Functionality Selection Principle for High Voltage Lithium-ion Battery Electrolyte Additives.

A new class of electrolyte additives based on cyclic fluorinated phosphate esters was rationally designed and identified as being able to stabilize the surface of a LiNiMnCoO (NMC532) cathode when cycled at potentials higher than 4.6 V vs Li/Li. Cyclic fluorinated phosphates were designed to incorporate functionalities of various existing additives to maximize their utilization.

Understanding the Role of Temperature and Cathode Composition on Interface and Bulk: Optimizing Aluminum Oxide Coatings for Li-Ion Cathodes.

Surface coating of cathode materials with AlO has been shown to be a promising method for cathode stabilization and improved cycling performance at high operating voltages. However, a detailed understanding on how coating process and cathode composition change the chemical composition, morphology, and distribution of coating within the cathode interface and bulk lattice is still missing. In this study, we use a wet-chemical method to synthesize a series of AlO-coated LiNiCoMnO and LiCoO cathodes treated under various annealing temperatures and a combination of structural characterization techniques to understand the composition, homogeneity, and morphology of the coating layer and the bulk cathode.

Mechanistic Insight in the Function of Phosphite Additives for Protection of LiNi0.5Co0.2Mn0.3O2 Cathode in High Voltage Li-Ion Cells.

Triethlylphosphite (TEP) and tris(2,2,2-trifluoroethyl) phosphite (TTFP) have been evaluated as electrolyte additives for high-voltage Li-ion battery cells using a Ni-rich layered cathode material LiNi0.5Co0.2Mn0.

Time-Dependent Solid State Polymorphism of a Series of Donor-Acceptor Dyads.

In order to exploit the use of favorable electrostatic interactions between aromatic units in directing the assembly of donor-acceptor (D-A) dyads, the present work examines the ability of conjugated aromatic D-A dyads with symmetric side chains to exhibit solid-state polymorphism as a function of time during the solid formation process. Four such dyads were synthesized and their packing in the solid-state from either slower (10-20 days) or faster (1-2 days) evaporation from solvent was investigated using single crystal X-ray analysis and powder X-ray diffraction. Two of the dyads exhibited tail-to-tail (A-A) packing upon slower evaporation from solvent and head-to-tail (D-A) packing upon faster evaporation from solvent.

More than meets the eye: conformational switching of a stacked dialkoxynaphthalene-naphthalenetetracarboxylic diimide (DAN-NDI) foldamer to an NDI-NDI fibril aggregate.

The thermally induced conformational switching of a stacked dialkxoynaphthalene-naphthalenetetracarboxylic diimide (DAN-NDI) amphiphilic foldamer to an NDI-NDI fibril aggregate is described. The aggregated fibril structures were explored by UV/Vis, circular dichroism (CD), atomic-force microscopy (AFM), and TEM techniques. Our findings indicate that the aromatic DAN-NDI interactions of the original foldamer undergoes transformation to a fibrillar assembly with aromatic NDI-NDI stacked interactions.