“…On the replacement of V 5+ by Li + , structure of the systems becomes more open due to transition from VO 4 tetrahedral to VO 5 trigonal bipyramid as discussed in physical parameters and structural properties. This structural change is responsible for a significant increase in oxygen vacancies with an increase in hopping of ions which leads to an increase in conductivity 4,5,42 . In addition, decrement in density, inter-ionic distance, polaron radius and optical band gap of the samples also support this increasing trend of conductivity with the addition of Li 2 O It is observed that the transport mechanism in lithium vanadate systems is attributed to small polaron hopping (SPH) between V 4+ to V 5+ states, which is increased by the addition of lithium into vanadium.…”