Phosphorus Based Ceramics for Positive Electrode Synthesis and Characterization

Abstract

Historically, the LiCoO 2 is the most used as active material for battery positive electrode because of its great potential (3.7 - 4.2 V), its interesting specific capacity (150 mA·h·g -1 ) and its excellent life cycle [1] 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F005200650066003300390038003500370036003700340032000000 . However, its toxicity, the cobalt cost and its structural instability oriented research towards new materials more stable that can replace it. In another context, hybrid, electrical vehicles and communication (computers and mobile phones...) have increased the scientific and technological research for new materials capable of storing and return energy through a system called accumulator. And research has identified the phosphate olivine structure as the most prolific ceramic material for positive electrode. LiFePO 4 is a promising cathode material for Lithium-ion batteries. It provides high thermal stability and is synthesized using low cost materials. Unfortunately LiFePO 4 suffers from a low electrical conductivity, which is harmful to its electrochemical performance. Decreasing the particle size, coating the particles with carbon or doping with metal atoms can increase the conductivity of the material. In this paper, we present the synthesis, physico-chemical and electrical characterization of lithium and iron doped Al-phosphorrus-based ceramic. The NPK Fertiliser was used as Al and phosphorus precursors. The powder XRD spectrum shows a possible presence of LiFePO 4 and Fe 2 (PO) 3 in theheterostrcture. An important quantity of Al is found by EDX spectra which supposed that the most important based atom is Aluminum and not Phosphorus. This can explain the increase of the conductivity value 10 2 times more important than those found in the literature for LiFePO 4 .