钠离子电池为什么能反复充电放电？

How do sodium ions conduct electricity?    

钠离子电池能够实现数千次反复充放电，核心原因是钠离子嵌脱反应具备高度可逆性，电极材料结构稳定性优异。在正常充放电工况下，钠离子从正负极材料晶格中嵌入和脱出时，不会破坏电极材料的基础晶体结构，不会出现晶格坍塌、材料粉化、活性物质失效等不可逆损坏。整个储能和释能过程仅为物理嵌脱为主、轻微可逆化学反应为辅，无原料消耗、无成分变质，充放电完成后电极材料可恢复初始状态。同时，成熟的电解液和隔膜体系能够稳定支撑离子循环迁移，配合BMS系统的精准保护，有效规避过充过放、过流等损伤问题，因此电池可以长期反复充放电使用，实现长循环寿命。

The conduction mode of Sodium-ion Battery is divided into internal ion conduction and external electron conduction, and the two circuits cooperate to complete energy transmission, which is also the general conduction logic of all secondary intercalation batteries. The inside of the battery is an ion conduction circuit: during the charge and discharge process, sodium ions migrate directionally in the electrolyte, shuttle between the cathode and anode, and realize internal charge conduction by ion movement, without electrons directly passing through the inside of the battery. The outside of the battery is an electron conduction circuit: while ions migrate, electrons form a directional flow through external wires and load equipment, output current and drive the equipment to work. The internal and external circuits cooperate and operate synchronously to form a complete closed circuit, which not only realizes the storage of electrical energy, but also can stably output power to ensure the normal operation of the equipment.