Characteristics of LiFePO4/C composite prepared by sonochemical method under multibubble sonoluminescence

Abstract

LiFePO4/C composites with various weight percent of carbon nanotubes (CNT) were prepared through one-pot sonochemical method under the condition of multibubble sonoluminescence (MBSL). The electrical performance of the composites depends crucially on ultrasound irradiation time, the calcination temperature and duration and weight percent of CNTs. The best initial discharge capacity was obtained for a calcination temperature of 650 A degrees C for 6 h, 30minutes ultrasound irradiation and with 2 wt% of CNTs. The electric conductivity of the LiFePO4/C composite with 2 wt% CNTs was approximately 3.4 center dot 10(-4) S/cm. The coin cell made of LiFePO4/C composite whose average diameter is 683 nm exhibits an initial discharge capacity of 142mAh/g at 0.1 C, a flat and long voltage plateau and low Delta V between the initial charge and discharge plateaus of 0.03 V and small fade rate of capacity of 0.08% per cycle at 0.5 C. The first efficiency, the ratio of the initial discharge to the initial charge capacity, of the LiFePO4/C composite, is about 90%.