MXene-rGO aerogel assisted Na3.5MnTi(PO4)3 cathode for high-performance sodium-ion batteries

[Display omitted] •MXene-rGO aerogel greatly improves conductivity for sodium storage.•Na3.5MnTi(PO4)3 in situ grows on MXene-rGO with large specific surface area.•N3.5MTP@MXene-rGO exhibits high power density long cycle life over 5000 cycles.•N3.5MTP@MXene-rGO performs good specific capacity at low temperature of −30 °C. Sodium superionic conductor (NASICON) structured polyanionic materials have recently attracted great attention for robust crystal structures. However, inherent properties of NASICON presents poor electrical conductivity and low energy density. Herein, non-stoichiometric synthesized strategy is used for acquiring N3.5MTP, effectively suppressing voltage hysteresis. Besides, as-fabricated N3.5MTP grains in-situ grow on MXene-rGO aerogels by sol–gel synthesis approach obtaining N3.5MTP@MXene-rGO. MXene-rGO aerogel as an excellent conductive matrix can effectively avoid agglomeration of Na3.5MnTi(PO4)3 particles and alleviate volume change of the lattice during sodium ion intercalation/deintercalation. Moreover, cross-linked network of N3.5MTP@MXene-rGO provides fast electron transfer and ion transport rates. The above synergistic effect and contribution of pseudocapacitance make it an excellent discharge capacity of 189 mA h g−1 at 50 mA g−1 for N3.5MTP@MXene-rGO, long cycles of 5000 cycles, as well as 98 mA g−1 at −30 °C (50 mA g−1). Prospectively, this study provides an effective strategy for improving electrochemical performance of NASICON-type cathode for sodium batteries.