The effect of electrolyte on the electrochemical properties of Na/α-NaMnO2 batteries

• Pure α-NaMnO2 was successfully synthesized by a solid-state reaction at 750 °C.
• Na/α-NaMnO2 battery has many plateau voltages in the charge/discharge curve.
• The capacity of the Na/α-NaMnO2 battery with 1 M NaClO4 EC/DEC electrolyte is higher than that with 1 M NaBF4 TEGDME.
• Na/α-NaMnO2 battery with 1 M NaBF4 TEGDME electrolyte has better stability for the 20th cycle from coulombic efficiency result than the battery with 1 M NaClO4 EC/DEC electrolyte because of stability of interfacial resistance.

Pure α-NaMnO2 cathode materials were prepared by solid-state reaction with Mn2O3 and Na2CO3 at 750 °C. Electrochemical properties of Na/α-NaMnO2 battery was investigated with electrolytes as 1 M NaClO4 EC/DEC and 1 M NaBF4 TEGDME. First discharge capacity of Na/α-NaMnO2 cell using 1 M NaClO4 EC/DEC electrolyte and 1 M NaBF4 TEGDME electrolyte was 146 mAh g−1 and 136 mAh g−1 discharge capacity for the first cycle at 0.2 C rate and 104 mAh g−1 97 mAh g−1 after 20 cycles, respectively. Na/α-NaMnO2 battery with 1 M NaClO4 EC/DEC electrolyte shows higher initial charge/discharge capacity than that using 1 M NaBF4 TEGDME because of high ionic conductivity of electrolyte and low interfacial resistance between the electrolyte and electrode. However, Na/α-NaMnO2 battery with 1 M NaBF4 TEGDME electrolyte has better stability for the 20th cycle from coulombic efficiency result because of stability of interfacial resistance.

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