Electrochemical In-Situ Conductivity Measurements for Thin Film of Li_1-xMn₂O₄ Spinel

Electrical conductivity of LiMn 2 O 4, which is a promising cathode active material for lithium ion batteries, was monitored in situ during electrochemical lithium extraction and reinsertion reactions in 1 M LiClO 4 propylene carbonate solution. The in-situ conductivity measurement was achieved by means of an interdigitated microarray electrode coated with a uniform and dense film of LiMn 2 O 4 . The conductivity of Li 1 - x Mn 2 O 4 was found to exhibit a peak-shaped profile as a function of lithium content. The conductivity of Cr 3+ -doped spinel, LiMn 1.95 Cr 0.05 O 4, decreased monotonically with decreasing lithium content. These results are discussed by considering the effects of phase transformation on the conductivity of these materials.