Environmentally friendly, inexpensive iron-titanium tunneled oxide anodes for Na-ion batteries. (15th January 2022)

• Record Type: Journal Article
• Authors: Nowak, Mikołaj; Zając, Wojciech; Molenda, Janina
• Is Part Of: Energy. Volume 239:Part E(2022)
• Publication Date: 2022-01-15
• Subjects: Na-ion batteries -- Oxide anode materials -- Iron-based oxides -- Tunneled structure -- NaFeTiO4; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2021.122388
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: Within this paper, we investigate the electrochemical performance of NaFeTiO4, Na0.9 Fe0.9 Ti1.1 O4, Na0.8 Fe0.8 Ti1.2 O4 tunneled structured anodes for Na-ion batteries. Sol-gel synthesis enables to obtain anode materials characterized by improved morphology leading to enhanced electrochemical behavior in Na-ion batteries. Impedance spectroscopy and UV-VIS measurements reveal that electronic component dominates in total electrical conductivity, which is one order of magnitude higher for Na0.9 Fe0.9 Ti1.1 O4, Na0.8 Fe0.8 Ti1.2 O4 in comparison to NaFeTiO4 . Among the studied materials, Na0.8 Fe0.8 Ti1.2 O4 possesses the highest charge capacity of 180 mAh g −1 during the first cycle at C/20 and can retain 80% of the initial capacity after 30 cycles with an average charging voltage of 1.3 V vs. Na + /Na. Experiments in temperatures from −20 °C to +60 °C reveal that Na0.8 Fe0.8 Ti1.2 O4 preserve a significant fraction of its capacity: 70 mAh g −1 at −20 °C and 177 mAh g −1 at 60 °C. Application of ether-based diglyme solvents instead of ester-based results in reduced irreversible reactions during the initial discharge-charge cycle, better performance under higher loads, and lower charge transfer and SEI resistance. The results prove that Na0.8 Fe0.8 Ti1.2 O4 is an auspicious material for future low-cost Na-ion batteries with stable performance in a wide temperature range. Graphical abstract: Image 1 Highlights: Fe and Ti-based oxides with tunnel structure were synthesized via sol-gel method. Electrical and optical properties were linked to performance in Na-ion cells. Diglyme-based solvents improved coulombic efficiency and rate capability. Double-tunneled Nax Fex Ti2-x O4 anodes retain 70% of nominal capacity in −20 °C.