Kohlenstoffnanofaser-Aerogele: Vergleich von Chemosynthese und Biosynthese

Self-Assembled Dipeptide Aerogels with Tunable Wettability

Constructing supramolecular materials with tunable properties and functions is a great challenge due to the complex competition between multiple assembly pathways. Herein, we report that dipeptides can self-assemble into aerogels with entirely different surface wettability through precisely controlling the assembly pathways. Charged groups or aromatic residues are selectively exposed on the surface of their nanoscale building blocks which results either in a superhydrophilic or highly hydrophobic surface. With this special property, single component dipeptide aerogels can play diverse roles in medical care applications. This study suggests great promise in the synthesis of supramolecular materials with different targeted functions from the same molecular unit.

Fabrication of highly pressure-sensitive, hydrophobic, and flexible 3D carbon nanofiber networks by electrospinning for human physiological signal monitoring

Three-dimensional (3D) porous nanostructure materials have promising applications in pressure sensors or other situations. However, the low sensing sensitivity of these materials restricts precise detection of physiological signals, and it is still a challenge to manufacture highly pressure-sensitive materials, which simultaneously possess other versatile properties. Herein, a simple and cost-efficient strategy is proposed to fabricate versatile 3D carbon nanofiber networks (CNFNs) with superior pressure-sensitivity through electrospinning and thermal treatment. The pressure sensitivity of the CNFNs is 1.41 kPa-1, which is much higher than that of similar 3D porous materials. Unlike traditional carbonaceous materials, the CNFNs exhibit excellent flexibility, stable resilience, and super compressibility (>95%), because of the nano-reinforce of Al2O3. Benefiting from the robust mechanical and piezoresistive properties of the CNFNs, a pressure sensor designed with the CNFNs is able to monitor human physiological signals, such as phonation, pulse, respiration and human activities. An arch-array platform for direction identification of tangential forces and an artificial electronic skin bioinspired by human's hairy skin have been ingeniously designed. The CNFNs also present other versatile characteristics as well, including ultralight density, hydrophobicity, low thermal conductivity, and low infrared emissivity. Therefore, the CNFNs have promising potential in a wide range of applications.

Bacterial-Derived, Compressible, and Hierarchical Porous Carbon for High-Performance Potassium-Ion Batteries

Hierarchical-structured electrodes having merits of superior cycling stability and high rate performance are highly desired for next-generation energy storage. For the first time, we reported a compressible and hierarchical porous carbon nanofiber foam (CNFF) derived from a sustainable and abundant biomaterial resource, bacterial cellulose, for boosting the electrochemical performance of potassium-ion batteries. The CNFF free-standing electrode with a hierarchical porous three-dimensional structure demonstrated excellent rate performance and outstanding cyclic stability in the extended cycling test. Specifically, in the long-term cycling-stability test, the CNFF electrode maintained a stable capacity of 158 mA h g^-1 after 2000 cycles at a high current density of 1000 mA g^-1, which has an average capacity decay of 0.006% per cycle. After that, the CNFF electrode maintained a capacity of 141 mA h g^-1 at a current density of 2000 mA g^-1 for another 1500 cycles, and a capacity of 122 mA h g^-1 at a current density of 5000 mA g^-1 for an additional 1000 cycles. The mechanism for the outstanding performance is that the hierarchical porous and stable CNFF with high surface area and high electronic conductivity provides sufficient sites for potassium-ion storage. Furthermore, quantitative kinetics analysis has validated the capacitive- and diffusion-controlled charge-storage contributions in the carbon-foam electrode. This work will inspire the search for cost-effective and sustainable materials for potassium electrochemical energy storage.