A dual-functional polymer coating on a lithium anode for suppressing dendrite growth and polysulfide shuttling in Li-S batteries.

A surface coating that simultaneously suppressed Li dendrite growth and polysulfide shuttling on a lithium anode was successfully developed using a polymer blend composed of Nafion® and polyvinylidene difluoride (PVDF). This hierarchically nanostructured composite coating efficiently alleviated the swelling and dissolution problems of cation-selective Nafion® in the electrolyte and provided sufficient mechanical strength to accommodate large volumetric variations in the Li anode during charge-discharge cycles. The Nafion®/PVDF-coated Li anode exhibited substantially enhanced rate performance and cyclability as well as improved Coulombic efficiency for Li-S prototype batteries with a high-S-content cathode.

Mass-transport Control on the Discharge Mechanism in Li-O2 Batteries Using Carbon Cathodes with Varied Porosity.

By comparing carbon electrodes with varying porosity in Li-O2 cells, we show that the effect of electrolyte stirring at a given current density can result in a change from 2D to 3D growth of discharged deposits. The change of morphology is evident using electron microscopy and by analyzing electrode pore size distribution with respect to discharge capacity. As a consequence, carbon electrodes with different textural properties exhibit different capacity enhancements in stirred-electrolyte cells.

Spatial Distributions of Discharged Products of Lithium-Oxygen Batteries Revealed by Synchrotron X-ray Transmission Microscopy.

The discharge products of ether-based Li-O2 cells were grown directly on common carbon-coated TEM grids and observed by oxidation-state-sensitive full field transmission soft X-ray microscopy (TXM). The acquired data have permitted to quantify and localize with spatial resolution the distribution of the oxygen discharge products in these samples (i.e.