Hybrid Functional Study on Small Polaron Formation and Ion Diffusion in the Cathode Material Na2Mn3(SO4)4

Thien Lan Tran; Huu Duc Luong; Diem My Duong; Nhu Thao Dinh; Van An Dinh

doi:10.1021/acsomega.0c00009

Hybrid Functional Study on Small Polaron Formation and Ion Diffusion in the Cathode Material Na₂Mn₃(SO₄)₄

ACS Omega. 2020 Mar 5;5(10):5429-5435. doi: 10.1021/acsomega.0c00009. eCollection 2020 Mar 17.

Authors

Thien Lan Tran^{1

2}, Huu Duc Luong^{1

3

4}, Diem My Duong⁵, Nhu Thao Dinh², Van An Dinh¹

Affiliations

¹ Nanotechnology Program, VNU Vietnam Japan University, Luu Huu Phuoc Street, My Dinh I, Nam Tu Liem, Hanoi 10000, Vietnam.
² Department of Physics, Hue University of Education, Hue University, 34 Le Loi Street, Hue 49000, Vietnam.
³ Division of Precision Science & Technology and Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
⁴ Department of Theoretical Nanotechnology, The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
⁵ Center of Theoretical and Computational Physics, Hue University of Education, Hue University, 34 Le Loi Street, Hue 49000, Vietnam.

Abstract

The crystal structure, electronic structure, and diffusion mechanism of Na ions in the cathode material Na₂Mn₃(SO₄)₄ are investigated based on the Heyd-Scuseria-Ernzerhof hybrid density functional method. The simultaneous motion model of polaron-sodium vacancy complexes was used to reveal the diffusion mechanism of Na ions in this material. Polaron formation at the Mn third-nearest neighbor to the Na vacancy was found. Two crossing and two parallel elementary diffusion processes of the polaron-Na vacancy complex were explored. The most preferable elementary diffusion process has an activation energy of 852 meV, which generates a zigzag-like pathway of Na-ion diffusion along the [001] direction in the whole material. Possessing a voltage of 4.4 V and an activation energy of 852 meV, Na₂Mn₃(SO₄)₄ is expected to be a good cathode material for rechargeable sodium ions.