Layered P2-Na_2/3Co_1/2Ti_1/2O₂ as a high-performance cathode material for sodium-ion batteries

Noha Sabi (1, 2) , Siham Doubaji (1) , Kasuki Hashimoto (3) , Shinichi Komaba (3) , Khalil Amine (4) , Abderrahim Solhy (2) , Bouchaib Manoun (2, 5) , Essaïd Bilal (6, 7, 8, 9) , Ismael Saadoune (1, 2)

1 LCME - Département de Chimie
2 Materials Science and Nano-engineering Department
3 Department of Applied Chemistry
4 Chemical Sciences and Engineering
5 Laboratoire des Sciences des Matériaux, des Milieux et de la modélisation
6 Groupe OCP
7 SPIN-ENSMSE - Centre Sciences des Processus Industriels et Naturels
8 EVS - Environnement, Ville, Société
9 PEG-ENSMSE - Département Procédés pour l'Environnement et Géoressources

Layered oxides are regarded as promising cathode materials for sodium-ion batteries. We present Na_2/3Co_1/2Ti_1/2O₂ as a potential new cathode material for sodium-ion batteries. The crystal features and morphology of the pristine powder were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The cathode material is evaluated in galvanostatic charge-discharge and galvanostatic intermittent titration tests, as well as ex-situ X-ray diffraction analysis. Synthesized by a high-temperature solid state reaction, Na_2/3Co_1/2Ti_1/2O₂crystallizes in P2-type structure with P6_3/mmc space group. The material presents reversible electrochemical behavior and delivers a specific discharge capacity of 100 mAh g⁻¹ when tested in Na half cells between 2.0 and 4.2 V (vs. Na⁺/Na), with capacity retention of 98% after 50 cycles. Furthermore, the electrochemical cycling of this titanium-containing material evidenced a reduction of the potential jumps recorded in the Na_xCoO₂ parent phase, revealing a positive impact of Ti substitution for Co. The ex-situ XRD measurements confirmed the reversibility and stability of the material. No structural changes were observed in the XRD patterns, and the P2-type structure was stable during the charge/discharge process between 2.0 and 4.2 V vs. Na⁺/Na. These outcomes will contribute to the progress of developing low cost electrode materials for sodium-ion batteries.

Mots clés: P2 structure; Energy storage; Na-ion batteries; Na_2/3Co_1/2Ti_1/2O₂; Cathode material

Domaines: Génie des procédés

Noha Sabi, Siham Doubaji, Kasuki Hashimoto, Shinichi Komaba, Khalil Amine, et al.. Layered P2-Na_2/3Co_1/2Ti_1/2O₂ as a high-performance cathode material for sodium-ion batteries. Journal of Power Sources, 2017, 342, pp.998-1005. ⟨10.1016/j.jpowsour.2017.01.025⟩. ⟨hal-01490456⟩