Three-Dimensional Ordered Macroporous FePO4 as High-Efficiency Catalyst for Rechargeable Li-O2 Batteries

The Li-O-2 battery is receiving much recent attention because of its superhigh theoretical energy density. However, its performance is limited by the irreversible formation/decomposition of Li2O2 on the cathode and the undesired electrolyte decomposition. In this work, low-cost three-dimensional ordered. macroporous (3DOM) FePO4 is synthesized by using polystyrene (PS) spheres template in a facile experimental condition and applied as a high-efficiency catalyst for rechargeable Li-O-2 batteries, including good rate performance, high specific capacity, and perfect cycling stability. The superior performances can be attributed to the unique structure of 3DOM FePO4 cathodes, which can provide an efficient buffer space for O-2/Li2O2 conversion. In addition, it is demonstrated that the Li+ intercalation/deintercalation behavior of 3DOM FePO4 in ether-based electrolyte can contribute to capacity for Li-O-2 batteries over cycling. As a result, when there is no O-2 in the environment, the Li-O-2 cell can also be operated as a rechargeable Li-FePO4 cell with a perfect cycle capability.