The complex surface reactions contribute to the formation of solid-electrolyte interphases (SEI), and cause the irreversible capacity loss of silicon (Si) electrodes. The chemical and mechanical instability of the interphases finally leads to performance degradation. A microscopic characterization of the electrical properties at the interface is expected to gain information to understand the physical and chemical evolution caused by the formation of SEI, and provide the guidance for improvements in performance. The microscopic electrical characterization techniques, including Kelvin probe force microscopy (KPFM) and scanning spreading resistance microscopy (SSRM), have been applied to silicon electrodes. The nanoelectrical probes have been developed in one atomic force microscopy (AFM)-based platform, and the complementary electrical characterizations can be performed on the same sample area in nm-scale. Based on the contact potential difference method, KPFM maps the work function (WF) on electrode surfaces, which is expected to largely change with lithiation and delithiation. WF is sensitive to Li-ion distribution and diffusion, which can be highly inhomogeneous in nm-scale and can be assessed and evaluated from the KPFM mapping. Local conductivity/resistivity of Li-ion electrodes has been studied by SSRM. Based on the contact mode of AFM, SSRM maps of local resistivity in 10-nm resolutions have been acquired by applying a voltage between the probe and a sample and measuring the current through the probe. Ex-situ measurements along the Lithiation/delithiation process have been performed to understand the formation of SEI and the impact of electrochemical reaction on the electrical properties of SEI. Figure 1 shows the SSRM resistance changes before and after lithiation of Si electrode. The inhomogeneity with grain and domain sizes of 200-500 nm is observed at the surface of Si electrode. Surface modification by using atomic layer deposition and molecular layer deposition has also been used to modify the surface chemistry of silicon electrodes. This presentation will discuss the evolution in nm-scale resistance of SEI during electrochemical reactions, and the impact of surface coating materials on the electrical properties of SEI. Figure 1