Carbon nanofiber (CNF), as one of the most important members of carbon fibers, has been investigated in both fundamental scientific research and practical applications. CNF composites are able to be applied as promising materials in many fields, such as electrical devices, electrode materials for batteries and supercapacitors and as sensors. In these applications, the electrical conductivity is always the first priority need to be considered. In fact, the electrical property of CNF composites largely counts on the dispersion and percolation status of CNFs in matrix materials. In this review, the electrical transport phenomenon of CNF composites is systematically summarized based on percolation theory. The effects of the aspect ratio, percolation backbone structure and fractal characteristics of CNFs and the non-universality of the percolation critical exponents on the electrical properties are systematically reviewed. Apart from the electrical property, the thermal conductivity and mechanical properties of CNF composites are briefly reviewed, as well. In addition, the preparation methods of CNFs, including catalytic chemical vapor deposition growth and electrospinning, and the preparation methods of CNF composites, including the melt mixing and solution process, are briefly introduced. Finally, their applications as sensors and electrode materials are described in this review article.

It is crucial to align two-dimensional nanosheets to form a highly compact layered structure for many applications, such as electronics, optoelectronics, thermal management, energy storage, separation membranes, and composites. Here we show that continuous centrifugal casting is a universal, scalable and efficient method to produce highly aligned and compact two-dimensional nanosheets films with record performances. The synthesis  mechanism, structure  control and property  dependence of alignment and compaction of the films are discussed. Significantly, 10-μm-thick graphene oxide films can be synthesized within 1 min, and scalable synthesis of meter-scale films is demonstrated. The reduced graphene oxide films show super-high strength (~660 MPa) and conductivity (~650 S cm−1). The reduced graphene oxide/carbon nanotube hybrid-film-based all-solid-state flexible supercapacitors exhibit ultrahigh volumetric capacitance (407 F cm−3) and energy density (~10 mWh cm−3) comparable to that of thin-film lithium batteries. We also demonstrate the production of highly anisotropic graphene nanocomposites as well as aligned, compact films and vertical heterostructures of various nanosheets.

We discovered that attenuated Salmonella after intravenous injection would proliferate within various types of solid tumors but show rapid clearance in normal organs, without rendering notable toxicity. Bacteria-induced inflammation would trigger thrombosis in the infected tumors by destroying tumor blood vessels. Six types of tested tumors would all turn into darkened color with strong near-infrared absorbance, as observed by photoacoustic imaging. Under laser irradiation, those bacterial-infected tumors would be effectively ablated. Because of the immune-stimulation function, such bacteria-based photothermal therapy (PTT) would subsequently trigger antitumor immune responses, which could be further enhanced by immune checkpoint blockade to effectively suppress the growth of abscopal tumors. A robust immune memory effect to reject rechallenged tumors is also observed after bacteria-based PTT. Our work demonstrates that bacteria by themselves could act as a tumor-specific PTT agent to enable photoimmunotherapy cancer therapy to inhibit tumor metastasis and recurrence.

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