fig4
![Fundamentals and perspectives of electrolyte additives for non-aqueous Na-ion batteries](https://image.oaes.cc/30caa1ee-dd04-4fda-a1cc-dc765ffe2987/em3022.fig.4.jpg)
Figure 4. XPS spectra of HC electrodes after 135 cycles in half-cells with NaPF6/EC:DMC electrolyte. The effect of 3% FEC: (A), (B) C1s and (C) F1s; the effect of 3% DMCF: (D), (E) C1s and (F) F1s. Reproduced from ref[24], copyright 2020 IOP Publishing Limited. DMC: Dimethyl carbonate; DMCF: fluorinated dimethyl carbonate; EC: ethylene carbonate; FEC: fluoroethylene carbonate; HC: hard carbon; XPS: X-ray photoelectron spectroscopy.