiliation: College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing University of Technology, Beijing 100124 (China).
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Song
authors.affiliation: Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condense Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603, Beijing 100190 (China).
authors.forename: Liquan
authors.initials: L
authors.lastname: Chen
keywords: Li2C2; density functional theory; high capacity; lithium ion battery