Wen Bo, Huang Yaohui, Jiang Zhuoliang, Wang Yuzhe, Hua Weibo, Indris Sylvio, Li Fujun
State Key Laboratory of Advanced Chemical Power SourcesFrontiers Science Center for New Organic Matter, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin, 300071, China.
School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shanxi, 710049, China.
Adv Mater. 2024 Aug;36(32):e2405440. doi: 10.1002/adma.202405440. Epub 2024 Jun 2.
Light-assisted Li-O batteries exhibit a high round-trip efficiency attributable to the assistance of light-generated electrons and holes in oxygen reduction and evolution reactions. Nonetheless, the excitonic effect arising from Coulomb interaction between electrons and holes impedes carrier separation, thus hindering efficient utilization of photo-energy. Herein, porphyrinic metal-organic frameworks with (FeNi)O(COO) clusters are used as photocathodes to accelerate exciton dissociation into charge carriers for light-assisted Li-O batteries. The coupling of Ni 3d and Fe 3d orbitals boosts ligand-to-metal cluster charge transfer, and hence drives exciton dissociation and activates O for superoxide (O ) radicals, rather than singlet oxygen (O) under photoexcitation. These enable the light-assisted Li-O batteries with a low total overvoltage of 0.28 V and round-trip efficiency of 92% under light irradiation of 100 mW cm. This work highlights the excitonic effect in photoelectrochemical processes and provides insights into photocathode design for light-assisted Li-O batteries.
光辅助锂氧电池具有较高的往返效率，这归因于光生电子和空穴在氧还原和析出反应中的辅助作用。尽管如此，电子与空穴之间的库仑相互作用产生的激子效应阻碍了载流子分离，从而妨碍了光能的有效利用。在此，具有(FeNi)O(COO)簇的卟啉金属有机框架被用作光阴极，以加速激子解离成载流子，用于光辅助锂氧电池。Ni 3d和Fe 3d轨道的耦合促进了配体到金属簇的电荷转移，从而驱动激子解离，并在光激发下将O激活为超氧根(O)自由基，而不是单线态氧(O)。这些使得光辅助锂氧电池在100 mW cm的光照下总过电压低至0.28 V，往返效率达到92%。这项工作突出了光电化学过程中的激子效应，并为光辅助锂氧电池的光阴极设计提供了见解。
