期刊
ACS APPLIED MATERIALS & INTERFACES
卷 11, 期 19, 页码 17425-17434出版社
AMER CHEMICAL SOC
DOI: 10.1021/acsami.9b03077
关键词
Na/K-ion batteries; first-principles calculations; FeF3(012) nanosheet; cycling life; rate performance
资金
- National Natural Science Foundation of China [21573187]
- Hunan Provincial Natural Science Foundation of China [2017D2246]
- Opening Foundation of Key Laboratory of Materials Design and Preparation Technology of Hunan Province [KF20140701]
- Shenzhen Fundamental Research Foundation [JCYJ20170817105007999]
- Center for Computational Science and Engineering of Southern University of Science and Technology
Developing highly efficient FeF3-based cathode materials for Na/K-ion batteries is greatly needed, which needs long cycling life and rate performance besides large voltage and capacity. Accordingly, we designed a two-dimensional (2D) FeF3 nanosheet to obtain highly efficient Na/K-ion batteries. Moreover, first-principles calculations were implemented to discuss systematically the Na and K storage mechanism on the FeF3(012) nanosheet. The adsorption energies of Na and K are -3.55 and -3.98 eV, respectively, which can guarantee the Na/K loading process. Interestingly, Na and K adatoms on FeF3(012) prefer to get together in the form of the Na dimer and K tetramer, respectively. Energy barrier of the K tetramer is lower than that of the Na dimer (0.43 eV vs 0.45 eV). As a result, the K tetramer possesses a larger diffusion coefficient than the Na dimer (4.22 x 10(-1) cm(2).s(-1) vs 3.32 x 10(-10) cm(2).s(-1)) That is to say, good Na/K-ion mobility can be achieved. Also, the FeF3(012) nanosheet exhibits high initial discharge voltage (4.10 V for K and 3.74 V for Na). Moreover, it has a stable discharge voltage curve in Na/K-ion batteries. Besides, the FeF3(012) nanosheet is more favorable to be fabricated as a flexible cathode material for potassium batteries. Therefore, the 2D FeF3 nanosheet belongs to a promising cathode material in Na/K-ion batteries.
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