Na-ion batteries have been gaining in popularity in recent years due to their
potentially low cost and relatively high energy density for large-scale
applications. Non-graphitized carbons are among the most popular anodes for
practical use in Na-ion batteries due to efficient Na storage and relatively low
production costs, but the role of electrolytes in determining Na-ion capacity and
binding mechanism is poorly studied. In this work, we systematically studied the
influence of three sodium salts (NaPF6, NaFSI, NaTFSI) or five electrolytes in
organic carbonate solvents EC and DMC on cycling stability and charge transfer
kinetics of the non-graphitized carbon anode in Na-ion battery, using
galvanostatic intermittent titration technique (GITT) and galvanostatic cycling.
Based on the experimental data, the most promising electrolytes for the specific
anode material are containing NaFSI salt. This was determined by the fact that
these two electrolytes exhibit highest values of diffusion coefficients obtained by
the GITT measurements. The addition of 0.1 M NaFSI in commercial 1 M
NaPF6 in EC : DMC (1 : 1 vol. %) also exhibits the highest capacity (270 mAh/g)
in the electrochemical analysis of galvanostatic cycling in addition to high
capacity retention during 70 cycles
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