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°C

The electrochemical behaviour of titanium electrodes is studied in molten Li2CO3 + Na2CO3 and Li2CO3 + K2CO3 under the anodic conditions used in molten carbonate fuel cells. Although Ti(IV), in a Li2TiO3 form, is the only stable titanium species in these media, experimental evidence of electrochemical activity is given by cyclic voltammetric experiments. A thorough analysis of the change in peak currents with scan rate is in agreement with an intercalation-deintercalation phenomenon occuring at the Li2TiO3 surface, formed chemically at the titanium electrode. The amount of charge measured in all the redox processes corroborates the hypothesis of a lithium intercalation. Crystallographic data relative to lithium titanate show that the voltammetric peaks can be attributed to insertion sites within the lattice of this compound. (C) 1999 Elsevier Science S.A. All rights reserved.