Enhanced low-temperature sodium storage kinetics in a NaTi2(PO4)3@C nanocomposite

Sodium-ion batteries (SIBs) are attracted increasing interest for commercial electrical energy storage systems as an economic alternative of lithium-ion batteries (LIBs) due to the rich abundance, evenly distributed and favorable price of sodium resources. But the sluggish in diffusion and huge volume variations during (de)sodiation are considered to be the intrinsic drawbacks to limit the further development of SIBs. Suitable electrodes are thus desired. Sodium super ionic conductor (NASICON) materials are considered to be the most promising electrodes owing to their open three-dimensional (3D) skeleton structure and high ionic conductivity, yet they suffer from the inferior electrical conductivity. Herein, a composite of carbon-incorporated fine NaTi2(PO4)3 (NTP) nanocrystalline (Nano NTP@C in abbreviation) is developed. It displays an excellent sodium storage performance as the anode for SIBs, delivering high sodium storage capacity of 132 mAh g−1 at 0.2 C (1 C = 133 mAh g−1), remarkable rate capability (80 mAh g−1 at a high rate of 50 C) and along with super-long cycle life (87.5% capacity retention at 50 C over 1000 cycles). Besides, the Nano NTP@C also demonstrates a low-temperature sodium storage performance (e.g., showing high discharge capacities of 72 mAh g−1 (10 C) and 60 mAh g−1 (20 C) at −20 °C). [Display omitted] •Uniform carbon-coated NaTi2(PO4)3 nanograins (20–50 nm, Nano NTP@C) are produced.•Enhanced sodium storage kinetics, especially at low temperatures, is demonstrated.•At −20 °C, the Nano NTP@C can operate well (60 mAh g−1) at a high rate of 20 C.