scispace - formally typeset
Search or ask a question
Author

Ramazan Kahraman

Bio: Ramazan Kahraman is an academic researcher from Qatar University. The author has contributed to research in topics: Corrosion & Coating. The author has an hindex of 26, co-authored 130 publications receiving 2638 citations. Previous affiliations of Ramazan Kahraman include Montana State University & King Fahd University of Petroleum and Minerals.


Papers
More filters
Journal ArticleDOI
TL;DR: In this article, the crystal structure, electrochemical properties, and thermal stability of Na2FeP2O7, the first example ever reported in the pyrophosphate family for SIBs, are investigated.
Abstract: Considering the promising electrochemical performance of the recently reported pyrophosphate family in lithium ion batteries as well as the increasing importance of sodium ion batteries (SIBs) for emerging large-scale applications, here, the crystal structure, electrochemical properties, and thermal stability of Na2FeP2O7, the first example ever reported in the pyrophosphate family for SIBs, are investigated. Na2FeP2O7 maintains well-defined channel structures (triclinic framework under the P1 space group) and exhibits a reversible capacity of ≈90 mAh g−1 with good cycling performance. Both quasi-equilibrium measurements and first-principles calculations consistently indicate that Na2FeP2O7 undergoes two kinds of reactions over the entire voltage range of 2.0–4.5 V (vs Na/Na+): a single-phase reaction around 2.5 V and a series of two-phase reactions in the voltage range of 3.0–3.25 V. Na2FeP2O7 shows excellent thermal stability up to 500 °C, even in the partially desodiated state (NaFeP2O7), which suggests its safe character, a property that is very critical for large-scale battery applications.

295 citations

Journal ArticleDOI
TL;DR: A hierarchical porous carbon structure in which meso- and macropores are surrounded by outer micropores is introduced, serving as a "barricade" against outward dissolution of long-chain lithium polysulfides.
Abstract: Utilizing the unparalleled theoretical capacity of sulfur reaching 1675 mAh/g, lithium-sulfur (Li-S) batteries have been counted as promising enablers of future lithium ion battery (LIB) applications requiring high energy densities. Nevertheless, most sulfur electrodes suffer from insufficient cycle lives originating from dissolution of lithium polysulfides. As a fundamental solution to this chronic shortcoming, herein, we introduce a hierarchical porous carbon structure in which meso- and macropores are surrounded by outer micropores. Sulfur was infiltrated mainly into the inner meso- and macropores, while the outer micropores remained empty, thus serving as a "barricade" against outward dissolution of long-chain lithium polysulfides. On the basis of this systematic design, the sulfur electrode delivered 1412 mAh/g sulfur with excellent capacity retention of 77% after 500 cycles. Also, a control study suggests that even when sulfur is loaded into the outer micropores, the robust cycling performance is preserved by engaging small sulfur crystal structures (S2-4). Furthermore, the hierarchical porous carbon was produced in ultrahigh speed by scalable spray pyrolysis. Each porous carbon particle was synthesized through 5 s of carrier gas flow in a reaction tube.

231 citations

Journal ArticleDOI
TL;DR: In this article, the influence of adhesive thickness and aluminum filler content on the mechanical performance of aluminum joints bonded by aluminum powder filled epoxy was determined by utilizing the single-lap shear test.

192 citations

Journal ArticleDOI
TL;DR: Using first-principles calculations, it is found that the significantly enhanced kinetics of Na( 2)MnP(2)O(7) is mainly due to the locally flexible accommodation of Jahn-Teller distortions aided by the corner-sharing crystal structure in triclinic Na(2).
Abstract: Sodium ion batteries (SIBs) have many advantages such as the low price and abundance of sodium raw materials that are suitable for large-scale energy storage applications. Herein, we report an Mn-based pyrophosphate, Na(2)MnP(2)O(7), as a new SIB cathode material. Unlike most Mn-based cathode materials, which suffer severely from sluggish kinetics, Na(2)MnP(2)O(7) exhibits good electrochemical activity at ~3.8 V vs Na/Na(+) with a reversible capacity of 90 mAh g(-1) at room temperature. It also shows an excellent cycling and rate performance: 96% capacity retention after 30 cycles and 70% capacity retention at a c-rate increase from 0.05C to 1C. These electrochemical activities of the Mn-containing cathode material even at room temperature with relatively large particle sizes are remarkable considering an almost complete inactivity of the Li counterpart, Li(2)MnP(2)O(7). Using first-principles calculations, we find that the significantly enhanced kinetics of Na(2)MnP(2)O(7) is mainly due to the locally flexible accommodation of Jahn-Teller distortions aided by the corner-sharing crystal structure in triclinic Na(2)MnP(2)O(7). By contrast, in monoclinic Li(2)MnP(2)O(7), the edge-sharing geometry causes multiple bonds to be broken and formed during charging reaction with a large degree of atomic rearrangements. We expect that the similar computational strategy to analyze the atomic rearrangements can be used to predict the kinetics behavior when exploring new cathode candidates.

158 citations

Journal ArticleDOI
TL;DR: In this paper, a hybrid composites of date palm wood flour/glass fibre were prepared by different weight ratios of the two reinforcements and the results showed that glass fiber reinforced composites showed higher hardness than other composites.

147 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: Current research on materials is summarized and discussed and future directions for SIBs are proposed to provide important insights into scientific and practical issues in the development of S IBs.
Abstract: Energy production and storage technologies have attracted a great deal of attention for day-to-day applications. In recent decades, advances in lithium-ion battery (LIB) technology have improved living conditions around the globe. LIBs are used in most mobile electronic devices as well as in zero-emission electronic vehicles. However, there are increasing concerns regarding load leveling of renewable energy sources and the smart grid as well as the sustainability of lithium sources due to their limited availability and consequent expected price increase. Therefore, whether LIBs alone can satisfy the rising demand for small- and/or mid-to-large-format energy storage applications remains unclear. To mitigate these issues, recent research has focused on alternative energy storage systems. Sodium-ion batteries (SIBs) are considered as the best candidate power sources because sodium is widely available and exhibits similar chemistry to that of LIBs; therefore, SIBs are promising next-generation alternatives. Recently, sodiated layer transition metal oxides, phosphates and organic compounds have been introduced as cathode materials for SIBs. Simultaneously, recent developments have been facilitated by the use of select carbonaceous materials, transition metal oxides (or sulfides), and intermetallic and organic compounds as anodes for SIBs. Apart from electrode materials, suitable electrolytes, additives, and binders are equally important for the development of practical SIBs. Despite developments in electrode materials and other components, there remain several challenges, including cell design and electrode balancing, in the application of sodium ion cells. In this article, we summarize and discuss current research on materials and propose future directions for SIBs. This will provide important insights into scientific and practical issues in the development of SIBs.

3,009 citations

Journal ArticleDOI
TL;DR: In this paper, a variety of electrode materials including cathodes and anodes as well as electrolytes for room-temperature stationary sodium-ion batteries are briefly reviewed and compared the difference in storage behavior between Na and Li in their analogous electrodes and summarize the sodium storage mechanisms in available electrode materials.
Abstract: Room-temperature stationary sodium-ion batteries have attracted great attention particularly in large-scale electric energy storage applications for renewable energy and smart grid because of the huge abundant sodium resources and low cost. In this article, a variety of electrode materials including cathodes and anodes as well as electrolytes for room-temperature stationary sodium-ion batteries are briefly reviewed. We compare the difference in storage behavior between Na and Li in their analogous electrodes and summarize the sodium storage mechanisms in the available electrode materials. This review also includes some new results from our group and our thoughts on developing new materials. Some perspectives and directions on designing better materials for practical applications are pointed out based on knowledge from the literature and our experience. Through this extensive literature review, the search for suitable electrode and electrolyte materials for stationary sodium-ion batteries is still challenging. However, after intensive research efforts, we believe that low-cost, long-life and room-temperature sodium-ion batteries would be promising for applications in large-scale energy storage system in the near future.

2,687 citations

Journal ArticleDOI
TL;DR: This review aims to summarize major developments in the field of lithium-sulfur batteries, starting from an overview of their electrochemistry, technical challenges and potential solutions, along with some theoretical calculation results to advance the understanding of the material interactions involved.
Abstract: Due to their high energy density and low material cost, lithium–sulfur batteries represent a promising energy storage system for a multitude of emerging applications, ranging from stationary grid storage to mobile electric vehicles. This review aims to summarize major developments in the field of lithium–sulfur batteries, starting from an overview of their electrochemistry, technical challenges and potential solutions, along with some theoretical calculation results to advance our understanding of the material interactions involved. Next, we examine the most extensively-used design strategy: encapsulation of sulfur cathodes in carbon host materials. Other emerging host materials, such as polymeric and inorganic materials, are discussed as well. This is followed by a survey of novel battery configurations, including the use of lithium sulfide cathodes and lithium polysulfide catholytes, as well as recent burgeoning efforts in the modification of separators and protection of lithium metal anodes. Finally, we conclude with an outlook section to offer some insight on the future directions and prospects of lithium–sulfur batteries.

1,816 citations

Journal ArticleDOI
TL;DR: In this paper, the authors highlight the recent progress in high-sulfur-loading Li-S batteries enabled by hierarchical design principles at multiscale, particularly, basic insights into the interfacial reactions, strategies for mesoscale assembly, unique architectures, and configurational innovation in the cathode, anode, and separator.
Abstract: Owing to high specific energy, low cost, and environmental friendliness, lithium–sulfur (Li–S) batteries hold great promise to meet the increasing demand for advanced energy storage beyond portable electronics, and to mitigate environmental problems. However, the application of Li–S batteries is challenged by several obstacles, including their short life and low sulfur utilization, which become more serious when sulfur loading is increased to the practically accepted level above 3–5 mg cm−2. More and more efforts have been made recently to overcome the barriers toward commercially viable Li–S batteries with a high sulfur loading. This review highlights the recent progress in high-sulfur-loading Li–S batteries enabled by hierarchical design principles at multiscale. Particularly, basic insights into the interfacial reactions, strategies for mesoscale assembly, unique architectures, and configurational innovation in the cathode, anode, and separator are under specific concerns. Hierarchy in the multiscale design is proposed to guide the future development of high-sulfur-loading Li–S batteries.

1,364 citations