Conducting polymer‐based organic electrochemical capacitor materials have attracted attention because of their highly conductive nature and highly reversible redox reactions on the surface of electrodes. However, owing to their poor stabilities in aprotic electrolytes, alternative organic electrochemical capacitive electrodes are being actively sought. Here, fluorine atoms are introduced into contorted hexabenzocoronene (cHBC) to achieve the first small‐molecule‐based organic capacitive energy‐storage cells that operate at high current rates with satisfactory specific capacities of ≈160 mA h g−1 and superior cycle capabilities (>400) without changing significantly. This high capacitive behavior in the P21/c crystal phase of fluorinated cHBC (FcHBC) is caused mainly by the fluorine atoms at the end of each peripheral aromatic ring. Combined Monte Carlo simulations and density functional theory (DFT) calculations show that the most electronegative fluorine atoms accelerate ion diffusion on the surface to promote fast Li+ ion uptake and release by an applied current. Moreover, FcHBC has potential applications as the capacitive anode in Na‐ion storage cells. The fast dynamics of its capacitive behavior allow it to deliver a specific capacity of 65 mA h g−1 at a high current of 4000 mA g−1.
Commercially available boron nitride nanotubes (BNNTs) and their purified form (pBNNTs) were dispersed in aqueous solutions with various dispersants, and their cytotoxicity and drug encapsulation capacity were monitored. Our data suggest that pBNNTs showed an average increase in dispersibility of 37.3% in aqueous solution in the presence of 10 different dispersants. In addition, 100 μg of pBNNTs induced an average decrease in cytotoxicity of 27.4% compared to same amount of BNNTs in normal cell lines. The same amount of pBNNTs can encapsulate 10.4-fold more drug (camptothecin) compared to BNNTs. These data suggest that the purification of BNNTs improves several of their properties, which can be applied to biological experiments and are thus essential in the biological application of BNNTs.
Enhancing the performance of carbon-based anode materials in Li-ion battery (LIB) systems is of considerable interest in terms of next-generation LIB host electrodes, because the unique reversible intercalation–de-intercalation process of such materials ultimately facilitates increases in LIB performance and longevity. This study explored the potential of a new class of carbon-based contorted hexabenzocoronene (c-HBC) as an anode material for high-performance LIB systems. The exploitation of the polymorphic crystalline nature of c-HBC resulted in successful development of a LIB anode based on a newly found crystal phase of trigonal R by solvent and subsequent thermal annealing. Our in-depth analysis based on cross-sectional transmission electron microscopy, grazing incidence X-ray diffraction, and computational investigation revealed further advantages of using contorted molecules in LIB systems. For instance, the resulting electrochemical characteristics using half-cell architecture clearly reflected single-stage Li insertion behavior associated with the large interspacing and short diffusion length of c-HBC molecule during the discharging process. In addition, the battery exhibited excellent rate capability and cycle endurance, highlighting the suitability of c-HBC as an anode material for high-performance LIBs.