A Composite of Hierarchical Porous MOFs and Halloysite Nanotubes as Single‐Ion‐Conducting Electrolyte Toward High‐Performance Solid‐State Lithium‐Ion Batteries

Abstract

Metal-organic frameworks (MOFs), as a promising rechargeable electrochemical energy storage material have emerged in the field of solid-state lithium batteries. However, low ionic conductivity and high interfacial impedance still severely hamper the application of MOF-based solid-state electrolytes (SSE). In this work, a novel hierarchical porous H-ZIF-8 solid-state electrolyte (SSE) material is harvested through the in situ growth of zinc nitrate hydroxide nanosheets, expressing excellent ion conductivity of 1.04 × 10^-3 S cm^-1 and Li⁺ -transference number of 0.71. Moreover, the morphology and structure of H-ZIF-8 is further optimized to obtain a composite H-ZIF-8/HNT by decorating halloysite nanotubes (HNT). Notably, functionalized H-ZIF-8/HNT as an electrolyte presents obvious enhancement on electrochemical properties: higher ionic conductivity of 7.74 × 10^-3 S cm^-1 , better single-ion transmittability ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msub><mml:mi>t</mml:mi> <mml:msup><mml:mi>Li</mml:mi> <mml:mo>+</mml:mo></mml:msup> </mml:msub> <mml:annotation>${t}_{{\mathrm{Li}}^{+}}$</mml:annotation></mml:semantics> </mml:math> = 0.84), good interfacial compatibility as well as excellent rate performance. More importantly, the Li/LiFePO₄ battery equipped with H-ZIF-8/HNT SSE has efficient lithium-dendrite suppression and up to 84% capacity retention (104.16 mA h g^-1 ) after 200 times galvanostatic charge/discharge cycles. This work enriches the solid-state lithium-ion composite electrolyte materials, opening an entirely new way for enhancing electrochemical performance.