Electronic and Ionic Conductivities of LiNi1/3Mn1/3Co1/3O2-Li3PS4Positive Composite Electrodes for All-Solid-State Lithium Batteries

Electronic and ionic conductivities of positive composite electrodes composed of LiNi1/3Mn1/3Co1/3O2 and Li3PS4 were measured by both DC and AC techniques. Two cell configurations of (a) electron-blocking cells and (b) ion-blocking cells were applied for the measurements. The conductivities determined by the DC technique showed a good agreement with those measured by the AC technique, which suggests that both the DC and AC techniques are useful for the measurements of the electronic and ionic conductivities. The electronic conductivities for the composite electrodes at the state of charge (SOC) 0% were lower than the ionic conductivities. The electronic conductivities drastically increased at SOC 50% and became higher than or equal to the ionic conductivities. Cell capacities were evaluated based on the electronic and ionic conductivities. At a high current density of 1.3 mA cm-2, cell capacities seemed to be associated with the ionic conductivities of the composite electrodes.