Titanium-based polyanionic phosphate should theoretically be a promising electrode material for Na-ion batteries(NIBs) due to its low cost, robust structure framework and high safety. However, the currently reported titanium-based materials either have low reversible capacity or low average voltage, which makes them unable to serve as a cathode for practical NIBs due to undesirable energy density. Herein, by combining the inductive effect of Fanions with strong electronegativity and the KTiOPO4 (KTP)-type framework, we develop a novel titanium-based NaTiPO4F material, which demonstrates a reversible capacity of ~137 mA h g-1 and energy density of ~355 W h kg-1 for NIBs. Various in situ characterizations combined with theoretical calculations have

revealed favorable Na+ ion diffusion kinetics, reversible Ti3+/Ti4+ redox and quasi solid solution reaction mechanisms in NaTiPO4F electrodes. Our current work shed light on the design and application of low-cost titanium-based phosphate electrodes for high-performance NIBs.