Étude des propriétés électrochimiques de nouveaux matériaux nanostructurés à base de fer préparés par chimie douce et utilisables comme électrodes positives d'accumulateurs au lithium

TL;DRAbstract

In the search for new positive electrode materials for lithium batteries, iron compounds are interesting due to their low cost and toxicity. For this purpose, b-FeOOH, g-FeOOH and LiFePO4 were studied.<br />For oxyhydroxides, direct addition of acetylene black or carbon nanotubes (for the improvement of the electronic conductivity) was developed, which leads to non-uniform deposition and isolation of the grains, unfavorable for lithium insertion. A partial substitution of iron by cobalt was performed (improvement of the ionic conductivity). A stabilization of the exchangeable quantity of lithium is obtained with an optimum.<br />For LiFePO4, several synthesis modes were performed (hydrothermal, mechanical activation, coprecipitation) to obtain different particles sizes. The electronic conductivity is enhanced by generation of a carbon layer onto the particles from thermal degradation of a carbohydrate. It appears that the finest the particles are, the best the insertion is. Crystallogr

Chat with Paper

AI Agents for this Paper