Calcination effect on particle morphologies and electrochemical performances of Na3V2(PO4)3/C composites as cathode for sodium-ion batteries

Abstract

Abstract Series of Na3V2(PO4)3/C composites were synthesized through the self-catalysed sol–gel route followed by subsequent optimization of calcination process. Changes on the nanoparticle morphologies and electrochemical behaviour corresponding to the different decomposition temperature (calcined at 800 °C, 850 °C, 900 °C and 950 °C) were evidently discovered. XRD diffraction results indicated similar peak patterns reflected by each series which were well-indexed to the R-3c space group under the rhombohedral NASICON structure. Driven by elevated calcination temperature, significant impact on single phase crystallinity and nanoparticle morphologies nature of the Na3V2(PO4)3/C were compared among each composite. This phenomenon creates a pertinent effect towards discharged capacity profiles and cyclic performance abilities. Under optimum heat treatment parameters, Na3V2(PO4)3/C composite electrode exhibited two potential plateaus at 3.4 V and 1.5-1.6 V (vs Na+/Na) with specific capacities of 111 - 115 mA h g-1 under moderate cyclic performance. This preliminary result indicate that calcination parameters highly induced the Na3V2(PO4)3/C electrode performance for sodium ion batteries.