Preparation And Properties Of Al And Cu 2D Nanosheets By Monometallic Roll Rolling

Two-dimensional（2D）metal nanomaterials（NMs）have enormous potential for applications in microelectronic devices,energy storage and catalysis due to unique properties such as high specific surface area and surface plasma excitons.At present,the research of metallic 2D NMs is dominated by gold and rhodium precious metals,and their high cost and not easy to prepare.The existing methods of preparing cheap 2D metal NMs,such as hot pressing and bimetallic rolling,are easy to oxidizing and metamorphic cheap 2D metal NMs and have low preparation efficiency.Therefore,it is necessary to develop a new cheap 2D metal NMs preparation method,which can not only obtain the 2D metal NMs that are not undamaged,but also have the advantages of low cost,high preparation efficiency and easy purification.Given this,in the work,Al and Cu 2D nanosheets（NSs）with thicknesses of about 3～5 nm were physically prepared by monometallic roll rolling using inexpensive metals Al and Cu as raw materials,and their spectral absorption,electrical conductivity and electrochemical properties were further investigated.The specific research content is summarized as follows:（1）Preparation and performance study of Al 2D NSs.The Al 2D NSs were obtained by monometallic roll rolling method using Al foil with thickness of 0.05 mm and paraffin wax as raw materials.The XRD patterns shown that with the increase of rolling times,the original grain boundary can no longer satisfy the continuous extension and thinning of Al.A new slip plane（111）needs to be generated to ensure that it continues to expand and thin until 2D nanostructures were formed,thus the crystal plane peak rose sharply.The SEM of the dispersed surface shown that the Al 2D NSs was stacked on top of each other and the sheet structure is thin with a diameter of about 15～20μm.While the AFM further shown that the thickness of Al 2D NSs is about 3～5 nm.The Al 2D NSs were dispersed into petroleum ether,acetone,DMF and NMP respectively,and found that the stronger the polarity of the dispersion solvent,the better the dispersion effect of Al 2D NSs.The absorption peaks of Al2D NSs were detected at 261 nm.The resistivity of a single 2D Al NSs is about 2.38Ω·m,while the unrolled Al foil（thickness 50μm）is about 5×10-5Ω·m,the resistivity increases significantly.Furthermore,we use lithium metal as the counter electrode and 2D Al NSs as the research electrode to assemble the half-cell.The impedance was measured using an AC potential with a frequency range of 100 KHz-100 m Hz and an amplitude of 5 m V.The unrolled Al charge transfer resistance Rct is 1003Ω,while the Al 2D NSs charge transfer resistance Rct is 178.3Ω,the impedance of Al 2DNSs was obviously reduced,which is conducive to electrochemical reaction.At the tested current density of 1 mA cm^-2,while maintaining a high capacity retention rate,the charge/discharge voltage plateau of Al 2D NSs was relatively stable during the first 100 cycles of charge/discharge,and the CE was stable at about 92.5%,showing that The good cycling stability and reversibility of Li⁺ in the embedding/deembedding process of Al 2D nanoanode materials.（2）Preparation and performance study of Cu 2D NSs.Preparation and dispersion of dissolved Cu 2D NSs in the same way.The XRD patterns shown that during the rolling process,the grain size decreased,and the peak strength of（111）and（200）crystal faces decreased obviously compared with（220）crystal faces.The SEM of the dispersed surface shown that the Cu 2D NSs was stacked on top of each other and the sheet structure is thin with a diameter of about 15～20μm.While the AFM further shown that the thickness of Cu 2D NSs is about 3～5 nm.The absorption peaks of Cu 2D NSs and Pyrrolidone-copper complexwere detected at 268 and 280 nm,respectively.