In terms of the drying process, supercritical drying is one classical method and the most effective method to obtain complete structure aerogel. ‘Its principle is through high temperature and high pressure to make the drying medium reach supercritical state, eliminate the gas liquid interface. Meanwhile, this method effectively avoids the occurrence of surface tension, and maintains the good performance of the gel. The most commonly used media are ethanol alcohol and carbon dioxide.’[1]