Synthesis of Sub-10 nm Two-Dimensional Covalent Organic Thin Film with Sharp Molecular Sieving Nanofiltration.

We demonstrated here a novel and facile synthesis of two-dimensional (2D) covalent organic thin film with pore size around 1.5 nm using a planar, amphiphilic and substituted heptacyclic truxene based triamine and a simple dialdehyde as building blocks by dynamic imine bond formation at the air/water interface using Langmuir-Blodgett (LB) method. Optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM), all unanimously showed the formation of large, molecularly thin and free-standing membrane that can be easily transferred on different substrate surfaces. The 2D membrane supported on a porous polysulfone showed a rejection rate of 64 and 71% for NaCl and MgSO4, respectively, and a clear molecular sieving at molecular size around 1.3 nm, which demonstrated a great potential in the application of pretreatment of seawater desalination and separation of organic molecules.

Surface modification of sulfur electrodes by chemically anchored cross-linked polymer coating for lithium-sulfur batteries.

Lithium-sulfur batteries suffer from severe self-discharge due to polysulfide dissolution into electrolytes. In this work, a chemically anchored polymer-coated (CAPC) sulfur electrode was prepared, through chemical bonding by coordinated Cu ions and cross-linking, to improve cyclability for Li/S batteries. This electrode retained specific capacities greater than 665 mAh g(-1) at high current density of 3.35 A g(-1) (2C rate) after 100 cycles with an excellent Coulombic efficiency of 100%.