Effects of Mg Ion Doping on the Electrochemical Performances and Structure of LiFePO_4/C

Abstract

Stoichiometric Mg-doped LiFePO_4/C cathode material was synthesized through a template- solid state reaction in an inert atmosphere using magnesium lactate as dopant and part of carbon source. Effects of Mg~(2+)doping on the electrochemical and physical performances of the cathode materials were investigated.At 1/3C discharge rate,the secondly reversible specific capacity of the Mg-doped LiFePO_4/C is nearly 20mAh/g higher than that of the undoped one.After 20 cycles,the capacity of the former is 162.1mAh/g,22mAh/g higher than that of the latter.Impedance R_(ct)of the Mg-doped material is 120Ω,while that of the undoped material is 180Ω.The tap density of Mg-doped material is also improved by 0.229g.cm~(-3)compared with undoped material.