High-rate intercalation capability of NaTi2(PO4)3/C composite in aqueous lithium and sodium nitrate solutions

The nanodispersed NaTi2(PO4)3/C composite containing 20–25 wt.% of in-situ formed carbon, was synthesized by gel combustion procedure followed by a heat treatment at 650, 700 and 750 °C. The samples calcined at 700 and 750 °C displayed crystalline nasicon structure. They were subjected to the investigation of intercalation/deintercalation kinetics in aqueous NaNO3 and LiNO3 solutions, using cyclic voltammetry and galvanostatic charging/discharging measurements. As regards to the effect of electrolyte composition, the reactions were evidenced to be roughly twice faster in sodium nitrate than in lithium nitrate solution. Among the samples treated at 700 and 750 °C, better performance was evidenced for the sample treated at lower temperature. Coulombic capacity in NaNO3 solution at charging rate 1C amounted to ∼70 mAh g−1 and ∼55 mAh g−1 for the sample calcined at 700 and 750 °C, respectively, and displayed surprisingly slight dependence on charging rate up to even 100C.