To analyze powder morphology, we employed field-emission scanning electron microscopy (FEI Magellan 400 XHR) in combination with an Everhart-Thornley detector. Powders were suspended in isopropyl alcohol (> 99.5%, Fisher Chemical) and, to prevent settling of the suspension, were drop cast within one min onto Al foil adhered to a stub with conductive silver paint (Ted Pella).