A low-overpotential, long-life, and “dendrite-free” lithium-O₂ battery realized by integrating “iodide-redox-phobic” and “Li-ion-philic” membrane

Before the practical application of the Li–O₂ battery (LOB), a critical issue regarding large overpotential upon charging (which causes irreversible side reactions and low energy efficiency) should be resolved. The utilization of redox mediators (RMs) which oxidatively decompose insulating discharge product, Li₂O₂, is one promising solution to address this issue. However, the soluble RMs can easily diffuse to and react with the Li metal anode (encountering Li dendrites is even worse). Here, a chemical self-assembly strategy is introduced into the fabrication of the iodide-redox-phobic and Li-ion-philic membrane for LOBs, in which the electronegative δ-MnO₂ layer is in-situ grown on commercial polyethylene (PE) membrane (MnO₂@PE). The electronegative MnO₂ layer can simultaneously repel the shuttle of iodide species and regulate the uniform Li ⁺ deposition. Controlling cut-off capacity of 1000 mAh g⁻¹, iodide-redox-based LOB with MnO₂@PE demonstrates low overpotentials (∼0.7 V vs. Li⁺/Li), dendrite-suppressing capability, as well as impressive long-term reversibility over 500 cycles (2000 h), which urges the LOB technology competitive among the next-generation rechargeable power systems.