Author: Kristian B. Kvamme
Title: Phosphites as precursors in thin film synthesis. Using LiPO as cathode coating in Li-ion batteries
Affiliation: University of Oslo
Phosphate based materials show great promise as electrolytes in solid state batteries. The ideal solid state electrolyte should be thin and uniform. For these reasons Atomic layer deposition (ALD) has been suggested as a good synthesis route for solid state electrolytes. In this work a new route for synthesising phosphorous based material using ALD is demonstrated. Phosphite precursors have been used for the synthesis of LiPO and AlPO materials. This is done by replacing phosphate precursors with phosphite precursors in established ALD synthesis routes. Furthermore the LiPO product has been deposited as a coating layer onto LiFePO4 cathodes to improve kinetics and low current density cycling performance. We have shown that there is indeed an improvement at coating thicknesses of 1 nm or less. The materials themselves have been characterised using XPS and XRF for composition analysis, and cyclic voltammetry and galvanostatic cycling for electrochemical analysis.