Metal-organic framework based composite polymer electrolytes with hierarchical pores and hydrogen bond network for efficient lithium-ion transport channels in solid-state batteries

The irregular ion channels of composite polymer electrolytes (CPEs) lead to slow ion transport kinetics and uneven lithium deposition. Herein, CPEs (UIO66@67-L) composed of hierarchical porous UIO66@67 core-shell heterostructure and bridged Li6.4La3Zr1.4Ta0.6O12 (LLZTO) fillers are designed. Due to the abundant metal sites and capillary effect of UIO66@67 with gradient pore channels, more free lithium-ions can be released to improve uniform lithium-ion flux inside the UIO66@67. Meanwhile, the doping LLZTO constructs a three-dimensional interconnected ion-conducting network through the strong hydrogen bonds between UIO66@67 and LLZTO, providing the regular ion channels between fillers. Benefiting from hierarchical pore-hydrogen bond bridging engineering, efficient ion transport channels are constructed between UIO-66, UIO-67 and LLZTO, improving lithium-ions transfer kinetics and suppressing lithium dendritic growth. As a result, a large lithium-ions migration number of 0.7 and high ionic conductivity of 5.87 x 10-4 S cm-1 can be obtained. This strategy provides an effective solution to achieve regular ions channels and high-speed lithium-ions transport for CPEs.