Influence of the morphology on the Li insertion properties of Li1.1V3O8

Abstract

Two Li_1.1V₃O₈ samples have been prepared by heating a sol–gel precursor at 350 and 650 °C, i.e. below and above the melting point, respectively. Their electrochemical lithium insertion behavior was investigated after different grinding treatments. Important differences were observed, both in initial capacity and in cyclability. Attempts were made to correlate these differences to the material characteristics (composition, morphology and structure). The importance of grain morphology (size, size distribution and shape) and texture (agglomeration of smaller particles or not) has been evidenced. The size and agglomeration of the grains play a major role on the initial capacity, while their crystal shape (well formed crystals or no crystal shape) seems to be the main factor influencing the cyclability. This latter morphology feature was also shown to affect differently the partial capacity fading occurring on each electrochemical Li insertion process.