Lithiation/Delithiation Synthesis of Few Layer Silicene Nanosheets for Rechargeable Li–O2 Batteries

Abstract

Silicene has recently received increasing interest due to its unique properties. However, the synthesis of silicene remains challenging, which limits its wide applications. In this work, a top-down lithiation and delithiation process is developed to prepare few layer silicene-like nanosheets from ball-milled silicon nanopowders. It is found that delithiation solvent plays a critical role in the structure evolution of the final products. The use of isopropyl alcohol renders 2D silicene-like products 30–100 nm in length and ≈2.4 nm in thickness. The electrochemical characterization analysis suggests that the product shows high performance for rechargeable Li–O₂ batteries with 73% energy efficiency and high stability. The top-down synthesis strategy proposed in this work not only provides a new solution to the challenging preparation issue of few layer silicene but also demonstrates the feasibility of producing 2D materials from nonlayered starting structures.

Few layer silicene nanosheets are successfully prepared by a lithiation/delithiation approach with controlled lithiation extent and selected delithiation agent. These crystal nanosheets with 30–100 nm length and ≈2.4 nm thickness are attached with oxygen molecules and oxygen-containing groups on their surfaces. They exhibit high catalytic performance for rechargeable Li–O₂ batteries.

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