Recently, attention has been given to the investigation of
glasses containing transition metal (TM) cations [1–6].
Several strategies have been used to design novel lithium
ion-conducting glasses. Lithium ion-conducting batteries
develop high-voltages and high-energy density due to their
lightweight and highly electropositive character of the
lithium metal [7]. Glasses with covalent networks often
tend to possess open structures and support high ionic
conductivities [8]. The investigation of the structure of such
materials is essential to obtain a better insight into the
structure–property relations. It is reported that lithium
borates form good glasses over a wide range of composi-
tions [9,10]. Some recent structural studies [11] show the
presence of BiO6 octahedra as the main structural unit in
the Bi2O3-based glasses containing Li
+ions. Li
+ions
occupy the interstices to compensate the excess negative
charge of BiO6 octahedra in low-alkali-content glasses,
whereas with high alkali content the replacement of some
relatively strong Bi–O bonds by weak Li
+–O bonds takes
place resulting in a decrease in the mean bond strength and
connectivity in the glass network which are responsible for
more open structure. B2O3 is a glass forming oxide whereas
Bi2O3 is a conditional glass former and the presence of
these two in the glass matrix results to a low rate of
crystallization and moisture resistant stable glasses are
formed. Boron atoms in these glasses are both three and
four- coordinated and are generally designated as B3 and
B4 units [12–19].B4 units give rise to tetrahedral network
features of the glass. The B4/B3 ratio is determined by the
concentration of the modifier lithium oxide [12,17,20]. The
addition of lithium oxide not only modifies the B–O–B
bonds, but also breaks up the tightly organized diborate
units [21]. The glass structure is also influenced by the
presence of other constituents like ZnO and CdO, as these
cations can enter the glass network both as network former
and as network modifier [22]. The concentration of each
type depends on the concentration of the oxide itself.
Therefore, the present work has been carried out to
investigate the effect of transition metal cations on the
density, molar volume, dc conductivity and structural
properties of lithium bismuth borate glasses.