title: High Cycling Stability and Extreme Rate Performance in Nanoscaled LiMn2O4 Thin Films.
abstract: Ultrathin LiMn2O4 electrode layers with average crystal size of ∼15 nm were fabricated by means of radio frequency sputtering. Cycling behavior and rate performance was evaluated by galvanostatic charge and discharge measurements. The thinnest films show the highest volumetric capacity and best cycling stability, retaining the initial capacity over 70 (dis)charging cycles when manganese dissolution is prevented. The increased stability for film thicknesses below 50 nm allows cycling in both the 4 and 3 V potential regions, resulting in a high volumetric capacity of 1.2 Ah/cm3. It is shown that the thinnest films can be charged to 75% of their full capacity within 18 s (200 C), the best rate performance reported for LiMn2O4. This is explained by the short diffusion lengths inherent to thin films and the absence of phase transformation.
authors.affiliation: KU Leuven , Department of Physics, Celestijnenlaan 200D and ‡KU Leuven Centre for Surface Chemistry and Catalysis, 3001 Leuven, Belgium.|Imec , Kapeldreef 75, 3001 Leuven, Belgium.
authors.forename: Brecht
authors.initials: B
authors.lastname: Put
authors.affiliation: Imec , Kapeldreef 75, 3001 Leuven, Belgium.
authors.forename: Philippe M
authors.initials: PM
authors.lastname: Vereecken
authors.affiliation: Imec , Kapeldreef 75, 3001 Leuven, Belgium.
authors.forename: Nouha
authors.initials: N
authors.lastname: Labyedh
authors.affiliation: Imec , Kapeldreef 75, 3001 Leuven, Belgium.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Sepulveda
authors.affiliation: Imec , Kapeldreef 75, 3001 Leuven, Belgium.
authors.forename: Cedric
authors.initials: C
authors.lastname: Huyghebaert
authors.affiliation: Imec , Kapeldreef 75, 3001 Leuven, Belgium.
authors.forename: Iuliana P
authors.initials: IP
authors.lastname: Radu
authors.affiliation: KU Leuven , Department of Physics, Celestijnenlaan 200D and ‡KU Leuven Centre for Surface Chemistry and Catalysis, 3001 Leuven, Belgium.
authors.forename: Andre
authors.initials: A
authors.lastname: Stesmans
keywords: Li-ion recharegeable battery; LiMn2O4; cathode; nanostructured; rate performance; thin film