An interconnected NaTi2(PO4)3/carbon composite from an all-integrated framework with chelating Ti in a cross-linked citric acid-organic phosphonic acid skeleton for high-performance sodium storage.

[Display omitted] • NaTi 2 (PO 4) 3 /carbon is rationally designed from an all-integrated framework precursor. • Precursor is a citric acid-organic phosphonic acid skeleton chelating with Ti. • NaTi 2 (PO 4) 3 /carbon shows high capacity and superior rate capability for SIBs. • NaTi 2 (PO 4) 3 /carbon delivers an ultrastable cycling performance. Finding suitable hosts for Na+ ion storage holds the key to achieving large-scale applications of sodium-ion batteries (SIBs). NaTi 2 (PO 4) 3 is widely considered to be an advanced anode material for SIBs, because of its 3D open framework, high theoretical capacity, and good thermodynamic stability. However, the instability of electrolyte/electrode interface and intrinsic low electronic conductivity of NaTi 2 (PO 4) 3 lead to the poor cycling and rate performance. In this work, an all-integrated framework with chelating Ti in a cross-linked citric acid-organic phosphonic acid skeleton is fabricated as a precursor for the synthesis of NaTi 2 (PO 4) 3 /carbon composite. The generated interconnected carbon provides extensive support for NaTi 2 (PO 4) 3 crystal. These unique structure delivers a high reversible capacity (225.8 mAh g−1 at 0.2 A g−1), good rate performance (219.7 mAh g−1 at 0.4 A g−1, and 189.6 mAh g−1 at 1 A g−1), and superb long-term cycling stability (156.0 mAh g−1 at 2 A g−1 after 4000 cycles). It is believed that this facile and effective strategy can shed light on the development of advanced phosphate electrode materials for SIBs. [ABSTRACT FROM AUTHOR]