Sputtered Porous Li-Fe-P-O Film Cathodes Prepared by Radio Frequency Sputtering for Li-ion Microbatteries

V. Sugiawati , Florence Vacandio (1) , C. Perrin-Pellegrino (2) , A. Galeyeva , A. Kurbatov , T. Djenizian (3)

1 MADIREL - Matériaux divisés, interfaces, réactivité, électrochimie
2 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence
3 Mines Saint-Etienne, Center of Microelectronics in Provence, Department of Flexible Electronics, 13541 Gardanne

the increasing demands from micro-power applications call for the development of the electrode materials for Li-ion microbatteries using thin-film technology. Porous Olivine-type LiFePO4 (Lfp) and nASicon-type Li3fe2(po4)3 have been successfully fabricated by radio frequency (Rf) sputtering and post-annealing treatments of LFP thin films. The microstructures of the LFP films were characterized by X-ray diffraction and scanning electron microscopy. The electrochemical performances of the LFP films were evaluated by cyclic voltammetry and galvanostatic charge-discharge measurements. The deposited and annealed thin film electrodes were tested as cathodes for Li-ion microbatteries. It was found that the electrochemical performance of the deposited films depends strongly on the annealing temperature. The films annealed at 500 °C showed an operating voltage of the porous LFP film about 3.45 V vs. Li/Li+ with an areal capacity of 17.9 μAh cm−2 μm−1 at C/5 rate after 100 cycles. porous nASicon-type Li3fe2(po4)3 obtained after annealing at 700 °C delivers the most stable capacity of 22.1 μAh cm−2 μm−1 over 100 cycles at C/5 rate, with an operating voltage of 2.8 V vs. Li/Li+. the post-annealing treatment of sputtered LFP at 700 °C showed a drastic increase in the electrochemical reactivity of the thin film cathodes vs. Li+, leading to areal capacity ~9 times higher than as-deposited film (~27 vs. ~3 μAh cm−2 μm−1 ) at C/10 rate.

Domaines: Matériaux

V. Sugiawati, Florence Vacandio, C. Perrin-Pellegrino, A. Galeyeva, A. Kurbatov, et al.. Sputtered Porous Li-Fe-P-O Film Cathodes Prepared by Radio Frequency Sputtering for Li-ion Microbatteries. Scientific Reports, 2019, 9 (1), ⟨10.1038/s41598-019-47464-2⟩. ⟨hal-02649153⟩