A new treatment of LiV3O8 has been proposed for improving its electrochemical behavior as a cathode material for secondary lithium batteries. The ultrasonically treated products in water were characterized by x-ray diffractometry, thermogravimetric analysis, scanning electron microscopy, and specific surface area measurements. These measurements showed that the ultrasonic treatment process of crystalline LiV3O8 causes a decrease in crystallinity and considerable increases in specific surface area and interlayer spacing. The product, ultrasonically treated In water for 3 h and then heat-treated at 250 degrees C for 6 h, showed a high initial discharge capacity of 283 mAh/g active material, which was 62% higher than that of the starting material, and was charge-discharge cycled without a large capacity loss during 40 cycles. The ultrasonic treatment of LiV3O8 can improve not only the specific capacity but also the cycling behavior.