Yazar "Ullah, Ghulam" seçeneğine göre listele

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    Nitrogen and sulfur-rich cobalt complex for hybrid supercapacitor applications
    (Elsevier, 2025) Saeed, Maham; Shah, Javed Hussain; Sharif, Shahzad; Shahbaz, Muhammad; Ullah, Ghulam; Shahzad, Ayesha; Sahin, Zarife Sibel
    In the quest for more effective and advanced energy storage devices, an integrated methodology combining both battery and supercapacitor hybrid features is being explored. In this regard, we have developed a cobalt-1,10-phenonthroline complex with 5-sulfoisopthalic acid in the lattice (Co-Phen@SIP) via sonication method. Structural properties were explored by Single-crystal XRD, Elemental analysis, TGA, FTIR, UV Visible and Fluorescence spectroscopy while detailed electrochemical study was carried out via CV, GCD and EIS. Three electrode setup revealed pseudocapacitive properties of Co-Phen@SIP with specific capacity of 157.6 Cg(-1) at 2 A g(-1). Battery-supercapacitor hybrid device showed energy density and power density of 13.03 Wh kg(-1) and 3309 W kg(-1) respectively. The device also exhibited remarkable columbic efficiency of 98.94 % even after 5000 GCD cycles. Theoretical approach based on Dunn's model and power law was also applied to check the capacitivediffusive contributions of three-electrode system and hybrid device. 1, 10-phenonthroline induces structural stability over long cyclability. The introduction of SIP in Co-complex caused charge transfer through pi center dot center dot center dot pi interactions providing porous and robust structure which aided in improved electric conductivity and ionic mobility. This multi-ligand chemistry with the redox active cobalt has achieved superior performance and reversibility in comparison to other traditional complexes. The idea came out to be an effective strategy for advanced hybrid supercapacitors.
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    Öğe
    Redox active cobalt based bi-linker metal organic frameworks derived from 5-sulfoisopthalic acid and 4,4-bipyridine for supercapacitor
    (Pergamon-Elsevier Science Ltd, 2025) Shah, Javed Hussain; Shahbaz, Muhammad; Sharif, Shahzad; Ullah, Ghulam; Shahzad, Sundas; Munawar, Khurram Shahzad; Sahin, Onur
    In this research study, we have synthesized, characterized and extensively compared the electrochemical characteristics of two materials derived from 5-sulphoisophtalic acid, 4,4-bipyridine and cobalt metal using sonochemical method. Cobalt-bipyridine complex with 5-SIP in lattice structure (RG-41) showed predominant capacitive behavior whereas Co-SIP-Bpy MOF (RG-42) exhibited significant pseudocapacitive attributes due to the presence of coordination linkage responsible for the electron transfer. Due to the effective electrochemical properties of RG-42, we implemented it practically by fabricating a hybrid device with outstanding electrochemical features, demonstrating impressive 92 % cyclic stability with energy density and power density of 51.41 Wh/kg and 800 W/kg at 1 A/g, respectively. Dunn's method was employed to obtain capacitive-diffusive contributions for both half-electrochemical cells as well as hybrid device. These results underscored the potential of RG-42 as a competitive electrode material for future energy storage applications.
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    Tuning the electrochemical performance of a copper-based 2D rectangular layered metal organic framework by incorporating reduced graphene oxide and polyaniline
    (Royal Soc Chemistry, 2026) Riasat, Madiha; Shahbaz, Muhammad; Ullah, Ghulam; Mushtaq, Muhammad Waheed; Saeed, Maham; Shahzad, Sundas; Shahzad, Ayesha
    To meet the challenge of developing efficient energy storage devices, metal organic frameworks (MOFs) with intrinsic properties have emerged as promising candidates. The conductivity and stability of the extended 1D pi-d and pi-pi stacking in a 2D MOF can be further enhanced by fabricating its composite with conductive materials. Herein, a nitrogen-containing 2D Cu-PDA MOF was synthesized and mixed with conductive materials, such as reduced graphene oxide (rGO) and polyaniline (PANI), to enhance the electrical conductivity. After structural investigation, the electrochemical attributes of Cu-PDA and its composites (Cu-PDA@rGO and Cu-PDA@PANI) have been explored by utilizing different electroanalytical techniques like CV, GCD and EIS analyses. In a three-electrode assembly, Cu-PDA@rGO shows a specific capacity of 551.31 C g-1. Hence, for practical applications, a hybrid supercapacitor has been designed by fabricating Cu-PDA@rGO against activated carbon (AC), which reveals a specific capacity of 159.4 C g-1, a specific energy of 32.10 Wh kg-1 and a specific power of 180.17 W kg-1 while maintaining a coulombic efficiency of 99.4% even after 5000 GCD cycles. These excellent findings demonstrate that Cu-PDA@rGO is a potential candidate for future energy storage devices.