Oxygen Assisted Lithium‐Iodine Batteries: Towards Practical Iodine Cathodes and Viable Lithium Metal Protection Strategies

Abstract Rechargeable batteries with iodine‐based cathodes have recently been the subject of significant interest due to the moderately high theoretical specific energy (≈600 Wh kg⁻¹) and high‐rate capability (>5 C) of the iodine cathode. Progress however has been impeded by the relatively low iodine contents of reported iodine‐based cathodes. This is likely due to high rates of poly‐iodide shuttling and cell instability that takes place at higher cell loadings. To reinforce the lithium metal anode, oxygen gas is introduced in the cells, which leads to a more robust solid‐electrolyte interphase (SEI) layer, improving cell stability. This oxygen‐assisted lithium‐iodine (OALI) battery overcomes many of the shortcomings of other reported lithium‐iodine batteries by utilizing a simple to fabricate lithium iodide (LiI) on activated carbon cathode with cell operating under an oxygen containing atmosphere to realize high‐rate capability (>50 mA cm⁻²) and high areal capacity (>12 mAh cm⁻²).