Sol-Gel Synthesis of Iron-Manganese Mixed Oxide as Superior and Eco-Friendly Anode for Lithium-Ion Batteries

Lithium-ion batteries (LIBs) are the perfect balance between portability, low cost and good performances. Considering the anodic side, graphite is the most used active material 1, which despite its wide use, and a specific capacity of 372 mAhg-1, has been included in the European Commission list of critical raw materials that have to be replaced in the future. For this reason, a great deal of effort has been devoted to investigate a relatively new class of materials emerged in this last few years, showing a different reactivity from traditional insertion materials, the so-called conversion materials. Among these, transition metal oxides (TMOs), can reach extremely high capacity values, up to five times higher than graphite 2. Despite this, they have evidenced several drawbacks: short cyclic life, a large first cycle irreversible capacity, and a relevant volume variation during cycling. In this work, an Iron-Manganese mixed oxide was synthesized by Sol-Gel method and tested as anode for Li-ion batteries. In order to address the aforementioned drawbacks, and improve the mechanical stability of the electrodes, improved binders with superior mechanical properties 3, such as Polyacrylic Acid (PAA) and Sodium-Carboxymethyl Cellulose (Na-CMC), and an environmentally friendly electrode processing using ethanol or H2O as solvents, were evaluated. The experimental data shown superior performance with respect to the standard Polyvinylidene Fluoride system, which makes use of the expensive and toxic N-Methyl-2-pyrrolidone (NMP) solvent. References: 1 Scrosati, B.; Garche, J.; Journal of Power Sources 2010, 195, 2419-2430. 2 Cabana, J.; Monconduit, L.; Larcher, D.; Palacìn M.R.; Advanced Material 2010, 22, 170-192. 3 Magasinski, A.; Zdyrko, B.; Kovalenko, I.; Hertzberg, B.; Burtovyy, R.; Huebner, C.F.; Fuller, T.F.; Luzinov, I.; Yushin, G.; ACS Applied Materials & Interfaces 2010, 2, 3004-3010.