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It is an effective way to develop basswood (Tilia americana, hardwood)-derived thick carbon electrode for high energy density supercapacitors. The wood-derived anisotropic structural carbon electrodes have different transfer kinetics of the electrolyte, which will significantly affect the electrochemical performance especially at high current density. Therefore, the relationship between the sectional wood-derived electrodes and the electrochemical performance of supercapacitors were systematically studied. The results show that the high specific surface area (542 m2 g−1) of cross-sectional wood-derived carbon contributes to the excellent electrochemical performance (specific/area capacitance ~ 3040 mF cm−2/118 F g−1 at 1 mA cm−2, cycle stability ~ 82.2% after 10,000 cycles at 50 mA cm−2, and capacitive contribution of 76.64% at 5 mV s−1), which is attributed to the hierarchical porous structure and easily allows electrolytes to enter the interior even at high current density. This work provides a fundamental understanding of the dynamic behaviors of electrolyte at different wood sections, and it is expected to be extended to other wood species and wood-like structures for energy storage applications. [ABSTRACT FROM AUTHOR]

Flexible all-organic dielectric materials are highly required for miscellaneous applications in modern flexible electronics and energy storage devices but are often hindered by the poor mechanical performance, especially the poor toughness. In this work, because of the special chemical structures and properties, β-cyclodextrin (β-CD) was used to toughen the polyimide (PI) matrix and improve the dielectric properties. Dynamic mechanical analysis (DMA) indicated that β-CD was miscible with PI matrix. The obtained PI/β-CD composite films exhibited a high dielectric permittivity of 8.11, breakdown strength of 217 MV/m, maximum energy density of 1.46 J/cm, tensile strength > 160 MPa, toughness > 56 J/g, T > 300 °C and T > 280 °C, which are much better than other all-organic dielectric materials, such as PVDF and its derivatives. These PI/β-CD composite films would be promising materials for all-organic film capacitors. [ABSTRACT FROM AUTHOR]