Analysis of Electrochemical Properties of Li Iron Phosphate Cathode Material Doped with Aluminium

Abstract

With the advent of Phospho-Olivines as cathode material for rechargeable lithium ion batteries in 1997 by Padhi et.al. intensive study with primary focus on LiFePO4 have been carried out owing to its certain advantages like low cost, non – toxic, environmental friendly, and high safety . Even with cathode materials like LiCoO2 with higher capacity than the LiFePO4, LiFePO4 is proven to be more stable since it is more tolerant to overcharge and discharge. However, the theoretical capacity is not attained till date at 1C current. The major problem lies with the low electronic conductivity and slow Li ion diffusion. To improve the conductivity several techniques have been proposed like carbon coating technique, heavy cation doping into the olivine structure etc. In this paper LiFePO4 was selectively doped with aluminum at the Fe position retaining the olivine structure and synthesized using a novel modified solid state synthesis method.