title: Exploring the possibilities of two-dimensional transition metal carbides as anode materials for sodium batteries.
abstract: Recently a group of two-dimensional materials called MXenes have been discovered and they have demonstrated their potential in Li rechargeable batteries. Herein, the Na storage and ion migration properties of M2C-type MXenes (M = Ti, V, Cr, Mn, Fe, Co, Ni, Nb, Mo) were investigated using density functional theory (DFT) calculations, and were compared to the Li case. Based on the average voltage and migration barrier of surface ions, we suggest that M = Ti, V, Cr, Mn, and Mo are suitable for sodium ion battery (SIB) anodes. These screened M2C materials can provide a theoretical capacity of 190-288 mA h g(-1) by accommodating two alkali ions per formula unit. They also exhibit an activation barrier of 0.1-0.2 eV for ionic motion, suggesting that the M2C materials are promising for high-power applications. The underlying aspects of the voltage differences between M2C materials are also discussed using electrostatic considerations.
authors.affiliation: Graduate School of Energy, Environment, Water and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, Republic of Korea. ysjn@kaist.ac.kr.
authors.forename: Eunjeong
authors.initials: E
authors.lastname: Yang
authors.forename: Hyunjun
authors.initials: H
authors.lastname: Ji
authors.forename: Jaehoon
authors.initials: J
authors.lastname: Kim
authors.forename: Heejin
authors.initials: H
authors.lastname: Kim
authors.forename: Yousung
authors.initials: Y
authors.lastname: Jung