A general and efficient solvothermal strategy has been developed for the preparation of lithium transition metal phosphate microstructures (LiMnPO4, LiFePO4, and LiCoPO4), employing ethanol as the solvent, LiI as the Li source, metal salts as the M sources, H3PO4 as the phosphorus source, and poly(vinyl pyrrolidone) (PVP) as the carbon source and template. This route features low cost, environmental benign, and one-step process for the cathode material production of Li-ion batteries without any complicated experimental setups and sophisticated operations. The as-synthesized LiMPO4 microstructures exhibit unique, well-shaped and favorable structures, which are self-assembled from microplates or microrods. The b axis is the preferred crystal growth orientation of the products, resulting in a shorter lithium ion diffusion path. The LiFePO4 microstructures show an excellent cycling stability without capacity fading up to 50 cycles when they are used as a cathode material in lithium-ion batteries. 相似文献
The recent work of the authors on the novel sol-enhanced nano-composite coatings was reviewed.This technique was developed to create high dispersion of oxide nano-particles into metal/alloy coatings.The agglomeration of nano-particles in the traditional composite coatings prepared by solid-powder mixing methods can be effectively avoided.Correspondingly the mierostructures of the sol-enhanced coatings are very different from those of the conventional composite coatings,and the coatings show superior mech... 相似文献
Multiwalled, bamboo-like carbon nanotube (BCNT)/methyl vinyl silicone (MVQ) composites with different concentrations of BCNT were fabricated by liquid blending method with an aim to investigate the behavior of such composites as effective electromagnetic interference shielding material in the frequency range of 1–6?GHz. The morphology and structure of BCNT were characterized and elucidated. Scanning electron microscopy examination showed that the BCNTs homogeneously dispersed in MVQ. The electrical conductivity (σ) and shielding effectiveness (SE) of the composite were measured and discussed. The results showed that the BCNTs/MVQ composites had a relatively low percolation threshold at 0.92?wt. % BCNT, and the σ showed a decreasing linear relation with temperature, i.e., the σ slightly decreased with increasing temperature. The BCNTs/MVQ composites with SE of 33–38?dB were obtained at 7?wt. % BCNT loading. Shielding mechanism was studied by resolving the total incident energy into absorbed, reflected, and transmitted contribution, and the result showed that the dominated shielding mechanism was reflection loss. 相似文献
Amorphous metal–organic frameworks (amMOFs) with a partially collapsed structure are a new category of porous hybrid materials. Here, solid-state amorphization of ZIF-8 was achieved by mechanical compression at 0.75 GPa. The compression-induced amorphous ZIF-8 (amZIF-8) had a collapsed structure, but retained partial porosity. Benefiting from the deformed channel, the resultant amZIF-8 exhibited preferable adsorption of C3H6, resulting in higher thermodynamic adsorption selectivity of C3H6/C3H8 (6.72) than the crystalline counterparts (1.06). Further, amZIF-8 achieved complete separation of an equimolar C3H6/C3H8 mixture with the first breakthrough of C3H8. amZIF-8 also displayed an enhancement in CO2/N2 and CO2/CH4 adsorption selectivities. More importantly, a self-standing amZIF-8 membrane with boundary-free microstructure was constructed for the first time, and exhibited separation potential for H2/CH4, CO2/N2, CO2/CH4, and C3H6/C3H8 with ideal selectivities of 14.79, 12.83, 16.23, and 2.67, respectively. 相似文献
3‐D rose‐like microstructures of polyaniline (PANI), which are self‐assembled from 2‐D nanosheets consisted of 1‐D nanofibers, were synthesized by a template‐free method in the presence of ammonium peroxydisulfate (APS) as both oxidant and dopant under a high relative humidity of 80% for the first time. When the relative humidity increases from 25 to 80%, not only morphology of the micro/nanostructured PANI undergoes a change from 1‐D nanofibers to 2‐D nanosheets to 3‐D rose‐like microstructures, but also increase in crystallinity. It is proposed that a cooperation effect of the oriented water molecules at the vapor–water interface and difference in hydrogen bonding energies between the interface and the bulk induced by the relative high humidity results in the formation of the 3‐D rose‐like microstructures self‐assembled from 2‐D nanosheets. Moreover, the method reported may provide a simple approach for understanding self‐assembly of complex micro/nanostructures of PANI.