Exploring new layer-structured cathode materials for sodium-ion batteries

 

Kyung-Wan Nam^a*

 

^aDepartment of Energy and Materials Engineering, Dongguk University, Seoul 04620 Republic of Korea

 

*Corresponding author e-mail address: knam@dongguk.edu

 

Abstract

 

Rechargeable sodium-ion batteries (SIBs) are now attracting special attention with a significant cost advantage over rechargeable lithium-ion batteries (LIBs), especially in the field of large-scale applications. For the successful development of the SIBs, it is imperative to find new cathode materials with high- voltage, capacity, power, and long cycle life. As an endeavor to find such electrode materials, we have explored new cathode materials based on layered-structure. We have investigated the O3-type layer structured oxides with a general formula of Na₃M(II)₂M(V)O6 having a honeycomb ordering of M(II) and M(V) in the metal layer. One of these class materials, Na₃Ni₂BiO₆, can reversibly deliver specific discharge capacities of up to 109 mAh/g with very flat- and high- voltage plateaus ~3.5V vs. Na/Na+. P2-type Mn-based oxide materials with a layered structure have also been explored as a high-capacity cathode by enabling the oxygen redox reaction. We also have investigated the charge storage mechanism of these new electrode materials by using various synchrotron-based x-ray characterization tools, including in situ x-ray diffraction and x-ray absorption spectroscopy. Detailed electrochemical results combined with structural characterization will be presented in the meeting.

 

 

Keywords: Sodium-ion batteries, Cathode material, Energy storage, Anionic redox, Density of states, Phase transition

 

References

[1] K.-W. Nam et al., “Honeycomb-layer structured Na₃Ni₂BiO₆ as a high voltage and long life cathode material for sodium-ion batteries”, Journal of Materials Chemistry A, Vol. 5 (2017) 1300-1310 pp.

[2] K.-W. Nam et al., “Unraveling vacancy-induced oxygen redox reaction and structural stability in Na-based layered oxides”, Chemical Engineering Journal, in press (2021)

 https://doi.org/10.1016/j.cej.2021.133962.