Shandong Engineering Research Center of Green Manufacturing for New Chemical Materials, School of Chemistry and Chemical Engineering, Yantai University, Yantai, 264005, P. R. China.
Key Laboratory for Special Functional Aggregate Materials of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China.
Small. 2023 Jun;19(25):e2207924. doi: 10.1002/smll.202207924. Epub 2023 Mar 16.
The sluggish reaction kinetics and severe shutting behaviors of sulfur cathodes are the major roadblocks to realizing the practical application of lithium-sulfur (Li-S) batteries and need to be solved through designing/constructing rational sulfur hosts. Herein, an effective alternative material of Fe O /FeP in-situ embedded in N-doped carbon-tube (Fe O /FeP/NCT) is proposed. In this fabricated heterostructure, NCT skeleton works as a sulfur host provides physical barrier for lithium polysulfides (LiPSs), while Fe O /FeP heterostructure with abundant oxygen vacancies provides double active centers to simultaneously accelerate e /Li diffusion/transport kinetics and catalysis for LiPSs. Through the respective advantages, Fe O /FeP/NCT exhibits synergy enhancement effect for restraining sulfur dissolution and enhancing its conversion kinetics. Furthermore, the promoted ion diffusion kinetics, enhanced electrical conductivity, and increased active sites of Fe O /FeP/NCT are enabled by oxygen vacancies as well as the heterogeneous interfacial contact, which is clearly confirmed by experimental and first-principles calculations. By virtue of these superiorities, the constructed cathode shows excellent long-term cycling stability and a high-rate capability up to 10 C. Specially, a high areal capacity of 7.2 mAh cm is also achieved, holding great promise for utilization in advanced Li-S batteries in the future.
硫阴极的缓慢反应动力学和严重的关闭行为是实现锂硫 (Li-S) 电池实际应用的主要障碍，需要通过设计/构建合理的硫主体来解决。在此，提出了一种有效的替代材料，即在氮掺杂碳管（FeO/FeP/NCT）中原位嵌入的 FeO/FeP。在这种制备的异质结构中，NCT 骨架作为硫主体提供了对多硫化锂 (LiPSs) 的物理阻挡，而具有丰富氧空位的 FeO/FeP 异质结构提供了双重活性中心，同时加速了 e/Li 的扩散/传输动力学和 LiPSs 的催化作用。通过各自的优势，FeO/FeP/NCT 对抑制硫溶解和提高其转化动力学表现出协同增强效应。此外，氧空位和非均匀界面接触还提高了 FeO/FeP/NCT 的离子扩散动力学、导电性和活性位点，这通过实验和第一性原理计算得到了明确证实。凭借这些优势，所构建的阴极表现出优异的长期循环稳定性和高达 10C 的高倍率能力。特别地，还实现了 7.2mAhcm 的高面容量，为未来在先进的 Li-S 电池中的应用提供了巨大的潜力。
