Recently, sodium-ion batteries (SIB) have been considered a promising alternative to lithium-ion batteries due to the abundance of sodium resources (sodium is the Earth’s 6^th most abundant element, while lithium is 33^rd) and its low extraction costs. Among various cathode candidates, the layered oxides NaT_MO₂ (T_M=3d transition metal elements and their mixture) can accommodate sodium ions through intercalation mechanism, but suffer from major limitations including poor rate capability and short cycle-life. We have developed a novel bulk Na_2/3[Ni_1/3Mn_2/3]O₂ structure containing inclusions, which exhibits an unprecedented rate capability with roughly 50 % capacity retention at 50 C, and a remarkable long-term cycling stability with 95% capacity retention after 1000 cycles at 5 C. During this talk, I will present our new results and elucidate the mechanism through which the cycling performance of the novel materials system is enhanced.

References

1. Ruiz, M. Cochrane, M. Li, Y. Yan, K. Ma, J. Fu, Z. Wang, SH. Tolbert, VB. Shenoy, E. Detsi, Adv. Energy. Mater., 8 (2018) 1801781.
2. Li, Z. Wang, J. Fu, K. Ma, E. Detsi, Scripta Materialia, 164 (2019) 52-56.