Intercalación electroquímica de litio en K1.2Ti8O16 y síntesis de nuevos bronces K1.2-xTi8O16

In this work we present the electrochemical lithium intercalation in K 1.2 Ti 8 O 16 which crystallizes in the hollandite-type structure. Between 2.5 and 0.5 V two different reduction processes have been detected. A first process in the range 1.8-1.3 V vs. Li corresponds to the insertion of approximately 1 Li per formula, whereas the second process occurs at a lower potential completing the insertion of almost 2 lithium ions per formula at a minimum potential of 0.5 V. The average potential of 1.5 V corresponds to a specific capacity of 40 Ah/Kg of active material. This value is too low for using this material as the positive electrode. However, according to the low average potential it may be used as the negative electrode in rechargeable lithium ion batteries (rocking chair) if a substantial increase of the amount of intercalated lithium would be achieved. For this reason compounds K 1.2-x Ti 8 O 16 have been prepared using topotatic oxidation reactions. These compounds are actually under study.