The confinement and high utilization of sulfur in the cathodes is critical for improved cycling performance of lithium-sulfur batteries. In this case one-pot hydrothermal strategy is developed to produce rGO/MXene/sulfur composite aerogels where sulfur is in situ trapped in the 3D rGO/MXene conductive skeleton. The optimized composite aerogels as free-standing cathodes delivery a specific capacity of 951 mAhg-1 after 100 cycles at 0.2 C with a low fading rate of 0.062 % per cycle. The excellent cycling performance is correlated with highly oxidized MXene and in situ formed sulfate/thiosulfate complex layer in the long-term cycles.

The aim of this study was to achieve rapid gelation of chitosan (CS) and silica (SA) without crosslinking agent, the relationship between process parameters and the composite aerogels properties were also explored. By varying the composition ratio of the system (from SA:CS = 1:1 to 5:1), the system gelation time was reduced by >12 times, and the drying shrinkage of the composite aerogel reached a minimum of 7.6 %. During the two recombination processes, chitosan rapidly formed aqueous colloid secondary structure under the influence of ethanol. This phenomenon reduced the stability of the system and allowed silica to form a two-phase composite hydrogel. Because the network gap between the fibers was used as a limiting medium for gel growth. In addition, the chitosan/silica composite aerogels exhibited a mesoporous structure with low density (0.1144 g/cm3), and the thermal conductivity was 0.028 W/(m·K) at 30 °C. The trimethylchlorosilane made the composite aerogel have good hydrophobicity with water contact angle as 134.7°, and the adsorption capacity of carbon tetrachloride could reach >10 times of its own weight. This study provides an eco-friendly and high-efficiency method for preparing aerogels, which has potential applications in the fields of thermal insulation, oil-water separation, etc.

In this work, carboxylated and amination modified cellulose nanofibrils (CNFs) were fabricated via the TEMPO catalytic oxidation system and diethylenetriamine, and collagen composite aerogels were fabricated through a simple self-assembly pretreatment and directional freeze-drying technology. Morphology analysis showed that the collagen composite aerogels had distinct layered-oriented double network structures after the self-assembly pretreatment. The intermolecular interactions between the collagen fibrils and functionalized CNFs (fCNFs) on the structures and properties of the composite aerogels were also examined through various characterization techniques. Water contact angle tests demonstrated the pH-responsive characteristics of the collagen/fCNF composite aerogels. Using 5-fluorouracil as the model drug, the pH-response mechanism was revealed. These results indicated that the collagen/fCNF composite aerogels exhibited excellent pH-responsive drug release capacities. Therefore, these pH-responsive collagen composite aerogels might have potential applications in industrial production in the biomedical, drug delivery, and tissue engineering fields.

Aerogels are a class of advanced materials having the lowest density with extraordinary characteristics of high surface area, extreme porosity, lowest thermal conductivity, and tunable surface chemistry. Aerogels of silica, alumina, carbon, metals, metal oxides, clay, cellulose, gelatin, chitosan, synthetic polymers and many others have attracted much interest for different potential applications. Several attempts have been made to improve the characteristics and performance efficiency of the aerogels. One of those is to fabricate composite aerogels to be used in several applications. In designing composite aerogels for biomedical and environmental purposes, the nature of the ingredient materials along with their net efficiency and cost are important to be considered. In this regard, various compositions of composite aerogels have been explored by researchers to make them suitable for use in these applications. In the present study, an attempt has been made to briefly summarize various studies of composite aerogels for biomedical and environmental applications.