Electrochemical Investigation of Spherical Hard Carbon Negative Electrodes for Sodium Secondary Batteries

Hard carbon (HC) is receiving widespread attention as a negative electrode material for sodium secondary batteries. In this study, spherical HC with three different diameters (1 p.m, 1.5 p.m, and 5 p.m) are investigated using ionic liquid (IL) and organic electrolytes. The HC with a diameter of 5 p.m demonstrated the best performance with IL at 90 degrees C (capacities of 327 mAh g-1 at 20 mA g-1 and 77 mAh g-1 at 2000 mA g-1 and initial Coulombic efficiency of 78.9 %). The HCs showed stable cycling in ILs as compared to the organic electrolytes in the first few cycles.

Automated summary

Hard carbon (HC) with three different diameters (1 pm, 1.5 pm, and 5 pm) was investigated as a negative electrode material for sodium secondary batteries using ionic liquid (IL) and organic electrolytes. HC with a diameter of 5 pm showed the best performance in IL at 90 degrees C, with capacities of 327 mAh g-1 at 20 mA g-1 and 77 mAh g-1 at 2000 mA g-1, and an initial Coulombic efficiency of 78.9%. The HCs exhibited stable cycling in ILs compared to organic electrolytes in the initial cycles.