1 research outputs found
Designing Air-Stable O3-Type Cathode Materials by Combined Structure Modulation for Na-Ion Batteries
No full textAs promising high-capacity cathode materials for Na-ion batteries,
O3-type Na-based metal oxides always suffer from their poor air stability
originating from the spontaneous extraction of Na and oxidation of
transition metals when exposed to air. Herein, a combined structure
modulation is proposed to tackle concurrently the two handicaps via
reducing Na layers spacing and simultaneously increasing valence state
of transition metals. Guided by density functional theory calculations,
we demonstrate such a modulation can be subtly realized through cosubstitution
of one kind of heteroatom with comparable electronegativity and another
one with substantially different Fermi level, by adjusting the structure
of NaNi<sub>0.5</sub>Mn<sub>0.5</sub>O<sub>2</sub> via Cu/Ti codoping.
The as-obtained NaNi<sub>0.45</sub>Cu<sub>0.05</sub>Mn<sub>0.4</sub>Ti<sub>0.1</sub>O<sub>2</sub> exhibits an increase of 20 times in
stable air-exposure period and 9 times in capacity retention after
500 cycles, and even retains its structure and capacity after being
soaked in water. Such a simple and effective structure modulation
reveals a new avenue for high-performance O3-type cathodes and pushes
the large-scale industrialization of Na-ion batteries a decisive step
forward
