ELECTROCHEMICAL PROPERTIES OF LOW-TEMPERATURE CRYSTALLIZED LICOO2

Electrochemical properties of low temperature (LT) crystallized LiCoO2 are investigated. LT LiCoO2 was obtained by a precipitation process i n aqueous solution and a final heat-treatment at 400 degrees C in air. Potentiometric, voltammetric, and ac impedance experiments are perfor med as well as x-ray diffraction measurements on electrochemically del ithiated compounds. LT LiCoO2 shows electrochemical and structural pro perties quite different from that exhibited by the high temperature (H T) LiCoO2. The main differences appear in terms of practical voltage, reversibility, Li transport in oxide, and structural changes as Li is deintercalated. This work clearly proves the 3D character of LT LiCoO2 (spinel-like structure). In spite of a lower working potential and a satisfactory capacity (Delta x = 0.5), the LT LiCoO2 is highly reactiv e toward the electrolyte and is characterized by a slower Li transport than in layered HT LiCoO2.