Polymer-Derived Ceramic Nanoparticle/Edge-Functionalized Graphene Oxide Composites for Lithium-Ion Storage.

Polymer-derived ceramics demonstrate great potential as lithium-ion battery anode materials with good cycling stability and large capacity. SiCNO ceramic nanoparticles are produced by the pyrolysis of polysilazane nanoparticles that are synthesized via an oil-in-oil emulsion crosslinking and used as anode materials. The SiCNO nanoparticles have an average particle size of around 9 nm and contain graphitic carbon and Si3N4 and SiO2 domains. Composite anodes are produced by mixing different concentrations of SiCNO nanoparticles, edge-functionalized graphene oxide, polyvinylidenefluoride, and carbon black Super P. The electrochemical behavior of the anode is investigated to evaluate the Li-ion storage performance of the composite anode and understand the mechanism of Li-ion storage. The lithiation of SiCNO is observed at ∼0.385 V versus Li/Li+. The anode has a large capacity of 705 mA h g-1 after 350 cycles at a current density of 0.1 A g-1 and shows an excellent cyclic stability with a capacity decay of 0.049 mA h g-1 (0.0097%) per cycle. SiCNO nanoparticles provide a large specific area that is beneficial to Li+ storage and cyclic stability. In situ transmission electron microscopy analysis demonstrates that the SiCNO nanoparticles exhibit extraordinary structural stability with 9.36% linear expansion in the lithiation process. The X-ray diffraction and X-ray photoelectron spectroscopy investigation of the working electrode before and after cycling suggests that Li+ was stored through two pathways in SiCNO lithiation: (a) Li-ion intercalation of graphitic carbon in free carbon domains and (b) lithiation of the SiO2 and Si3N4 domains through a two-stage process.

Nanomaterials in Advanced, High-Performance Aerogel Composites: A Review.

Aerogels are one of the most interesting materials of the 21st century owing to their high porosity, low density, and large available surface area. Historically, aerogels have been used for highly efficient insulation and niche applications, such as interstellar particle capture. Recently, aerogels have made their way into the composite universe. By coupling nanomaterial with a variety of matrix materials, lightweight, high-performance composite aerogels have been developed for applications ranging from lithium-ion batteries to tissue engineering materials. In this paper, the current status of aerogel composites based on nanomaterials is reviewed and their application in environmental remediation, energy storage, controlled drug delivery, tissue engineering, and biosensing are discussed.