K-BETA-FERRITE AS A NEW CATHODE ACTIVE MATERIAL FOR LITHIUM SECONDARYBATTERY()

The possibility of K+-beta-ferrite (K1.33Fe11O17) as a cathode active material for lithium secondary battery was investigated. It was confir med that lithium ions certainly inserted into K+-beta-ferrite. Li cont ent y in LiyK1.33Fe11O17 Was increased up to 6.79. Most of lithium ion s seem to enter into gamma-Fe2O3 layers of K+-beta-ferrite, because al kali layers could contain only 2 alkali ions for Fe11O17. According to the cyclic voltammogram, good reversibility was observed in insertion and extraction of lithium ions. The discharge potential decreased to 1.5V vs. Li/Li+ and the charge potential increased to 4.5V vs. Li/Li+. The capacity of K+-beta-ferrite has reached 200Ah/kg.