Single‐Ion Conductive Bacterial Cellulose Membrane Towards High Performance Lithium‐Oxygen Batteries

Bacterial cellulose (BC) as a natural polymer possessing ultrafine nanofibrous network and high crystallinity, leading to its remarkable tensile strength, moisture retention and natural degradability. In this study, we revealed that this BC membrane has excellent affinity to organic electrolyte, high ionic conductivity and inherent ion selectivity as well. Due to its ability of migrating lithium ions and suppressing the shuttling of anions across the membranes, it is deemed as available model for iodide‐assisted lithium‐oxygen batteries (LOBs). The cycle life of the LOBs significantly extends from 74 rounds to 341 rounds at 1.0 A g−1 with a fixed capacity of 1000 mAh g−1, when replacing glass fiber (GF) by BC membrane. More importantly, the rate performance improves significantly from 42 to 36 cycles to 215 and 116 cycles after equipping with the BC membrane at 3.0 and 5.0 A g−1. Surprisingly, the full discharge capacity dramatically enhanced by ca. eight times from 4,163 mAh g−1 (GF) to 32,310 mAh g−1 (BC). Benefited from the convenient biosynthesis, cost‐effectiveness and high chemical‐thermal stability, these qualities of the BC membrane accelerate the development and make it more viable for application in advancing next‐generation environmentally friendly LOBs technology with high energy density.