1 Supporting Information Formation of Reversible Solid Electrolyte Interface on Graphite Surface from Concentrated Electrolytes Dongping Lu, 1,* Jinhui Tao, 2 Pengfei Yan, 3 Wesley A. Henderson, 1 Qiuyan Li, 1 Yuyan Shao, 1 Monte L. Helm, 2 Oleg Borodin, 4 Gordon L. Graff, 1 Bryant Polzin, 5 Chong-Min Wang, 3 Mark Engelhard, 3 Ji- Guang Zhang, 1 James J. De Yoreo, 2 Jun Liu, 1 and Jie Xiao 1,* 1 Electrochemical Materials & Systems Group, Energy & Environment, Directorate, Pacific Northwest National Laboratory (PNNL), Richland, WA 99352 (USA) 2 Physical Sciences Division, Fundamental & Computational Sciences Directorate, Pacific Northwest National Laboratory (PNNL), Richland, WA 99352 (USA) 3 Environmental Molecular Sciences Laboratory (EMSL), Pacific Northwest National Laboratory, Richland, WA 99352 (USA) 4 Electrochemistry Branch, Sensor & Electron Devices Directorate, U.S. Army Research Laboratory (ARL), Adelphi, MD 20783 (USA) 5 Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (USA) Corresponding authors: Dongping.lu@pnnl.gov and jiexiao@uark.edu Table S1. Composition and physical parameters of the graphite electrode (CGP-A12 is Conoco Phillips). Composition (wt%) Porosity (%) Thickness (μm) CGP-A12 ( Timcal C45 carbon Oxalic acid PVDF Cu foil Coating Total 89.8 4 0.17 6 38.8 10 43 53