Ye Zhengqing, Jiang Ying, Yang Tianyu, Li Li, Wu Feng, Chen Renjie
Beijing Key Laboratory of Environmental Science and Engineering, School of Material Science & Engineering, Beijing Institute of Technology, Beijing, 100081, China.
Advanced Technology Research Institute, Beijing Institute of Technology, Jinan, 250300, China.
Adv Sci (Weinh). 2022 Jan;9(1):e2103456. doi: 10.1002/advs.202103456. Epub 2021 Oct 27.
Sluggish sulfur reduction and lithium sulfide (Li S) oxidation prevent the widespread use of lithium-sulfur (Li-S) batteries, which are attractive alternatives to Li-ion batteries. The authors propose that a transition metal selenide heterojunction (CoSe-ZnSe) catalytically accelerates bidirectional sulfur conversion reactions. A combination of synchrotron X-ray absorption spectroscopy and density functional theory calculations show that a highly active heterointerface with charge redistribution and structure distortion effectively immobilizes sulfur species, facilitates Li ion diffusion, and decreases the sulfur reduction and Li S oxidation energy barriers. The CoSe-ZnSe catalytic cathode exhibits high areal capacities, good rate capability, and superior cycling stability with capacity fading rate of 0.027% per cycle over 1700 cycles. Furthermore, CoSe-ZnSe heterojunctions anchored on graphene aerogels (CoSe-ZnSe@G) enhance ionic transport and catalytic activity under high sulfur loading and lean electrolyte conditions. A high areal capacity of 8.0 mAh cm is achieved at an electrolyte/sulfur ratio of 3 µL mg . This study demonstrates the importance of bidirectional catalytic heterojunctions and structure engineering in boosting Li-S battery performances.
缓慢的硫还原和硫化锂（Li₂S）氧化阻碍了锂硫（Li-S）电池的广泛应用，而锂硫电池是锂离子电池颇具吸引力的替代方案。作者提出，过渡金属硒化物异质结（CoSe₂-ZnSe）可催化加速双向硫转化反应。同步加速器X射线吸收光谱和密度泛函理论计算相结合表明，具有电荷重新分布和结构畸变的高活性异质界面能有效固定硫物种，促进锂离子扩散，并降低硫还原和Li₂S氧化的能垒。CoSe₂-ZnSe催化阴极具有高面积容量、良好的倍率性能和优异的循环稳定性，在1700次循环中容量衰减率为每循环0.027%。此外，锚定在石墨烯气凝胶上的CoSe₂-ZnSe异质结（CoSe₂-ZnSe@G）在高硫负载和贫电解质条件下增强了离子传输和催化活性。在电解质/硫比为3 μL mg⁻¹时，实现了8.0 mAh cm⁻²的高面积容量。这项研究证明了双向催化异质结和结构工程在提升锂硫电池性能方面的重要性。
