Behaviour of titanium species in molten Li2CO3+Na2CO3 and Li2CO3+K2CO3 in the anodic conditions used in molten carbonate fuel cells II. Electrochemical intercalation of Li+ in Li2TiO3 at 600 and 650 degrees C

The electrochemical behaviour of titanium electrodes is studied in molten L i2CO3 + Na2CO3 and Li2CO3 + K2CO3 under the anodic conditions used in molte n carbonate fuel cells. Although Ti(IV), in a Li2TiO3 form, is the only sta ble titanium species in these media, experimental evidence of electrochemic al activity is given by cyclic voltammetric experiments. A thorough analysi s of the change in peak currents with scan rate is in agreement with an int ercalation-deintercalation phenomenon occuring at the Li2TiO3 surface, form ed chemically at the titanium electrode. The amount of charge measured in a ll the redox processes corroborates the hypothesis of a lithium intercalati on. Crystallographic data relative to lithium titanate show that the voltam metric peaks can be attributed to insertion sites within the lattice of thi s compound. (C) 1999 Elsevier Science S.A. All rights reserved.