High-Entropy Laminates with High Ion Conductivities for High-Power All-Solid-State Lithium Metal Batteries

Solid-state electrolytes (SSEs) are crucial to high-energy-density lithium metal batteries, but they commonly suffer from slow Li+ transfer kinetics and low mechanical strength, severely hampering the application for all-solid-state batteries. Here, we develop a two-dimensional (2D) high-entropy lithium-ion conductor, lithium-containing transition-metal phosphorus sulfide, HE-Li (x) MPS3 (Li (x) (Fe1/5Co1/5Ni1/5Mn1/5Zn1/5)PS3) with five transition-metal atoms and lithium ions (Li+) dispersed into [P2S6](2-) framework layers, exhibiting high lattice distortions and a large amount of cation vacancies. Such unique features enable to efficiently accelerate the migration of Li+ in 2D [P2S6](2-) interlamination, delivering a high ionic conductivity of 5 x 10(-4) S cm(-1) at room temperature. Moreover, the HE-Li-x MPS3 laminate can be employed as a building block to construct an ultrathin SSE film (similar to 10 mu m) based on strong C-S bonding between HE-Li (x) MPS3 and nitrile-butadiene rubber. The SSE film delivers a strong mechanical robustness (6.0 MPa, 310% elongation) and a high ionic conductivity of 4 x 10(-4) S cm(-1), showing a long cycle stability of 800 h in lithium symmetric cells. Coupled with LiFePO4 cathode and lithium anode, the all-solid-state battery presents a high Coulombic efficiency of 99.8% within 2000 cycles at 5.0 C.

Automated summary

In this study, a two-dimensional high-entropy lithium-ion conductor with high ionic conductivity and good mechanical stability was developed for all-solid-state batteries, showing improved performance.