Composite-Structure Materials for Na-Ion Batteries

Due to the growing concern of aggravated environmental problems (air pollution, global warming, etc.) and Li resources, Na-ion batteries have received significant attention as a promising alternative. Many electrode materials for Na-ion batteries have been reported in the past, especially over the past five years. However, most of these materials have a single crystalline structure and exhibit a limited electrochemical performance. Recently, some electrode materials with composite structures have been reported for both Li-ion and Na-ion batteries and have attracted attention because of their enhanced comprehensive electrochemical performance. Herein, a detailed discussion on the development of these composite-structure materials for Na-ion batteries is conducted based on the crystalline structure. The structure design, identification, and adjustment of these materials are thoroughly discussed. Furthermore, the future outlook based on a mechanism analysis and a new electrode-material structure system is also introduced in this work, by reviewing previous important studies on composite-structure materials.