The LiFe(<inf>1-x</inf>)V<inf>x</inf>PO<inf>4</inf>/C composite synthesized by gel-combustion method, with improved rate capability and cycle life in aeratedaqueous solutions

Abstract

The nitrate-(glycine + malonic acid)-assisted gel-combustion process, followed by a heat treatment at 750°C under reductive atmosphere, was used as a fast and effective way to synthesize vanadium dopedolivine incorporated in carbon matrix, of general formula LiFe(1-x)VxPO 4/C. The two-phased Rietveldrefinement confirmed that vanadium incorporation into olivine structure was complete. The heatingunder reduction atmosphere caused the formation of iron phosphide to some extent, the concentrationwas determined by Rietveld analysis. The capacity and rate capability of these composites were testedby both cyclic voltammetry and galvanostatic cycling. Specifically, the average discharging capacities ofthe composite with x = 0.055, determined in an saturated aqueous LiNO3 solution equilibrated with air,at the rates of 1, 10 and 100 C, amounted to 91, 73 and 35 mAh g-1, respectively, with no perceivablecapacity fade. © 2013 Elsevier Ltd. All rights reserved.