LiFePO₄ thin film deposition onto Ag coated glass by RF magnetron sputtering

Smart wearable technology devices need nano-scaled energy storages. The battery materials should be improved for higher performance. So, this study was focused on surface, microstructure and electrochemical performance analyses of the nanolayered Olivine type of the LiFePO₄ cathode's thin film deposition onto Ag coated glass. The LiFePO₄ layer was deposited by RF magnetron sputtering using a pure argon atmosphere. The surface analysis of the cathode layer was done by field emission scanning electron microscopy. The measured diameters of the LiFePO₄ spheres were approximately 10–20 nm. The electrochemical properties of the deposited LiFePO₄ thin film deposition onto Ag coated glass were tested in liquid electrolyte, using indium tin oxide (ITO) coated glass as the opposite electrode. A potentiostat/galvanostat was used for the cyclic voltammetry and electrochemical impedance spectroscopy. A Nyquist graph of the prepared open cell in liquid electrolyte was obtained. The grain size of the deposited layers strongly depended on the electrochemical properties of the layer. The cell assembled by the deposited LiFePO₄ cathode thin film and the ITO coated glass (used as an anode) were tested. The capacity of the cell was measured as to be 150 nAh cm⁻². To determine the value of the equivalent circuit elements of the assembled cell, the Randles cell model was used. The Warburg diffusion element value for the assembled cell was estimated to be 0.0002 S.s^−0.5. (paper)