Voltage hysteresis loop as a fingerprint of slow kinetics Co<sup>2+</sup>-to-Co<sup>3+</sup> transition in layered Na<sub><i>x</i></sub>Co<sub><i>x</i>/2</sub>Ti<sub>1−<i>x</i>/2</sub>O<sub>2</sub> cathodes for sodium batteries
Journal of materials chemistry. A