High-Voltage Layered NaNi0.5Co0.,Ti0.3Sb0.,O2 Cathode for Sodium-Ion Batteries

Developing a high-voltage cathode material for sodium-ion batteries is a great challenge. Herein, we report an O3 type layered NaNi0.5Co0.1Ti0.3Sb0.1O2 cathode composition, which can operate at a high voltage (4.35 V). Inclusion of different valence state transition metals, like Ni, Co, and Ti, and a metalloid Sb in the sodium metal oxide composition leads to the formation of a cationic disordered structure, which enhances redox, electronic conductivity, cycling stability, and working voltage. The structural characterizations reveal that the composition is free from superstructure reflections, and electrochemical studies show that the composition suppresses multiphase transitions. As a result, NaNi0.5Co0.1Ti0.3Sb0.1O2, exhibits initial charge and discharge capacities as 129 and 112 mAh/g, respectively, at the current rate of 9.1 mA/g for 2.0-4.35 V. Thus, the high voltage, improved capacity, and retention characteristics of NaNi0.5Co0.1Ti0.3Sb0.1O2 would open up the way for bulk production of Na-ion batteries.