Sodium-Based Dual Carbon Batteries with Graphene-Like Graphite: Achieving High Reversible Capacity and Stable Cycling

Abstract

Sodium-based dual carbon batteries (Na-DCBs) are promising next-generation secondary batteries with low environmental impact and minimal resource risk, as they can be constructed without lithium ions, transition metal oxides in the cathode, or copper current collectors in the anode. Our previously reported carbon material, referred to as graphene-like graphite (GLG), exhibits a higher reversible capacity than graphite when used as a cathode active material in lithium-based dual carbon batteries. Additionally, it shows comparable performance to hard carbon as an anode material for sodium-ion batteries. Therefore, in this study, we fabricated a Na-DCB using GLG as both electrodes and evaluated its performance in full-cell configuration. Precycling of the anode facilitated the formation of a stable solid electrolyte interphase (SEI), enabling highly reversible charge–discharge cycles in the full-cell configuration. When the upper cutoff voltage was set to 4.5 V, the maximum capacity reached 139 mAh g⁻¹ based on the mass of the cathode active material. This value largely exceeds previously reported capacities of DCB full cells with graphite cathodes. These results clearly demonstrated the feasibility of constructing high-capacity Na-DCBs using GLG as active materials.