Optimizing the Performance of a Graphitized Carbon Xerogel as Cathode for Sodium Dual‐Ion Batteries

Abstract

Abstract The objective of this study is to optimize the performance of a graphitized carbon xerogel doped with graphene oxide (GXGO) as cathode for sodium dual‐ion batteries. Carbon xerogels are synthetic materials produced in large amounts, with well‐controlled chemistry, porosity and structure, by a simple and fast microwave process that has been scaled‐up. The intercalation of PF6− anions from various NaPF6 salt‐based electrolytes in a GXGO‐based cathode is investigated by considering the influence of the upper cut‐off voltage (UCOV) and of the electrolyte on the electrochemical parameters. The best results were attained in an electrolyte with a 2.0 M NaPF6 concentration in EC : EMC carbonate solvent mixture with added FEC, at a UCOV of 5.0 V. GXGO cathode provides a discharge capacity of 47 mAh g−1 after 2500 cycles with a coulombic efficiency of 97 %. Moreover, it shows great cycling stability and capacity retention of essentially 100 % after the initial cycles.

Keywords

• Carbon xerogel
• Cathode
• PF6− anion intercalation
• Sodium dual-ion battery