To provide adequate conditions for the regeneration of damaged bone, it is necessary to develop piezoelectric porous membranes with antioxidant and anti-inflammatory activities. In this study, composite nanofibers comprising poly(vinylidene fluoride) (PVDF) and a polyhedral oligomeric silsesquioxane–epigallocatechin gallate (POSS–EGCG) conjugate were fabricated by electrospinning methods. The resulting composite nanofibers showed three-dimensionally interconnected porous structures. Their average diameters, ranging from 936 ± 223 nm to 1094 ± 394 nm, were hardly affected by the addition of the POSS–EGCG conjugate. On the other hand, the piezoelectric β-phase increased significantly from 77.4% to 88.1% after adding the POSS–EGCG conjugate. The mechanical strength of the composite nanofibers was ameliorated by the addition of the POSS–EGCG conjugate. The results of in vitro bioactivity tests exhibited that the proliferation and differentiation of osteoblasts (MC3T3-E1) on the nanofibers increased with the content of POSS–EGCG conjugate because of the improved piezoelectricity and antioxidant and anti-inflammatory properties of the nanofibers. All results could suggest that the PVDF composite nanofibers were effective for guided bone regeneration.

Metal–organic frameworks (MOFs) are porous materials assembled using metal and organic linkers, showing a high specific surface area and a tunable pore size. Large portions of metal open sites in MOFs can be exposed to electrolyte ions, meaning they have high potential to be used as electrode materials in energy storage devices such as supercapacitors. Also, they can be easily converted into porous metal oxides by heat treatment. In this study, we obtained high energy storage performance by preparing electrode materials through applying heat treatment to manganese MOFs (Mn-MOFs) under air. The chemical and structural properties of synthesized and thermally treated Mn-MOFs were measured by Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The surface area and porosity were investigated by nitrogen adsorption/desorption isotherms. The electrochemical properties were studied by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) using a three-electrode cell. It was found that Mn-MOF electrodes that underwent heat treatment at 400 °C under air consisted of Mn₂O₃ with high specific surface area and porosity. They also showed a superior specific capacitance of 214.0 F g⁻¹ and an energy density value of 29.7 Wh kg⁻¹ (at 0.1 A g⁻¹) compared to non-treated Mn-MOFs.

Porous carbon nanofibers were prepared by electrospinning blend solutions of polybenzimidazole/poly-L-lactic acid (PBI/PLLA) and carbonization. During thermal treatment, PLLA was decomposed, resulting in the creation of pores in the carbon nanofibers. From SEM images, it is shown that carbon nanofibers had diameters in the range of 100–200 nm. The conversion of PBI to carbon was confirmed by Raman spectroscopy, and the surface area and pore volume of carbon nanofibers were determined using nitrogen adsorption/desorption analyses. To investigate electrochemical performances, coin-type cells were assembled using free-standing carbon nanofiber electrodes and ionic liquid electrolyte. cyclic voltammetry studies show that the PBI/PLLA-derived porous carbon nanofiber electrodes have higher capacitance due to lower electrochemical impedance compared to carbon nanofiber electrode from PBI only. These porous carbon nanofibers were activated using ammonia for further porosity improvement and annealed to remove the surface functional groups to better match the polarity of electrode and electrolyte. Ragone plots, correlating energy density with power density calculated from galvanostatic charge–discharge curves, reveal that activation/annealing further improves energy and power densities.

Porous carbon nanofibers (CNFs) with high energy storage performance were fabricated with a single precursor polymer, 6FDA-TFMB, without the use of any pore-generating materials. 6FDA-TFMB was synthesized, electrospun, and thermally treated to produce binder-free CNF electrodes for electrochemical double-layer capacitors (EDLCs). Highly porous CNFs with a surface area of 2213 m² g⁻¹ were prepared by steam-activation. CNFs derived from 6FDA-TFMB showed rectangular cyclic voltammograms with a specific capacitance of 292.3 F g⁻¹ at 10 mV s⁻¹. It was also seen that CNFs exhibit a maximum energy density of 13.1 Wh kg⁻¹ at 0.5 A g⁻¹ and power density of 1.7 kW kg⁻¹ at 5 A g⁻¹, which is significantly higher than those from the common precursor polymer, polyacrylonitrile (PAN).

MXenes consisting of thin layers of transition metal carbides or nitrides are good candidates for electrode materials due to their excellent electrical conductivity and fast ion transfer. Electrospun carbon nanofibers are highly porous and electrically conductive, making them attractive for electrode materials. In this study, free-standing electrodes were prepared by the dip-coating of carbon nanofibers (CNFs) in the MXene (Ti₃C₂) colloidal solution, which was synthesized via the wet-etching of MAX (Ti₃AlC₂) phase, and their chemical structures were investigated by X-ray diffraction and Fourier transform infrared spectroscopy. In addition, scanning and transmission electron microscopy were used to investigate the morphological and crystallographic features of MXene-coated CNFs. Surface area and pore volumes were investigated by nitrogen adsorption/desorption measurements. Supercapacitor performance was studied by assembling a 3-electrode system with 1M aqueous sodium sulfate solution as an electrolyte. MXene-coated CNFs exhibited a maximum specific capacitance of 514 F/g at 0.5 A/g, with energy and power densities of 71.4 Wh/kg at 0.5 A/g and 2.3 kW/kg at 5 A/g, respectively, which are relevantly higher compared to the pristine CNFs due to the pseudocapacitive behavior of MXenes. They also showed comparable cyclic stability during 5000 cycles with the CNFs. This result indicates that MXene-coated carbon nanofibers can be effective electrode materials for electrochemical energy storage.

Highly porous carbon electrodes for supercapacitors with high energy storage performance were prepared by using a new precursor blend of aromatic polyimide (PI) and polyvinylidene fluoride (PVDF). Supercapacitor electrodes were prepared through the electrospinning and thermal treatment of the precursor blends of aromatic PI and PVDF. Microstructures of the carbonized PI/PVDF nanofibers were studied using Raman spectroscopy. Nitrogen adsorption/desorption measurements confirmed their high surface area and porosity, which is critical for supercapacitor performance. Energy storage performance was investigated and carbonized PI/PVDF showed a high specific capacitance of 283 F/g at 10 mV/s (37% higher than that of PI) and an energy density of 11.3 Wh/kg at 0.5 A/g (27% higher than that of PI) with high cycling stability.