<br>原位构建富含LiF-Li3N的界面有助于全固态锂硫电池中的快速离子扩散,ACS Nano

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原位构建富含LiF-Li3N的界面有助于全固态锂硫电池中的快速离子扩散
ACS Nano ( IF 15.8 ) Pub Date : 2024-03-07 , DOI: 10.1021/acsnano.4c00267
Liuyi Hu ₁ , Tianqi Yang ₁ , Xiang Yan ₁ , Yaning Liu ₁ , Wenkui Zhang ₁ , Jun Zhang ₁ , Yang Xia ₁ , Yao Wang ₁ , Yongping Gan ₁ , Xinping He ₁ , Xinhui Xia ₁ , Ruyi Fang ₁ , Xinyong Tao ₁ , Hui Huang ₁

Affiliation

全固态锂硫电池（ASSLSB）因其超高的理论能量密度和完全避免穿梭效应的能力而受到广泛关注。然而，ASSLSBs的进一步发展受到固体电极界面较差的动力学特性的限制。通过使用硫-过渡金属和有机硫复合材料替代硫而不降低ASSLSB比容量的常见策略来实现良好的动力学性能仍然是一个巨大的挑战。在本研究中，通过将LiTFSI引入到S-KB复合材料中，构建了硫-(科琴黑)-(双三氟甲磺酰亚胺锂盐)(S-KB-LiTFSI)复合材料。初始放电容量高达1483 mA hg ^–1 ，这得益于S-KB-LiTFSI复合材料改进的离子电导率和扩散动力学，其中在循环过程中原位形成了许多具有Li ₃ N成分的LiF界面相。结合DFT计算发现，LiF和Li ₃ N的迁移势垒远小于Li ₆ PS ₅ Cl固体电解质的迁移势垒。 LiF和Li ₃ N的快离子导体不仅提高了Li ⁺传输效率，而且提高了界面稳定性。因此，组装的ASSLSB在200 mA g ^–1下稳定运行600个周期，本研究为ASSLSB的进一步开发提供了有效的策略。

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In Situ Construction of LiF–Li3N-Rich Interface Contributed to Fast Ion Diffusion in All-Solid-State Lithium–Sulfur Batteries

All-solid-state lithium–sulfur batteries (ASSLSBs) have attracted wide attention due to their ultrahigh theoretical energy density and the ability of completely avoiding the shuttle effect. However, the further development of ASSLSBs is limited by the poor kinetic properties of the solid electrode interface. It remains a great challenge to achieve good kinetic properties, by common strategies to substitute sulfur–transition metal and organosulfur composites for sulfur without reducing the specific capacity of ASSLSBs. In this study, a sulfur–(Ketjen Black)–(bistrifluoromethanesulfonimide lithium salt) (S-KB-LiTFSI) composite is constructed by introducing LiTFSI into the S-KB composite. The initial discharge capacity reaches up to 1483 mA h g^–1, benefited from the improved ionic conductivity and diffusion kinetics of the S-KB-LiTFSI composite, where numerous LiF interphases with a Li₃N component are in situ formed during cycling. Combined with DFT calculations, it is found that the migration barriers of LiF and Li₃N are much smaller than that of the Li₆PS₅Cl solid electrolyte. The fast ionic conductors of LiF and Li₃N not only enhance the Li⁺ transfer efficiency but also improve the interfacial stability. Therefore, the assembled ASSLSBs operate stably for 600 cycles at 200 mA g^–1, and this study provides an effective strategy for the further development of ASSLSBs.

更新日期：2024-03-07

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