Effect of AlPO[sub 4]-Nanoparticle Coating Concentration on High-Cutoff-Voltage Electrochemical Performances in LiCoO[sub 2]

coating thickness on cathodes was controlled in the range on the order of 10-100 nm by changing the -nanoparticle concentration in the coating solution. The specific capacity and cycle-life performance of the coated cathodes had a strong correlation with the coating concentration (thickness). The cycle-life performance of the 1.0 wt % -coated cathodes had the best cycling stability, showing 149 mAh/g capacity retention with 4.8 V charge cutoff by 50 cycles at 1 C (=140 mA/g) rate after precycles. However, the bare cathode showed zero capacity retention at the same condition after only 20 cycles. As the coating concentration was increased to 3.2 wt %, the amount of Co dissolution into the electrolyte decreased. In contrast, the 1.0 wt % -coated cathode showed the best cycling stability, possibly due to the suppression of Li diffusivity decay and the appropriate electronic conduction. © 2004 The Electrochemical Society. All rights reserved.