Fig. 5: High temperature performance of different electrolytes in 346.3 Wh kg–1 SiOx (900 mAh g–1)||Ni90 pouch cells.

a 19F NMR spectra of different electrolytes after 7 days storage at 45 °C. b Binding energies of HF and PF5 with QSE or Upy-QSE, respectively. c Cycling performance of SiOx (900 mAh g–1)||Ni90 pouch cells with different electrolytes at 45 °C. d Gas generation of SiOx (900 mAh g–1)||Ni90 pouch cells after cycling at 45 °C. e Gas components generated in (d). f Mechanism illustration of CO2 evolution in FEC-based electrolyte.