Browsing by Author "Soliman, Ahmed B."

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Carbon Aerogels Derived from Anion-Modified Nanocellulose for Adaptive Supercapacitor Performance
(2024-07-10) Al Haj, Yazan; Soliman, Ahmed B.; Vapaavuori, Jaana; Elbahri, Mady
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
In the pursuit of developing advanced carbon aerogel (CA) supercapacitors, a rational design approach is introduced that utilizes often overlooked conjugated anions to modulate the properties of CAs. Ionic cross-linking of cellulose nanocrystal (CNC) aerogels ensures the preservation of structural integrity even after carbonization. Interestingly, anion selection not only influences the cross-linking and carbonization processes but also significantly modulates the electrochemical performance of the resulting CAs. This is found to be vital in optimizing the overall supercapacitor performance. Electro-assisted (EA) wetting of the electrodes procures an adaptive and progressive performance enhancement, heralding the advent of sustainable supercapacitors crafted from earth-abundant materials.
Microporous MOF as nanogen facilitating diffusion-coupled charge transfer near the percolation threshold in a polyaniline pseudo-supercapacitor
(2022-01-07) El-Mehalmey, Worood A.; Haikal, Rana R.; Ali, Aya Mohamed; Soliman, Ahmed B.; ElBahri, Mady; Alkordi, Mohamed H.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Several approaches have recently been investigated with the aim of enhancing the specific capacitance of polyaniline (PANI). We herein report a novel pathway to boost the specific capacitance of PANI, which is highly tunable and versatile, based on wet chemistry techniques. In this approach, utilization of a specific metal-organic framework (MOF), UiO-66-NH2, as a nanopore generator (Nanogen) is demonstrated. This systematic study demonstrates a tight interplay between the enhanced electrolyte accessibility to the PANI chains, through the incorporation of MOF nanogens, and the optimal relative amount of the conductive PANI, necessary to attain a charge percolation threshold in the binary system (MOF@PANI). Satisfying the charge percolation while maintaining porosity is necessary to arrive at a maximized specific capacitance of the PANI as the active phase. The enhancement in the specific capacitance of the PANI was fully exploited through a systematic investigation that helped to pinpoint the saddle point at which the two orthogonal properties, namely porosity (electrolyte diffusivity) and charge mobility (PANI inter-chain electronic conductivity) can be fine-tuned via controlling the materials composition. Of the different compositions investigated, the composite containing 23 wt% PANI of the total weight, doped with MOF nanogens, resulted in an enhanced specific capacitance of 872 F g-1 for the PANI, in comparison to only 469 F g-1 for the pristine PANI investigated under identical conditions.