SELECTIVE ELECTROINSERTION OF LITHIUM IONS INTO A PT/LAMBDA-MNO2 ELECTRODE IN THE AQUEOUS PHASE

The electrochemical insertion of alkali-metal ions in the aqueous phase was investigated by using a Pt/lambda-MnO2 electrode which was obtained by the electrochemical extraction of Li+ from a Pt/LiMn2O4 electrode. The cyclic voltammogram of a 0.01 mol/dm3 LiCl solution showed a definite electric current, corresponding to the Li+ insertion/extraction reaction with a lambda-MnO2 electrode involving the redox of manganese. The same electrodes in a 0.01 mol/dm3 NaCl or KCl solution showed little electric current in the region between 0.2 and 1.0 V vs calomel electrode. Only Li+ ions were taken up by the Pt/lambda-MnO2 electrode from a mixed solution of alkali-metal chlorides.