As an innovative renewable energy harvester, the tribovoltaic nanogenerator (TVNG) with lower impedance and DC characteristics has attracted much attention. To alleviate the issues of severe wear for hard–hard semiconductor materials, here, a soft ion dielectric material and semiconductor TVNG based on n-Si/gel polymer electrolyte (GPE) (GPE-TVNG) is proposed. A solid ionic electric double layer (i-EDL) model is established to systematically explore the generation mechanism as well. Moreover, the proposed i-EDL model is verified by subsequent experiments, and the results manifest that the ion directed migration can improve the output performance of GPE-TVNG. The optimized GPE-TVNG has a short-circuit current of 26.5 μA and a low matched impedance of 60 kΩ, which is far lower than the previous reported internal resistance of Si-based TVNG (>100 kΩ). This study broadens the selection of TVNG materials and realizes the effective control of TVNG output.