Synthesis And Electrochemical Characterizations Of Dual Doped Li_(1.05)fe_(0.997)cu_(0.003)po_4

摘要

Dual doped Li_(1.05)Fe_(0.997)Cu_(0.003)PO_4 material was synthesized at 660 ℃ in Ar atmosphere by a solid-state method. It showed well developed XRD patterns without any impurity peaks such as FeP or metallic Fe_2P at 2θ=41°, which enhance the electrochemical capacity of the Li/LiFePO_4 system. Li_(1.05)Fe_(0.997)Cu_(0.003)PO_4 was composed of many large polycrystalline-type particles with sizes between 200 and 300 nm and small particles from 20-50 nm distributed among the larger particles. The Li/Li_(1.05)Fe_(0.997)Cu_(0.003)PO_4 cell showed the highest initial discharge capacity, greater than 145 mAh/g, which was substantially higher than the Li/ LiFePO_4 cell, 19 mAh/g, under the same test conditions. This might result from enhancement of the contact area and electrical conductivity between the small particles in the Li_(1.05)Fe_(0.997)Cu_(0.003)PO_4 from the small amount of Li and Cu substitution.