Lithium-ion cells are potential energy storage devices in planetary exploration due to their high energy density and long lifespan. The high intensity of γ-ray radiation in outer space poses a great challenge to lithium-ion cells. In this study, radioactive Co-60 was applied as the radiation source to investigate the performance of lithium-ion cells with the electrolyte radiated by γ-rays. Two kinds of cathode (LiMn2O4, LiNi0.8Co0.15Al0.05O2) and three kinds of anode (Li, graphite, Li4Ti5O12) were examined. There are two new mechanisms in the cells with a radiated electrolyte which affect the cell voltage and cycling performance: (i) erosion of the lithium electrode in the radiated electrolyte in the cases of half cells and lithium symmetrical cells; and (ii) electrochemical reaction between carboxyl species and the lithium extracted from the cathode in the case of full cells.