Facile Synthesis of Two-Dimensional Natural Vermiculite Films for High-Performance Solid-State Electrolytes

Ceramic electrolytes hold application prospects in all-solid-state lithium batteries (ASSLB). However, the ionic conductivity of ceramic electrolytes is limited by their large thickness and intrinsic resistance. To cope with this challenge, a two-dimensional (2D) vermiculite film has been successfully prepared by self-assembling expanded vermiculite nanosheets. The raw vermiculite mineral is first exfoliated to thin sheets of several atomic layers with about 1.2 nm interlayer channels by a thermal expansion and ionic exchanging treatment. Then, through vacuum filtration, the ion-exchanged expanded vermiculite (IEVMT) sheets can be assembled into thin films with a controllable thickness. Benefiting from the thin thickness and naturally lamellar framework, the as-prepared IEVMT thin film exhibits excellent ionic conductivity of 0.310 S center dot cm(-1) at 600 degrees C with low excitation energy. In addition, the IEVMT thin film demonstrates good mechanical and thermal stability with a low coefficient of friction of 0.51 and a low thermal conductivity of 3.9 x 10(-3) W center dot m(-1)center dot K-1. This reveals that reducing the thickness and utilizing the framework is effective in increasing the ionic conductivity and provides a promising stable and low-cost candidate for high-performance solid electrolytes.

Automated summary

A 2D vermiculite film with thin thickness and naturally lamellar framework has been successfully prepared. This film exhibits excellent ionic conductivity and holds potential as a stable and low-cost candidate for high-performance solid electrolytes.