Electrospun Na3MnTi(PO4)3/C film: A multielectron-reaction and free-standing cathode for sodium-ion batteries

[Display omitted] •Firming free-standing structure to enhance long-term durability and cyclic stability.•Optimizing electronic conductivity to achieve outstanding rate capability.•Reversible multi-electron reaction enabling high specific capacity. With the continuous advancement of renewable energy sources, sodium-ion batteries are currently regarded as highly promising technologies for large-scale electric energy storage. The compound Na3MnTi(PO4)3 has garnered significant attention owing to its exceptional theoretical capacity, robust structural stability, and abundant availability of resources. Herein, hierarchical carbon-decorated Na3MnTi(PO4)3 nanofibers are synthesized via a feasible electrospinning technique followed by pyrolysis, effectively addressing the issue of poor electronic conductivity in phosphate cathodes. The free-standing Na3MnTi(PO4)3/C electrode serves as a cathode for sodium-ion batteries, exhibiting exceptional electronic conductivity and superior Na+ transport capability. Moreover, it demonstrates an impressive reversible capacity of 171.4 mA h g−1 at 0.2C and exhibits outstanding cyclic stability with a capacity retention of 63.7 % after 6300 cycles at 1C. The full cell, assembled with independent Na3MnTi(PO4)3/C cathode and hard carbon anode, exhibits a reversible capacity of 153.7 mA h g−1 at a current density of 10 mA g−1. The in-situ synthesis of nanomaterial particles within interconnected porous nanocarbon fibers can effectively enhance the materials' poor electronic conductivity, thereby further improving their cyclic stability and Na+ transport kinetics.