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 ( <math xmlns="http://www.w3.org/1998/Math/MathML"> <semantics><msub><mi>t</mi> <msup><mi>Li</mi> <mo>+</mo></msup> </msub> <annotation>${t}_{{\mathrm{Li}}^{+}}$</annotation></semantics> </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.