title: Three-Dimensional, Fibrous Lithium Iron Phosphate Structures Deposited by Magnetron Sputtering.
abstract: Crystalline, three-dimensional (3D) structured lithium iron phosphate (LiFePO4) thin films with additional carbon are fabricated by a radio frequency (RF) magnetron-sputtering process in a single step. The 3D structured thin films are obtained at deposition temperatures of 600 °C and deposition times longer than 60 min by using a conventional sputtering setup. In contrast to glancing angle deposition (GLAD) techniques, no tilting of the substrate is required. Thin films are characterized by X-ray diffraction (XRD), Raman spectrospcopy, scanning electron microscopy (SEM), cyclic voltammetry (CV), and galvanostatic charging and discharging. The structured LiFePO4+C thin films consist of fibers that grow perpendicular to the substrate surface. The fibers have diameters up to 500 nm and crystallize in the desired olivine structure. The 3D structured thin films have superior electrochemical properties compared with dense two-dimensional (2D) LiFePO4 thin films and are, hence, very promising for application in 3D microbatteries.
authors.affiliation: Institute of Energy and Climate Research, Materials Synthesis and Processing (IEK-1), Forschungszentrum Jülich GmbH , 52425 Jülich, Germany.
authors.forename: Aiko
authors.initials: A
authors.lastname: Bünting
authors.affiliation: Institute of Energy and Climate Research, Materials Synthesis and Processing (IEK-1), Forschungszentrum Jülich GmbH , 52425 Jülich, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Uhlenbruck
authors.affiliation: Institute of Energy and Climate Research, Materials Synthesis and Processing (IEK-1), Forschungszentrum Jülich GmbH , 52425 Jülich, Germany.
authors.forename: Doris
authors.initials: D
authors.lastname: Sebold
authors.affiliation: Institute of Energy and Climate Research, Materials Synthesis and Processing (IEK-1), Forschungszentrum Jülich GmbH , 52425 Jülich, Germany.
authors.forename: H P
authors.initials: HP
authors.lastname: Buchkremer
authors.affiliation: Institute of Energy and Climate Research, Materials Synthesis and Processing (IEK-1), Forschungszentrum Jülich GmbH , 52425 Jülich, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Vaßen
keywords: 3D microbattery; fibrous structures; lithium iron phosphate; lithium-ion battery; magnetron sputtering; nanostructured electrodes