Preparation and textural evolution: From organosilane aerogel to SiOC aerogels

Generally, SiOC aerogels are prepared utilizing the high-temperature pyrolysis of polyorganosiloxanes or polycarboorganosilanes in an inert gas atmosphere. However, the crosslinking and drying of the precursor rely on the catalysts of noble metal, the equipment of autoclave, and the technology of supercritical drying, which limit the batch production of SiOC aerogel. In this work, the SiOC aerogels were prepared via pyrolysis of methyltrimethoxysilane/triethoxyvinylsilane (MTMS/VTES) organosilane aerogel precursor (O-SAP), which was synthesized using sol-gel method and ambient pressure drying technology. Under the temperature of 1500 °C, the SiOC aerogel exhibited excellent properties with high porosity (80%), high compressive strength (11.52 MPa), and low thermal conductivity (0.08 W m K−1), which overweighed most state-of-the-art SiOC aerogels. More significantly, a new concept of “gases truing” was firstly proposed to explain the microstructure evolution of O-SAP during pyrolysis. This paper is expected to provide insights for the preparation of high-performance SiOC aerogels, with promising applications in heat insulation and anode material of Li-ion battery.