In this paper, we report a high-energy-density lithium/polyiodide (Li/PI) semi-liquid battery with soluble polyiodide in ether-based solvents as the catholyte. The challenge of shuttle effect is addressed by adopting a hybrid membrane coated with negatively charged sulfonate-ended perfluoroalkyl polymer, which allows for inhibition of polyiodide shuttles due to the electrostatic repulsion. The assembled Li/PI battery demonstrates a superior volumetric energy density (170.5 Wh L−1), a stable cycling performance (>100 cycles, averaged decay < 0.16% at 0.2 C), a high energy efficiency (>84%, 100 cycles at 2 C), and a high coulombic efficiency (>95%, 100 cycles at 2 C). These high performances achieved suggest that the aprotic Li/polyiodide battery with a compact architecture has the potential for various energy storage applications.