An electrolyte consisting of lithium nitrate (LiNO₃) and lithium difluoro(oxalto)borate (LiDFOB) in ethylene carbonate (EC), ethylmethyl carbonate (EMC), and triethyl phosphate (TEP) was used to improve the long-term cycling stability of silicon anodes. TEP was selected for its ability to dissolve LiNO₃ in carbonates to a concentration of ~0.2 M. The large amount of LiNO₃ combined with the LiDFOB salt led to a capacity retention of 87.1% after one hundred cycles due to the formation of a stable solid electrolyte interphase (SEI). Ex-situ surface analysis revealed that the SEI consists of oxalates, lithium alkyl carbonates, borates, and nitrate decomposition products. By selecting two components that preferentially reduce before the rest (LiNO₃ and LiDFOB), the SEI formed was able to prevent significant solvent decomposition and allow for improved electrochemical cycling in pure silicon anodes.