Surface-Engineered TiO2 for High-Performance Flexible Supercapacitor Applications

Research Abstract

Titanium dioxide (TiO2) shows excellent pseudocapacitive properties. However, the low internal conductivity of TiO2 limits its use in supercapacitor applications. Therefore, an efficient surface engineering process was developed to enhance the overall pseudocapacitive performance of rutile TiO2 nanorods. Specifically, surface-engineered TiO2 nanorod arrays coordinated on carbon cloth were established through the Kapton tape-assisted hydrothermal route. X-ray diffraction analysis confirmed the formation of a tetragonal TiO2 rutile phase. Morphological analysis revealed the formation of uniform nanorods with an apparent high surface-to-volume aspect ratio. X-ray photoelectron spectroscopy analysis showed that the TiO2 synthesized in the presence of Kapton tape and annealed under air had high content of hydroxyl groups and Ti3+, which is favorable for supercapacitor performance. Surface treatment of the samples led to significantly enhanced conductivity and electrochemical behavior of TiO2. The surface-engineered TiO2 nanorod arrays show specific capacitance of about 57.62 mF/cm2 at 10 mV/s in 2 M KOH, with excellent rate capability of about 83% at 200 mV/s, and also exhibit long cycle life, retaining 91% of their original capacitance after 10,000 charge/discharge cycles, which is among the highest values reported for TiO2-based supercapacitors.

Research Authors
Abdelnaby M Elshahawy, Saeid M Elkatlawy, Mustafa S Shalaby, Cao Guan, John Wang
Research Date
Research Department
Department of physics
Research Journal
Journal of Electronic Materials
Research Member
Abdelnaby Mohamed Kotb Elshahawy
Research Pages
1347-1356
Research Publisher
Springer US
Research Rank
International Q2
Research Vol
52
Research Website
https://doi.org/10.1007/s11664-022-10084-0
Research Year
2023

3D Printed Graphene-Based Metamaterials: Guesting Multi-Functionality in One Gain

Research Abstract

Advanced functional materials with fascinating properties and extended structural design have greatly broadened their applications. Metamaterials, exhibiting unprecedented physical properties (mechanical, electromagnetic, acoustic, etc.), are considered frontiers of physics, material science, and engineering. With the emerging 3D printing technology, the manufacturing of metamaterials becomes much more convenient. Graphene, due to its superior properties such as large surface area, superior electrical/thermal conductivity, and outstanding mechanical properties, shows promising applications to add multi-functionality into existing metamaterials for various applications. In this review, the aim is to outline the latest developments and applications of 3D printed graphene-based metamaterials. The structure design of different types of metamaterials and the fabrication strategies for 3D printed graphene-based materials are first reviewed. Then the representative explorations of 3D printed graphene-based metamaterials and multi-functionality that can be introduced with such a combination are further discussed. Subsequently, challenges and opportunities are provided, seeking to point out future directions of 3D printed graphene-based metamaterials.

Research Authors
Junjie Du, Gangwen Fu, Xi Xu, Abdelnaby M Elshahawy, Cao Guan
Research Date
Research Department
Department of physics
Research Journal
Small
Research Member
Abdelnaby Mohamed Kotb Elshahawy
Research Pages
2207833
Research Publisher
Wiley-VCH GmbH
Research Rank
International Q1
Research Vol
19
Research Website
https://doi.org/10.1002/smll.202207833
Research Year
2023

Constructive Electroactive 2D/2D MoS2-N-rGO and 1D/2D Bi2S3-N-rGO Heterostructure for Excellent Mo-Bi Supercapattery Applications

Research Abstract

Metal sulfides including MoS2 and Bi2S3 materials, have been considered as a strong candidate for supercapacitor applications. However, the short-term stability and low surface area have limited the establishment of such eco-friendly materials in energy storage. In this work, an effective strategy is designed to in-situ combine transition metal sulfides with nitrogen doped reduced graphene oxide hydrogels and improve the overall supercapattery properties. Precisely, MoS2-N-rGO and Bi2S3-N-rGO hydrogels have been developed via hydrothermal route. The morphological analysis manifests two-dimensional 2D/2D heterostructure for the MoS2-N-rGO and 1D/2D heterostructure for the Bi2S3-N-rGO. The cyclic voltammetry studies showed a battery-like electrochemical behavior for the synthesized hydrogels. The calculated capacitance for MoS2-N-rGO and Bi2S3-N-rGO are about 438 F/g and 342 F/g @ 1 A/g with 50% and 41% of their capacitance initial values @ 20 A/g, respectively. The cycling performance showed that MoS2-N-rGO and Bi2S3-N-rGO can maintain 90% and 98% of their original specific capacitance after 1000 cycles life. Furthermore, the supercapattery device was fabricated using MoS2-N-rGO as cathode and Bi2S3-N-rGO as anode. The hybrid device is capable of offering 33.4 Wh/kg energy density, at 0.85 kW/kg power density, with 44.7% retention at 20 A/g. Notably, the overall electrochemical behavior of Mo-Bi supercapattery device is remarkable among the pointed behaviors for other hybrid devices.

Research Authors
Saeid M Elkatlawy, Abdelhamid A Sakr, John Wang, Abdelnaby M Elshahawy
Research Date
Research Department
Department of physics
Research Journal
Journal of Inorganic and Organometallic Polymers and Materials
Research Member
Abdelnaby Mohamed Kotb Elshahawy
Research Pages
1741-1754
Research Publisher
Springer US
Research Rank
International Q2
Research Vol
33
Research Website
https://doi.org/10.1007/s10904-023-02607-x
Research Year
2023

NANOMATERIALS IMPLANTATION FOR ACCELERATING BONE HEALING

Research Abstract

The present study was conducted on 9 non-medicated, clinically healthy, adult mongrel male dogs. The dogs had no orthopedic abnormalities. Dogs were subjected to mid-diaphyseal circular bone defect (0.8 cm in diameter) in the left radius bones under general anesthesia. Dogs were divided randomly to be allocated into two groups, each of 3 dogs. The treated group (group T, n = 3), in which bone defects were implanted with the titanium oxide/graphene oxide/chitosan nanocomposite. The control group (group C, n = 3), in which bone defects were allowed for spontaneous healing. Dogs were subjected to clinical and radiographical evaluation 30 days postoperatively. All surgical procedures were conducted under the effect of total intravenous anesthesia (TIVA). Digital cranio-palmar and lateral views were taken for the operated limbs. Cortical defects and depth of the bone defects were recorded using the RadiAnt DICOM viewer version 1.1.2022 software. There was a significant decrease (P < 0.05) in the cortical defect in the treated group compared with the control groups 30 days postoperatively. The treated group recorded a significant decrease (P < 0.05) in 30 days compared to the baseline value. The depth of the bone defects decreased significantly (P < 0.05) in the treated group compared with the untreated group 30 days post-induction of the bone defects. There was a significant decrease (P < 0.05) in the treated group on 30 days compared to the baseline value. The titanium oxide/graphene oxide/chitosan nanocomposite accelerates the healing of bone defects.

Research Authors
Ahmed Ibrahim, Abdelnaby Elshahawy, KHALED HASSANEIN, Shereen Ibrahim Zakaria Hussein, MOHAMMED SEMIEKA
Research Date
Research Department
Department of physics
Research Journal
Assiut Veterinary Medical Journal
Research Member
Abdelnaby Mohamed Kotb Elshahawy
Research Pages
1-6
Research Publisher
Assiut University, Faculty of Veterinary Medicine
Research Rank
N/A
Research Vol
69
Research Website
DOI: 10.21608/avmj.2023.196707.1127
Research Year
2023

Lithium dopant assisted surface modification Zn ferrites for high-performance supercapacitor applications

Research Abstract
Ferrite materials, such as Zn ferrites, show novel electrochemical properties. However, their low internal conductivity limits their usage in supercapacitor applications. Hence, developing an efficient strategy to improve the electrochemical properties of Zn ferrites has become a critical demand. Therefore, we introduce alkali metals, namely lithium, to induce the surface modification of Zn ferrites using the sol-gel–assisted combustion method. The X-ray diffraction (XRD) study has verified that the formation of cubic Li-doped Zn ferrites with hematite as a minor phase. The X-ray Photoelectron Spectroscopy (XPS) analysis establish that the LixZn1-xFe2O4 with x = 0.10 nanoparticles has a high hydroxyl group content with an inverse spinel structure. Li-doped Zn ferrites samples exhibit specific capacitance in decreasing order of x = 0.10 (898 F/g) > x = 0.05 (527 F/g) > x = 0.00 (42 F/g) at current density 2 A/g s in 6 M KOH. Furthermore, LixZn1-xFe2O4 with x = 0.10 displays good cycle life where it maintains around 80 % of its capacitance after 1000 charge–discharge cycles while retaining up to 66 % of its specific capacitance after 5000 cycles. It is worth noting that this electrochemical performance is among the highest values recorded for Zn ferrite–based materials for supercapacitor applications.
Research Authors
MH Mahmoud, Abdelnaby M Elshahawy, TA Taha
Research Date
Research Department
Department of physics
Research Journal
Journal of Energy Storage
Research Member
Abdelnaby Mohamed Kotb Elshahawy
Research Pages
107881
Research Publisher
Elsevier
Research Rank
International Q1
Research Vol
68
Research Website
https://doi.org/10.1016/j.est.2023.107881
Research Year
2023

Recent advances of vanadium oxides and their derivatives in supercapacitor applications: A comprehensive review

Research Abstract
Because of the complexity of various oxidation states of vanadium, vanadium oxides show a large variety of stable and metastable structures, which pose an inevitable challenge to synthesize vanadium oxides with high purity, well-controlled stoichiometry, to their different morphologies and meticulously designed nanostructures, a must for high electrochemical performance devices for Supercapacitors. Vanadium oxide-based materials have been extensively studied for their metal-insulator transition behavior, and their unique characteristics that making them a promising candidate for electrochemical performance, supercapacitors and energy storage capabilities. This review article will discuss the synthesis methods, structural characterization techniques, and applications of vanadium oxide-based materials. We will also highlight the recent advances in vanadium oxide and provide insights into these materials' prospects in the Supercapacitors field.
Research Authors
Hadeer Gamal, Abdelnaby M Elshahawy, Shymaa S Medany, Mahmoud A Hefnawy, MS Shalaby
Research Date
Research Department
Department of physics
Research Journal
Journal of Energy Storage
Research Member
Abdelnaby Mohamed Kotb Elshahawy
Research Pages
109788
Research Publisher
Elsevier
Research Rank
International Q1
Research Vol
76
Research Website
https://doi.org/10.1016/j.est.2023.109788
Research Year
2024

Materials and structural design for preferable Zn deposition behavior toward stable Zn anodes

Research Abstract

Benefiting from the high capacity of Zn metal anodes and intrinsic safety of aqueous electrolytes, rechargeable Zn ion batteries (ZIBs) show promising application in the post-lithium-ion period, exhibiting good safety, low cost, and high energy density. However, its commercialization still faces problems with low Coulombic efficiency and unsatisfied cycling performance due to the poor Zn/Zn2+ reversibility that occurred on the Zn anode. To improve the stability of the Zn anode, optimizing the Zn deposition behavior is an efficient way, which can enhance the subsequent striping efficiency and limit the dendrite growth. The Zn deposition is a controlled kinetics-diffusion joint process that is affected by various factors, such as the interaction between Zn2+ ions and Zn anodes, ion concentration gradient, and current distribution. In this review, from an electrochemical perspective, we first overview the factors affecting the Zn deposition behavior and summarize the modification principles. Subsequently, strategies proposed for interfacial modification and 3D structural design as well as the corresponding mechanisms are summarized. Finally, the existing challenges, perspectives on further development direction, and outlook for practical applications of ZIBs are proposed.

Research Authors
Qinghe Cao, Yong Gao, Jie Pu, Abdelnaby M Elshahawy, Cao Guan
Research Date
Research Department
Department of physics
Research Journal
SmartMat
Research Member
Abdelnaby Mohamed Kotb Elshahawy
Research Pages
e1194
Research Publisher
John Wiley & Sons Australia, Ltd.
Research Rank
International Q1
Research Vol
5
Research Website
https://doi.org/10.1002/smm2.1194
Research Year
2024

Evaluation of a chitosan/polyvinyl alcohol hydrogel loaded with graphene oxide and nano TiO2 for bone defect reconstruction in a dog model

Research Abstract

This study evaluated the application of chitosan/polyvinyl alcohol/graphene oxide/nano titanium oxide (CS/PVA/GO/nano TiO2) hydrogels for bone defect reconstruction in dogs. Dogs were subjected to mid-diaphyseal circular bone defects (0.8 cm2) in the radius bones. Bone defects were implanted with the hydrogel in the treated group (n = 9), while the control group were subjected to spontaneous healing (n = 9). Dogs were subjected to clinical, radiographic, and scanning electron microscopy (SEM) evaluations at 15-, 30-, and 45-days post-surgery. Dogs in the treated group recorded no lameness by the end of the third week post-surgery, while dogs in the untreated group still exhibited lameness of grade 1. There was a significant decrease (p < 0.05) in the cortical defect (mm) of the treated group (5.46 ± 0.17 and 1.45 ± 0.13) compared with the control group (7.57 ± 0.05 and 7.59 ± 0.06) at 30- and 45-days post-surgery, respectively. The depth of the bone defects (mm) decreased significantly (p < 0.05) in the treated group (2.26 ± 0.12 and 0.008 ± 0.002) compared with the untreated group (4.05 ± 0.05 and 2.16 ± 0.07) at 30- and 45-days post-surgery, respectively. Throughout the period of study, there was a significant increase (p < 0.05) in the radiographic density of the bone defects (px) in the treated group (474 ± 17.88) compared with that in the control group (619.6 ± 6.85). SEM results revealed complete closure of the bone defects in the treated group. Thus, implantation of bone defects with the CS/PVA/GO/nano TiO2 hydrogel represents a promising bone graft substitute for accelerating bone healing.

Research Authors
Ahmed Ibrahim, Khaled MA Hassanein, Shereen Ibrahim Zakaria Hussein, Mohammed MA Semieka, Abdelnaby M Elshahawy
Research Date
Research Department
Department of physics
Research Journal
Journal of Materials Chemistry B
Research Member
Abdelnaby Mohamed Kotb Elshahawy
Research Pages
3581-3592
Research Publisher
Royal Society of Chemistry
Research Rank
International Q1
Research Vol
13
Research Website
DOI: 10.1039/D4TB02553A
Research Year
2025

Hygroscopic V-MOF Layer Enabling Stable Zn-Ion Batteries Under Fast and Deep Charging/Discharging

Research Abstract

Achieving stable Zn-ion batteries operating under high charging–discharging rates and a high depth of discharge (DOD) remains challenging due to intensified dendrite growth and side reaction. This work introduces a novel hygroscopic vanadium metal–organic framework (V-MOF) as a multifunctional protective layer to achieve an outstanding Zn anode. The as-fabricated battery can remain stable and high performance with high DOD of 85.5% and fast discharging rate of 50 mAh/cm2. The hygroscopic V-MOF nature removes solvated shells and captures water as bonded/iced water within its structure, significantly suppressing side reactions. In addition, the V-MOF coating optimized the electrical field, inhibited the cracks, and reduced the Zn dendrite formation even at a high rate of 50 mAh/cm2, due to the construction of electrolyte-philic and smooth surface. Consequently, the hygroscopic Zn/V-MOF symmetrical cells achieve exceptional performance over 1000 h under 50 mA/cm2 (50 mAh/cm2) with 85.5% DOD. The Zn/V-MOF||V2O3/NC cell shows a capacity of 267 mAh/g at 0.5 A/g with excellent rate capability (100 mAh/g @20 A/g). In addition, it achieves an outstanding lifetime over 3300 cycles @ 5 A/g. The results at high rates with high DOD highlight the magnificent potential of hygroscopic V-MOF to achieve outstanding Zn anode and large-scale aqueous batteries.

Research Authors
Abdelnaby M Elshahawy, Yong Gao, Jipeng Chen, Ximeng Liu
Research Date
Research Department
Department of physics
Research Journal
Advanced Energy Materials
Research Member
Abdelnaby Mohamed Kotb Elshahawy
Research Pages
e05767
Research Publisher
Wiley-VCH GmbH
Research Rank
International Q1
Research Vol
0
Research Website
https://doi.org/10.1002/aenm.202505767
Research Year
2025

Photo-motivated heterojunctions coupling built-in electric field stimulating sulfur redox kinetics for lithium-sulfur batteries

Research Abstract
Enhancing the redox kinetics of polysulfides in lithium-sulfur batteries (Li-Ss) by photo-irradiation represents a practical approach. Herein, a photo-assisted rechargeable Li-Ss featuring BVO (BiVO4)/Co3O4 heterojunction nanosheets as a multifunctional cathode is designed. The photogenerated electron-hole pairs in BVO synergistically enhance polysulfide redox kinetics during both charging and discharging. Notably, the internal electric field created by BVO/Co3O4 interface effectively suppresses carrier recombination. Photogenerated electrons accelerate the reduction of S8 to Li2S, while holes promote the oxidation of Li2S to S8. As a result, significant specific capacity enhancement to 1550 mAh/g at 0.5 mA cm−2 is observed. Strikingly, the soft pack batteries can achieve a capacity of 300 mAh/g only by illumination. This research offers a promising avenue for enhancing polysulfide redox kinetics by harnessing and storing solar energy.
Research Authors
Haifeng Zhang, Fei Ma, Ting Meng, Junwei Li, Haifei Zhu, Zeyu Geng, Wenbo Zhao, Xiaohan Wang, Penghui Wu, Abdelnaby M Elshahawy, Qianrui Gao, Quande Che
Research Date
Research Department
Department of physics
Research Journal
Chemical Engineering Journal
Research Member
Abdelnaby Mohamed Kotb Elshahawy
Research Pages
160356
Research Publisher
Elsevier
Research Rank
International Q1
Research Vol
506
Research Website
https://doi.org/10.1016/j.cej.2025.160356
Research Year
2025
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