The electrolytes of 1 M NaFSI dissolved in various carbonate solvents containing EC, PC and/or DMC have been
investigated to find out the most compatible electrolyte composition with hard carbon (HC) anode in Na-ion battery
(NIB). The physical properties including viscosity and conductivity were measured to correlate with the electrochemical
behaviors of these electrolytes. The Na/HC half-cell was used for testing the charge/discharge performance of prepared
electrolytes at room temperature. This best medium for the solvation of NaFSI salt is the mixture of EC, PC and DMC
with the ratio 3:1:1, respectively. Indeed, this electrolyte delivered a highest capacity of 335.6 mAh.g-1, excellent capacity
retention of 73.7% for 100 cycles.