Because of their exotic electronic properties and abundant active sites, two-dimensional (2D) materials have potential in various fields. Pursuing a general synthesis methodology of 2D materials and advancing it from the laboratory to industry is of great importance. This type of method should be low cost, rapid and highly efficient. Here, we report the high-yield synthesis of 2D metal oxides and hydroxides via a molten salts method. We obtained a high-yield of 2D ion-intercalated metal oxides and hydroxides, such as cation-intercalated manganese oxides (Na0.55Mn2O4·1.5H2O and K0.27MnO2·0.54H2O), cation-intercalated tungsten oxides (Li2WO4 and Na2W4O13), and anion-intercalated metal hydroxides (Zn5(OH)8(NO3)2·2H2O and Cu2(OH)3NO3), with a large lateral size and nanometre thickness in a short time. Using 2D Na2W4O13 as an electrode, a high performance electrochemical supercapacitor is achieved. We anticipate that our method will enable new path to the high-yield synthesis of 2D materials for applications in energy-related fields and beyond.

Birefringence and dichroism are very important properties in optical anisotropy. Understanding the intrinsic birefringence and dichroism of a material can provide great help to utilize its optical anisotropy. But the direct experimental investigation of birefringence in nanoscale materials is rarely reported. As typical anisotropic transition metals trichalcogenides (TMTCs) materials with quasi‐1D structure, TiS3 and ZrS3 have attracted extensive attention due to their special crystal structure and optical anisotropy characteristics. Here, the optical anisotropy properties such as birefringence and dichroism of two kinds of quasi‐1D TMTCs, TiS3 and ZrS3, are theoretically and experimentally studied. In experimental results, the anisotropic refraction and anisotropic reflection of TiS3 and ZrS3 are studied by polarization‐resolved optical microscopy and azimuth‐dependent reflectance difference microscopy, respectively. In addition, the birefringence and dichroism of ZrS3 nanoribbon in experiment are directly measured by spectrometric ellipsometry measurements, and a reasonable result is obtained. This work provides the basic optical anisotropy information of TiS3 and ZrS3. It lays a foundation for the further study of the optical anisotropy of these two materials and provides a feasible method for the study of birefringence and dichroism of other nanomaterials in the future.

Anisotropy in low-dimensional materials offers an extra degree of freedom to understand and tune the peculiar or potential properties to design novel electronic, optical, thermal, and optoelectronic devices. However, most research attention has been paid to qualitatively observing anisotropic phenomena, lacking quantitatively revealing optical anisotropy, in particular, and deeply digging for the physical mechanism. In this work, for the first time to our knowledge, the complete dielectric tensor of quasi-one-dimensional ZrTe5 is determined by Mueller matrix spectroscopic ellipsometry (MMSE) to quantitatively and comprehensively investigate the giant optical anisotropy, and the underlying physical mechanism is revealed by combination with the first-principle calculations. The ZrTe5 demonstrates giant dispersive birefringence and dichroism, and the birefringence (Δn = 0.58) outperforms many other low-dimensional and conventional birefringent materials, showing great potential and advantages in fabricating miniature and integrated polarization-sensitive devices. By combining the critical point (CP) analysis and first-principle calculations, the specific interband transitions related to the CPs in dielectric function spectra along three crystal axes of ZrTe5 are identified, revealing the physical essence of the optical anisotropy from the perspective of quantum mechanics. The proposed method is general and can be easily extended to quantitatively investigate the optical anisotropies in other novel low-symmetry materials.

Large-scale conducting polymer nanosheets (PPy, PANi and PEDOT) with tunable thicknesses and sizes have been successfully fabricated using CuCl2·2H2O salt as the oxidant and template via the vapor phase polymerization method.