Fig. 2: Water-trapping in electrolyte phase and interface adsorption on HC of locking-chain 15PBS additive.

a Schematic illustration of water-trapping by 15PBS. b Electrostatic potential (ESP) mapping image of 15PBS. c Adsorption energies of H₂O-H₂O, −SO₃⁻-H₂O, 15–C–5-H₂O and 15PBS-H₂O calculated by DFT calculations. d Fitted Raman spectra of different electrolytes (line: fitted data; dot: pristine data). e ¹⁹F NMR spectra of different electrolytes after storage for 7 days at 60 °C. f Radical distribution function and Na⁺ coordination number of investigated baseline electrolyte and 15PBS electrolyte. g Schematic illustrations of solvation structure. h Raman spectra of baseline electrolyte and 15PBS electrolyte. i EDL capacitance of HC electrodes using different electrolytes by three-electrode systems. Error bars are standard deviations based on three individual tests, and the center metric of the error bars is the average of three tests. j DFT calculations for adsorption energy of H₂O, EC, DEC, NaPF₆ and 15PBS on graphene sheets with different environments. k, C K-edge synchrotron soft XAS spectra for pristine HC, HC electrodes soaked in different electrolytes, respectively.