Direct measurement of the chemical reactivity of silicon electrodes with LiPF6-based battery electrolytes

We report the first direct measurement of the extent of the spontaneous non-electrochemically driven reaction between a lithium ion battery electrode surface (Si) and a liquid electrolyte (1.2 M LiPF6–3 : 7 wt% ethylene carbonate : dimethyl carbonate). This layer is estimated to be 35 Å thick with a SLD of ∼ 4 × 10−6 Å−2 and likely originates from the consumption of the silicon surface.