超低密度的SiO₂气凝胶是一种经典的三维网状纳米多孔材料，已经广泛应用于如保温隔热、吸附等多种领域。以四甲氧基硅烷（TMOS）为硅源，采用酸碱两步法，利用乙醇超临界干燥技术制备了超低密度的SiO₂气凝胶，分别利用SEM\TEM\BET等表征手段对该气凝胶进行了一系列的研究，发现当其密度为0.6 mg/cm³时，气凝胶拥有最佳的综合性能。该种气凝胶具有超低密度、高比表面积、加工成型性好、制备周期短等优点，有望在激光惯性约束聚变实验中作为冷冻靶发挥巨大的作用。

Ultra-low density SiO₂ aerogel as a classic three-dimensional network nano-porous material is widely used in many fields such as thermal insulation and adsorption. In this manuscript, tetramethoxysilane (TMOS) is used as the silicon source and an acid-base two-step method is used. Ultra-low density SiO₂ aerogels were prepared by ethanol supercritical drying technology, and a series of studies were performed on the aerogels using SEM\TEM\BET and other characterization methods. When the aerogel density was 0.6 mg/cm³, it had the best comprehensive properties. In addition, this aerogel has the advantages of ultra-low density, high specific surface area, good formability, and short preparation cycle. Thus, it is expected to play a significant role as a frozen target in laser inertial confinement fusion experiments.