ELECTROCHEMICAL INSERTION OF LITHIUM INTO YBA2CU3O7-Y

Lithium insertion into the superconductor YBa2Cu3O7-y has been studied with the cell Li\1 M LiClO4 in PC\LixYBa2Cu3O7-y. The open circuit voltage of the cell decreases gradually from 3.4 V to 2.2 V as the lithium content x increases from 0 to 0.3. Then a voltage plateau is reached that continues up to x = 1.0. The chemical diffusion coefficient of lithium has been determined by the galvanostatic intermittent titration technique. A value of 1.65 to 2.13 x 10(-7) cm2/s for x < 0.1 is obtained. The reversibility of the lithium insertion was shown by voltammetry and repeated cycling of YBa2Cu3O7-y. A battery has been made with a capacity of 24.4 mAh, corresponding to a volume capacity of 256.7 Ah/I.