| 摘要 |
The present invention aims to provide a sodium secondary battery which is prevented from losing capacity when a charging and discharging cycle is repeated, can operate at low temperatures, has substantially increased output voltages and a substantially increased charging speed, has charging/discharging cycle properties which can be maintained for a long period of time, is prevented from being degraded, has an extended lifespan, and has enhanced stability. According to the present invention, the sodium secondary battery includes graphite felt which is a positive electrode current collector impregnated in electrolyte, has the maximum porosity on the surface facing a solid electrolyte. The porosity of the graphite felt decreases in the widthwise direction. |
