Electrochemical performance of magnetron sputter deposited LiFePO4-Ag composite thin film cathodes

✍ Scribed by K.-F. Chiu; C.-L. Chen

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 892 KB
• Volume: 205
• Category: Article
• ISSN: 0257-8972
• DOI: 10.1016/j.surfcoat.2010.07.069

✦ Synopsis

LiFePO 4 thin films have been sputtered from a pure LiFePO 4 target onto Ag/SS, Ag/Si 3 N 4 /Si and Si 3 N 4 /Si substrates. All of the deposited films were annealed at 973 K for 1 hr in H 2 /Ar (5 %) atmosphere. Substrate induced microstructural and crystallographic evolutions have been observed by a scanning electron microscope and X-ray diffraction. Energy dispersion spectra and X-ray photoelectron spectra revealed that Ag was mixed in the LiFePO 4 films deposited on Ag under layers. Ceramic metal composite thin films were obtained. The film conductivity (1 × 10 -3 Scm -1 ) is therefore elevated by an order of six, compared with pure LiFePO 4 (10 -9 Scm -1 ). The electrochemical measurements of the LiFePO 4 -Ag films showed a flat plateau at 3.4 V (v.s. Li/Li + ) and a reversible capacity of 80 mAh/g. Optimization of Ag contents may further improve the discharge capacity.