A high silica content substrate, such as for a thin-film battery, is provided. The substrate has a high silica content, such as over 90% by weight silica, and is thin, for example less than 500 μm. The substrate may include a surface with a topography or profile that facilitates bonding with a coating layer, such as a coating of an electrochemical battery material. The high silica content substrate may be flexible, have high temperature resistance, high strength and/or be non-reactive. The substrate may be suitable for use in the high temperature environments used in many chemical deposition or formation processes, such as electrochemical battery material formation processes.