NaTiO2: a layered anode material for sodium-ion batteries

We report on layered NaTiO2 as a potential anode material for Na-ion batteries. The material is prepared from only earth-abundant elements, delivers 152 mA h g(-1) of reversible capacity at C/10 rate, shows excellent cyclability with capacity retention over 98% after 60 cycles, and high rate capability. Furthermore, in situ X-ray diffraction analysis reveals a reversible O3-O'3 phase transition, including an unusual lattice parameter variation coupled to complicated Na vacancy orderings in a series of 2nd order phase transitions.