posted on 2024-03-07, 14:06authored byLiuyi Hu, Tianqi Yang, Xiang Yan, Yaning Liu, Wenkui Zhang, Jun Zhang, Yang Xia, Yao Wang, Yongping Gan, Xinping He, Xinhui Xia, Ruyi Fang, Xinyong Tao, Hui Huang
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.