Barium vanadium pentoxide-based compounds preparedvia a sol–gel process and their evaluation as lithium intercalation materials

Abstract

The sol–gel process has allowed us to synthesize two new specimens of barium vanadium pentoxide-based compounds: (i) an oxidized orthorhombic Ba–V oxide (referred to as oxidized ‘BVO’), whose formula Ba_0.18V₂O_5.15is close to that of a mixed oxide; (ii) a reduced monoclinic Ba–V oxide (referred to as reduced ‘BVO’), with formula Ba_0.18V₂O_4.95 . Both materials are obtained after specific heat-treatment of the barium exchanged xerogel. The electrochemical features of lithium insertion in both compounds are reported. The oxidized and reduced ‘BVO’ have different and peculiar electrochemical behaviour, which is discussed in connection with that of the parent orthorhombic V₂O₅ oxide and the monoclinic Na_0.33V₂O₅ bronze, respectively.