In Situ Construction of Dual‐Functional UiO‐66‐NH ₂ Coated Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ to Achieve Lithium Metal Cells with Efficient Ion Transport in Quasi‐Solid Electrolytes

The NASICON-type Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) is a promising solid-state electrolyte for lithium batteries due to its high lithium-ion conductivity and air stability. However, its practical application in composite solid polymer electrolytes (CSPEs) is limited by high interfacial impedance, the polymer's inherently low lithium-ion (Li⁺) conductivity, and side reactions with lithium metal electrodes. U66N@LATP with a core-shell structure is synthesized by growing UiO-66-NH₂ in situ on LATP nanoparticles and incorporating it into the PVDF-HFP matrix to address these issues. The UiO-66-NH₂ coating protects LATP from reacting with lithium metal electrodes and enhances Li⁺ transport by providing a high Li⁺ concentration environment. The U66N@LATP-based Li-symmetric cell exhibits superior stability in long-cycle tests (>1000 h, 0.2 mA cm^-2) compared to the sample without the core-shell structure. The assembled LiFePO₄ (LFP)|CSPE|Li cell maintains a discharge capacity of 105.7 mAh g^-1 with 93.8% capacity retention over 1500 cycles at 10 C. A pouch cell further validates the practical potential of U66N@LATP/CSPE in solid-state lithium batteries. This study offers a simple and efficient core-shell architecture design strategy to mitigate LATP side reactions and reduce the interfacial impedance, thereby improving the overall performance of the electrolyte system.