Abstract As a unique tubular nanoclay, halloysite nanotubes (HNTs) have recently attracted significant research attention. The HNTs have outer diameters of ∼50 nm, inner lumens of ∼20 nm and are 200–1000 nm long. They are biocompatible nanomaterials and widely available in nature, which makes them good candidates for application in biomedicine. Compared with other types of nanoparticles such as polymer nanoparticles and carbon nanotubes, the drawbacks associated with HNTs include brittleness, difficulty with fabrication, low fracture strength, high density and inadequate biocompatibility. Preparation of polysaccharide-HNT composites offer a means to overcome these shortcomings. Halloysite nanotubes can be incorporated easily into polysaccharides via solution mixing, such as with chitosan (CS), sodium alginate, cellulose, pectin and amylose, for forming composite films, porous scaffolds or hydrogels. The interfacial interactions, such as electrostatic attraction and hydrogen bonding, between HNTs and the polysaccharides are critical for improvement of the properties. Morphology results show that HNTs are dispersed uniformly in the composites. The mechanical strength and Young's modulus of the composites in both the dry and wet states are enhanced by HNTs and the HNTs can also increase the storage modulus, glass-transition temperature and thermal stability of the composites. Cytocompatibility results demonstrate that the polysaccharide-HNT composites have low cytotoxicity even for HNT loading >80%. Therefore, the polysaccharide-HNT composites show great potential for biomedical applications, e.g. as tissue engineering scaffold materials, wound-dressing materials, drug-delivery carriers, and cell-isolation surfaces.
Abstract High‐power lithium‐ion batteries (LIBs) are critical for power‐intensive applications; however, their development is largely hindered by the lack of anode materials that have stability and high capacity at high charging/discharging rates. Herein, a cationic disordering strategy is reported to build an ideal high‐power anode with boosted intercalation kinetics and a stable framework. A novel titanium niobate (TiNb 2 O 7 ) anode with unique predistorted Nb(Ti)O 6 octahedrons (pd‐TNO) is developed by introducing cation disorder, which allows ultrafast Li + storage within seconds and exceptional stability over long cycling at high rates. The pd‐TNO delivers an outstanding specific capacity of 153 mAh g −1 at 100 C, 20 times higher than that of conventional TNO anodes without cationic disordering, and retains 42.8% of the capacity after 15,000 cycles. Using the pd‐TNO anode, a high‐power LIB with an unprecedented power density of 91,197 W kg −1 at 200 C, which is approximately eight times higher than that of the advanced commercial high‐power anode Li 4 Ti 5 O 12 (11,813 W kg −1 at 50 C), is demonstrated. Importantly, the pd‐TNO is prepared under ambient conditions via a high‐throughput process, and it exhibits considerable potential for scalability for practical applications.
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