Abstract
Li-O2 batteries with ultrahigh theoretical energy densities usually suffer from low practical discharge capacities and inferior cycling stability owing to the cathode passivation caused by insulating discharge products and by-products. Here, a trifunctional ether-based redox mediator, 2,5-di-tert-butyl-1,4-dimethoxybenzene (DBDMB), is introduced into the electrolyte to capture reactive O2− and alleviate the rigorous oxidative environment of Li-O2 batteries. Thanks to the strong solvation effect of DBDMB towards Li+ and O2−, it not only reduces the formation of by-products (a high Li2O2 yield of 96.6 %), but also promotes the solution growth of large-sized Li2O2 particles, avoiding the passivation of cathode as well as enabling a large discharge capacity. Moreover, DBDMB makes the oxidization of Li2O2 and the decomposition of main by-products (Li2CO3 and LiOH) proceed in a highly effective manner, prolonging the stability of Li-O2 batteries (243 cycles at 1000 mAh g−1 and 1000 mA g−1).
| Original language | English (US) |
|---|---|
| Journal | Angewandte Chemie - International Edition |
| DOIs | |
| State | Published - Jul 21 2020 |
Bibliographical note
KAUST Repository Item: Exported on 2020-10-01Acknowledgements: This work was financially supported by the National Key R&D Program of China (2017YFA0206700), the National Natural Science Foundation of China (21725103, 51702314), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA21010210), the Jilin Province Science and Technology Development Plan Funding Project (20180101203JC), the K. C. Wong Education Foundation (GJTD-2018-09), the Changchun Science and Technology Development Plan Funding Project (19SS010) and the National & local united engineering lab for power battery. The Supercomputing USTC is acknowledged for computational support.