Tunnel-structured Na0.54Mn0.50Ti0.51O2 and Na0.54Mn0.50Ti0.51O2/C nanorods as advanced cathode materials for sodium-ion batteries

Tunnel-structured Na0.54Mn0.50Ti0.51O2 nanorods have been synthesized by a facile molten salt method. These nanorods are grown in the direction normal to the sodium-ion tunnels, greatly shortening the diffusion distance of sodium ions and benefiting the transfer kinetics. Thus, the nanorods show significant enhancements in terms of reversible capacity, cycling stability and rate capability. The electrochemical performance could be further promoted via carbon coating to similar to 122 mA h g(-1) after 150 cycles at 0.2 C or similar to 85 mA h g(-1) after 400 cycles at 1 C.