Mahmoud Madian | National Research Center of Egypt (original) (raw)

Books by Mahmoud Madian

Hydrogen is an ideal energy carrier with dual benefits, being clean for environment and being ren... more Hydrogen is an ideal energy carrier with dual benefits, being clean for environment and being renewable. The Hydrogen Energy is the key issues and actions that are crucial to achieve a changeover to hydrogen energy applications as it relates to stationary and on-board applications.Hydrogen storage is most challenge to make the application into economic level. This book introduces new hydrogen storage family, which can help to solve hydrogen storage problem. Layered materials of the structure, MPS3, where M stands for transition metals and other metals, e.g. Mg, are investigated to store hydrogen. In this book the present work reports the results of a study in synthesis and characterization of a new material to be used in hydrogen storage.

Papers by Mahmoud Madian

Batteries, Oct 19, 2020

TiO 2 represents one of the promising anode materials for lithium ion batteries due to its high t... more TiO 2 represents one of the promising anode materials for lithium ion batteries due to its high thermal and chemical stability, relatively high theoretical specific capacity and low cost. However, the electrochemical performance, particularly for mesoporous TiO 2 , is limited and must be further developed. Elemental doping is a viable route to enhance rate capability and discharge capacity of TiO 2 anodes in Li-ion batteries. Usually, elemental doping requires elevated temperatures, which represents a challenge, particularly for sulfur as a dopant. In this work, S-doped TiO 2 nanotubes were successfully synthesized in situ during the electrochemical anodization of a titanium substrate at room temperature. The electrochemical anodization bath represented an ethylene glycol-based solution containing NH 4 F along with Na 2 S 2 O 5 as the sulfur source. The S-doped TiO 2 anodes demonstrated a higher areal discharge capacity of 95 µAh•cm −2 at a current rate of 100 µA•cm −2 after 100 cycles, as compared to the pure TiO 2 nanotubes (60 µAh•cm −2). S-TiO 2 also exhibited a significantly improved rate capability up to 2500 µA•cm −2 as compared to undoped TiO 2. The improved electrochemical performance, as compared to pure TiO 2 nanotubes, is attributed to a lower impedance in S-doped TiO 2 nanotubes (STNTs). Thus, the direct S-doping during the anodization process is a promising and cost-effective route towards improved TiO 2 anodes for Li-ion batteries.

Journal of materials chemistry. A, Materials for energy and sustainability, 2016

Journal of Materials Chemistry, 2016

Developing novel electrode materials is a substantial issue to improve the performance of lithium... more Developing novel electrode materials is a substantial issue to improve the performance of lithium ion batteries. In the present study, single phase Ti–Sn alloys with different Sn contents of 1 to 10 at% were used to fabricate Ti–Sn–O nanotubes via a straight-forward anodic oxidation step in an ethylene glycol-based solution containing NH₄F. Various characterization tools such as SEM, EDXS, TEM, XPS and Raman spectroscopy were used to characterize the grown nanotube films. Our results reveal the successful formation of mixed TiO₂/SnO₂ nanotubes in the applied voltage range of 10–40 V. The as-formed nanotubes are amorphous and their dimensions are precisely controlled by tuning the formation voltage which turns Ti–Sn–O nanotubes into highly attractive materials for various applications. As an example, the Ti–Sn–O nanotubes offer promising properties as anode materials in lithium ion batteries. The electrochemical performance of the grown nanotubes was evaluated against a Li/Li⁺ electr...

Batteries, 2020

TiO2 represents one of the promising anode materials for lithium ion batteries due to its high th... more TiO2 represents one of the promising anode materials for lithium ion batteries due to its high thermal and chemical stability, relatively high theoretical specific capacity and low cost. However, the electrochemical performance, particularly for mesoporous TiO2, is limited and must be further developed. Elemental doping is a viable route to enhance rate capability and discharge capacity of TiO2 anodes in Li-ion batteries. Usually, elemental doping requires elevated temperatures, which represents a challenge, particularly for sulfur as a dopant. In this work, S-doped TiO2 nanotubes were successfully synthesized in situ during the electrochemical anodization of a titanium substrate at room temperature. The electrochemical anodization bath represented an ethylene glycol-based solution containing NH4F along with Na2S2O5 as the sulfur source. The S-doped TiO2 anodes demonstrated a higher areal discharge capacity of 95 µAh·cm−2 at a current rate of 100 µA·cm−2 after 100 cycles, as compare...

Applied Materials Today, 2020

Manufacturing of binder-free mixed oxide electrodes with an unique 1D tubular morphology, high li... more Manufacturing of binder-free mixed oxide electrodes with an unique 1D tubular morphology, high lithium storage ability and long durability represents a real challenge to assemble efficient lithium ion batteries for safe operation. Herein, the successful fabrication of mixed Ti-Fe-O nanotubes (NTs) by a single potentiostatic anodization step of a TiFe 12 alloy at room temperature is reported. With the help of suitable characterization tools, the mixed oxide tubes in the different preparation stages were investigated for crystallinity and phase formation including an analysis on the structure defects which influence the material ś performance. Their morphology and element distribution were evaluated in the bulk and on the surface as well as oxidation state changes of the transition metal elements and the solid-electrolyte interphase formation were investigated up to the operando mode. The high anodization voltage along with the substrate composition induced the formation of a thin membrane layer covering the top of Ti-Fe-O NTs. The electrochemical performance of NTs as potential anodes in Li-ion batteries was evaluated vs. Li/Li + without any binder or conductive additives. The effect of the annealing temperature on crystallinity and Li-ion storage ability of NTs was investigated as well. The Ti-Fe-O NTs electrodes demonstrated an initial discharge capacity of 291 mAh g −1 at a current rate of 0.15C (1C = 335 mA g −1). The annealed crystalline NTs showed a higher reversible capacity of 155 mAh g −1 than the amorphous nanotubes after direct fabrication at room temperature (98 mAh g −1) after 50 charging/discharging cycles with a Coulombic efficiency close to 100% without a provable decomposition of the tubular structure but slight visible changes in their morphology. The noticed increase of the capacity of the Ti-Fe-O NT arrays treated at 600 °C is attributed to the enhanced ionic conductivity originated from short pathways for the Li + ion transport across the grain boundaries of the crystalline domains. In contrast, the presence of point defects, atomic displacements and planes sliding in the amorphous matrixes surrounding the crystalline entities hinder Li + ion transport through scattered diffusion pathways, and hence a lower lithium storage is demonstrated.

ECS Meeting Abstracts, 2019

TiO2-based material is widely studied as a promising anode for rechargeable lithium ion batteries... more TiO2-based material is widely studied as a promising anode for rechargeable lithium ion batteries due to its unique properties such as high safety, easy handling and low production cost. On top of that, the high structural stability of TiO2 arises from the low volume expansion of less than 4% upon cycling, without Li dendrite formation or electrolyte decomposition that turns them into stable and safe anode materials. Nevertheless, the low ionic conductivity represents the main obstacle behind the low practical capacity of TiO2 electrode. Manufacturing of TiO2 nanostructures is one of the effective solutions to create short diffusion pathways for Li, to enhance the ionic conductivity by lattice defects and, finally, the electrochemical performance of titania. TiO2 nanotubes represent the ideal one-dimensional nanostructure, especially when they are aligned and perfectly arranged in close packed arrays with high surface area. Ordered TiO2 nanotubes are commonly synthesized by the anod...

ACS Sustainable Chemistry & Engineering, 2015

ABSTRACT Electrode material characteristics need to be improved urgently to fulfill the requireme... more ABSTRACT Electrode material characteristics need to be improved urgently to fulfill the requirements for high performance lithium ion batteries. Herein, we report the use of the two-phase alloy Ti80Co20 for the growth of Ti-Co-O nanotubes (NT) employing an anodic oxidation process in a formamide-based electrolyte containing NH4F. The surface morphology and the current density for the initial nanotube formation are found to be dependent on the crystal structure of the alloy phases. XPS analyses of the grown nanotube arrays along with the oxidation state of the involved elements confirmed the formation of TiO2/CoO nanotubes under the selected process conditions. The electrochemical performance of the grown nanotubes was evaluated against a Li/Li+ electrode at different current densities of 10 – 400 µA cm-2. The results revealed that TiO2/CoO nanotubes prepared at 60 V exhibited the highest areal capacity of ~ 600 µAh cm-2 (i.e. 315 mAh g-1) at a current density of 10 µA cm-2. At higher current densities TiO2/CoO nanotubes showed nearly doubled lithium ion intercalation and a coulombic efficiency of 96 % after 100 cycles compared to lower effective TiO2 nanotubes prepared under identical conditions. The observed enhancement in the electrochemical performances could be attributed to increasing Li ion diffusion resulting from the presence of CoO nanotubes and the high surface area of the grown oxide tubes. The TiO2/CoO electrodes preserved their tubular structure after electrochemical cycling with only little changes in morphology.

Materials, 2017

TiO 2 nanotubes (NTs) synthesized by electrochemical anodization are discussed as very promising ... more TiO 2 nanotubes (NTs) synthesized by electrochemical anodization are discussed as very promising anodes for lithium ion batteries, owing to their high structural stability, high surface area, safety, and low production cost. However, their poor electronic conductivity and low Li + ion diffusivity are the main drawbacks that prevent them from achieving high electrochemical performance. Herein, we report the fabrication of a novel ternary carbon nanotubes (CNTs)@TiO 2 /CoO nanotubes composite by a two-step synthesis method. The preparation includes an initial anodic fabrication of well-ordered TiO 2 /CoO NTs from a Ti-Co alloy, followed by growing of CNTs horizontally on the top of the oxide films using a simple spray pyrolysis technique. The unique 1D structure of such a hybrid nanostructure with the inclusion of CNTs demonstrates significantly enhanced areal capacity and rate performances compared to pure TiO 2 and TiO 2 /CoO NTs, without CNTs tested under identical conditions. The findings reveal that CNTs provide a highly conductive network that improves Li + ion diffusivity, promoting a strongly favored lithium insertion into the TiO 2 /CoO NT framework, and hence resulting in high capacity and an extremely reproducible high rate capability.

Journal of Materials Chemistry A, 2016

Journal of Industrial and Engineering Chemistry, 2015

Applications Hydrogen is an ideal energy carrier with dual benefits, being clean for environment ... more Applications Hydrogen is an ideal energy carrier with dual benefits, being clean for environment and being renewable. The Hydrogen Energy is the key issues and actions that are crucial to achieve a changeover to hydrogen energy applications as it relates to stationary and on-board applications.Hydrogen storage is most challenge to make the application into economic level. This book introduces new hydrogen storage family, which can help to solve hydrogen storage problem. Layered materials of the structure, MPS3, where M stands for transition metals and other metals, e.g. Mg, are investigated to store hydrogen. In this book the present work reports the results of a study in synthesis and characterization of a new material to be used in hydrogen storage.

Journal of Solid State Chemistry, 2010

Single phase MnPS3 powder was prepared by solid state reaction between Mn. S and P carried out at... more Single phase MnPS3 powder was prepared by solid state reaction between Mn. S and P carried out at 650 ˚C in evacuated silica tube. The structure, morphology and sorption characteristics of the prepared solid were investigated. The results revealed that the obtained MnPS3 compound was capable of adsorbing 3.5 wt% hydrogen at-193 ˚C and a pressure of 30 bar. Little amount of hydrogen (0.07 wt %) was adsorbed at room temperature. The hydrogen adsorption/desorption cyclesat various temperatures did not result in irreversible chemical structural changes of the MnPS3 compound, but the microstructure after hydrogen cycling diminished and became finer.

Journal of Alloys and Compounds, 2014

Prepared CoPS and NiPS 3 are studied as new materials for hydrogen energy storage. Single phase o... more Prepared CoPS and NiPS 3 are studied as new materials for hydrogen energy storage. Single phase of CoPS and NiPS 3 were grown separately in evacuated silicatube via solid state reaction at 650°C with controlled heating rate 1°C/min. X-ray diffraction patterns confirm the formation of the desired compounds. Both CoPS and NiPS 3 exhibited high thermal stability up to 700°C and 630°C, respectively. The morphology of the prepared samples was investigated using scanning electron microscopy and folded sheets appeared in the transmission electron microscopy. The samples were exposed to 20 bar applied hydrogen pressure at 80 K. Both compounds appear to have feasible hydrogen storage capacity. CoPS was capable to adsorb 1.7 wt% while NiPS 3 storage capacity reached 1.2 wt%.

International Journal of Hydrogen Energy, 2010

Iron phosphorus trisulfide FePS 3 is related to the chalcogenides. It is characterized by layered... more Iron phosphorus trisulfide FePS 3 is related to the chalcogenides. It is characterized by layered structure. FePS 3 powder was prepared by solid state reaction and heated up to 650 C using two different heating rates 1 C/min and 40 C/min. The results showed that the FePS 3 produced with slow heating rate was highly ordered single crystalline phase while the powder produced with the fast heating rate was poly crystalline phase. The surface morphology and the grain size were influenced by the heating rate used for preparation. The thermal resistance of the highly ordered crystalline phase extended till 680 C while the less ordered one extended to 660 C. The products at 900 C revealed partial decomposition of FePS 3 with subsequent formation of iron sulfide phases poorer with sulfur element. The FePS 3 of single crystalline phase exhibited higher hydrogen sorption capacity at different temperatures than the less ordered crystalline phase. Hydrogen capacity was reduced by cycling as the interlayer gap shrinks.

Batteries, 2018

The lithium ion battery (LIB) has proven to be a very reliably used system to store electrical en... more The lithium ion battery (LIB) has proven to be a very reliably used system to store electrical energy, for either mobile or stationary applications. Among others, TiO 2-based anodes are the most attractive candidates for building safe and durable lithium ion batteries with high energy density. A variety of TiO 2 nanostructures has been thoroughly investigated as anodes in LIBs, e.g., nanoparticles, nanorods, nanoneedles, nanowires, and nanotubes discussed either in their pure form or in composites. In this review, we present the recent developments and breakthroughs demonstrated to synthesize safe, high power, and low cost nanostructured titania-based anodes. The reader is provided with an in-depth review of well-oriented TiO 2-based nanotubes fabricated by anodic oxidation. Other strategies for modification of TiO 2-based anodes with other elements or materials are also highlighted in this report.

Single crystal sheet of layered material, FePS 3 , grows inside sealed and evacuated silica tube.... more Single crystal sheet of layered material, FePS 3 , grows inside sealed and evacuated silica tube. The FePS 3 forms at 650°C under a controlled heating rate. X-ray diffraction (XRD), Scanning electron microscope (SEM) and transmission electron microscope (TEM) have been used to study the crystal structure and morphology. The XRD pattern exhibits sharp 001 reflections of the single crystal alloy sheet. The prepared samples exhibit high thermal stability with a decomposition temperature of 780 ˚C. The SEM images show smoothness of the single crystal sheets. Corrosion behavior was investigated by using open circuit potential, Tafel polarization and cyclic voltametry in presence of 10% hydrochloric acid. The crystal open circuit potential shifts to the nobler direction. There is a passive region in the anodic branch of the polarization curve. The presence of the passive region reflects high corrosion resistance. This behavior of high corrosion resistance can be rationalized on the basis that single crystals are free from grain boundaries.

Journal of Industrial and Engineering Chemistry, Jun 6, 2015

Graphene was prepared using modified Hummer method. The hydrogen storage capacity (HSC) and the k... more Graphene was prepared using modified Hummer method. The hydrogen storage capacity (HSC) and the kinetics of hydrogen up take of the graphene were investigated after doping with 5 and 10wt% Pd or Ni nanoparticles. Pd has a catalytic effect on hydrogen uptake at 80 K and 300 K. The mechanism of HSC was studied. Nickel displayed a negative hydrogen uptake at 300 K. The influence of the degree of oxidation of graphite on the hydrogen uptake of the graphene was studied. Both mild and intensive over oxidation have affected the quality of the graphene produced and consequently reduced its hydrogen uptake.

Electrode material characteristics need to be improved urgently to fulfill the requirements for h... more Electrode material characteristics need to be improved urgently to fulfill the requirements for high performance lithium ion batteries. Herein, we report the use of the two-phase alloy Ti80Co20 for the growth of Ti-Co-O nanotubes (NT) employing an anodic oxidation process in a formamide-based electrolyte containing NH4F. The surface morphology and the current density for the initial nanotube formation are found to be dependent on the crystal structure of the alloy phases. XPS analyses of the grown nanotube arrays along with the oxidation state of the involved elements confirmed the formation of TiO2/CoO nanotubes under the selected process conditions. The electrochemical performance of the grown nanotubes was evaluated against a Li/Li+ electrode at different current densities of 10 – 400 µA cm-2. The results revealed that TiO2/CoO nanotubes prepared at 60 V exhibited the highest areal capacity of ~ 600 µAh cm-2 (i.e. 315 mAh g-1) at a current density of 10 µA cm-2. At higher current densities TiO2/CoO nanotubes showed nearly doubled lithium ion intercalation and a coulombic efficiency of 96 % after 100 cycles compared to lower effective TiO2 nanotubes prepared under identical conditions. The observed enhancement in the electrochemical performances could be attributed to increasing Li ion diffusion resulting from the presence of CoO nanotubes and the high surface area of the grown oxide tubes. The TiO2/CoO electrodes preserved their tubular structure after electrochemical cycling with only little changes in morphology.