Sodium-deficient O3–Na0.9Mn0.4Fe0.5Ti0.1O2 as a cathode material for sodium-ion batteries

A novel sodium-deficient material O3-type Na0.9Mn0.4Fe0.5Ti0.1O2 has been successfully synthesized for the first time by molten salt method. This material delivers a reversible capacity of about 109 mA h g−1 at 0.1C, and excellent cycling performance with capacity retention of 102 mA h g−1 after 150 cycles. In addition, the NMFTO also demonstrates a good rate capability at various current densities from 0.1C to 5C. Even after a long cycling life up to 400 cycles, the reversible capacity remains as high as 60 mA h g−1 at 5C.