Surface modification of LiFePO4 nanoparticles through an organic/inorganic hybrid approach and its impact on electrochemical properties

Chemical surface modification, using an hybrid organic/inorganic approach and its impact on the electrochemical response of a nanometric lithium iron phosphate obtained by the facile solvothermal method using an organic capping agent is investigated. Removal of the capping agent was realized through different approaches, such as washing with an organic solvent, chemical treatments, and ligand exchange with redox mediator having electrochemical activity close or not to the one of the material, to maintain the material’s morphology and structure. The redox mediator grafting approach appears very interesting, since an unpredicted impact on the electrochemical activity of the material was observed. In that case, while materials structure and morphology are fully preserved, a more or less important change of the electrochemical curve shape depending on the redox potential of the grafted molecule was observed, which suggest that this approach could be a good alternative to traditional carbon coating, facilitate recycling and bring new functionalities to positive electrode materials.