Programme

P.57 -- Poster, NCTP-43

Date: Wednesday, 1 August 2018

Time: 08:30 - 10:00

Investigating the diffusion processes of Na ions in cathode material Na2Mn3(SO4)4 by using density functional theory

Thien Lan Tran1, Nhu Thao Dinh1 and Van An Dinh2

1Hue University of Education, 34 Le Loi Str., Hue, Vietnam. 2Nanotechnology Program, Vietnam Japan University (VNU), Luu Huu Phuoc Str., My Dinh I, Hanoi, Vietnam.

Rechargeable Sodium-ion battery has attracted many scientists in the field of energy storage because it can be expected as an alternative one for Lithium-ion batteries. For the cathode materials of sodium-ion batteries, Na2M3(SO4)4 (M: a transition metal) is one of promising materials. Although the predictions for diffusion processes of Na ions have been made using the concept of bond valence sum based on X-ray diffraction data on crystals [1], the detail of diffusion mechanism has not still been fully explored yet. In 2012, V. A. Dinh et al. proposed a new insight in describing the diffusion of Li/Na ion with accompanied by a quasi-particle so called small polaron to explore the diffusion inside cathode materials [2-4]. For Na2M3(SO4)4, the removal or insertion of Na ion would lead to the formation of a bound polaron at the transition metal site. Consequently, the diffusion of the charge carriers in this material would be accompanied by the polaron migration. In this talk, we present the DFT calculation of crystal and electronic structures of Na2Mn3(SO4)4. The diffusion process of Na ion in this material will be illustrated through the elementary diffusion processes (EDPs) of Na vacancy and accompanying polaron. The diffusion pathways are explored and activation barrier will be evaluated via combination of EDPs.

Presenter: Tran Thien Lan