• Energy Research

The current work presents the effect of stirring hours and drying temperature on the quality of slurry, its surface morphology, and electrochemical performances of electrodes. Physical characterization studies, such as XRD, SEM, and SEM of slurry, and electrochemical characterization studies, namely, the investigation of charge-discharge capacities, rate performances, cyclability, and AC-impedance, were carried out. The cathode slurry was prepared at four different stirring intervals of 3 h, 4 h, 5 h, and 6 h and six different drying temperatures of 80, 90, 100, 110, 120, and 130 °C. The results showed that slurry obtained at a stirring time of 5 h and at a drying temperature of 120 °C exhibited best physical and electrochemical performances. SEM images showed that slurry obtained at a stirring time of 5 h has better surface uniformity and homogeneity compared to others. The electrodes prepared from this slurry also showed improved charge-discharge capacity and rate performance and low impedance. The initial discharge capacities of the electrodes, made from slurry with stirring times of 4 h, 5 h, and 6 h, were 54, 73, and 58 mA hg−1, respectively at a current rate of C/10. The current study also provides clear-cut outline steps to prepare good quality cathode slurry. This study may provide guidelines for new researchers in the field of Li-ion battery technology to overcome these issues and get first hand good quality slurry for better results.

Una batería de litio-azufre con un bajo costo, una larga vida útil, seguridad y alta densidad de energía gravimétrica puede ser una opción viable para superar las limitaciones de almacenamiento de carga de las baterías de iones de litio. Esta investigación describe cómo aumentar la vida útil y el rendimiento de las baterías de litio-azufre mediante el uso de materiales catódicos altamente conductores y livianos compuestos de poli(1,5-diaminoantraquinona) (PDAAQ) y nanopartículas de óxido de magnesio (MgO) no estequiométricas. La celda con el cátodo MgO/PDAAQ/S tiene una capacidad de descarga de 1239 mA h g–1 después de 200 ciclos. La capacidad de descarga se mantiene a 1020 mA h g–1 después de 500 ciclos. Al considerar el MgO no estequiométrico, que es rico en oxígeno, la energía de adsorción de Li se vuelve altamente negativa (-4,648 eV/átomo de Li), lo que hace que la estructura sea activa para la adsorción de cadenas de polisulfuro de litio. La novedosa combinación de un cátodo de MgO/PDAAQ/S tiene un potencial significativo para la fabricación de baterías de Li–S de alta densidad de energía gravimétrica (570 W h kg–1 por celda) durante 200 ciclos. Une batterie lithium-soufre avec un faible coût, une longue durée de vie, la sécurité et une densité d'énergie gravimétrique élevée peut être une option viable pour surmonter les limitations de stockage de charge des batteries lithium-ion. Cette recherche décrit comment augmenter la durée de vie et les performances des batteries lithium-soufre en utilisant des matériaux de cathode hautement conducteurs et légers composés de poly(1,5-diaminoanthraquinone) (PDAAQ) et de nanoparticules d'oxyde de magnésium non stoechiométriques (MgO). La cellule avec la cathode MgO/PDAAQ/S a une capacité de décharge de 1239 mA h g–1 après 200 cycles. La capacité de décharge est maintenue à 1020 mA h g–1 après 500 cycles. Lorsque l'on considère le MgO non stœchiométrique, qui est riche en oxygène, l'énergie d'adsorption du Li devient très négative (−4,648 eV/atome de Li), ce qui rend la structure active pour l'adsorption des chaînes de polysulfure de lithium. La nouvelle combinaison d'une cathode MgO/PDAAQ/S présente un potentiel important pour la fabrication de batteries Li–S à haute densité d'énergie gravimétrique (570 W h kg–1 par cellule) sur 200 cycles. A lithium-sulfur battery with a low cost, a long cycle life, safety, and high gravimetric energy density may be a viable option for overcoming the charge-storage limitations of lithium-ion batteries. This research describes how to increase the cycle life and performance of lithium-sulfur batteries by using highly conductive and lightweight cathode materials composed of poly(1,5-diaminoanthraquinone) (PDAAQ) and non-stoichiometric magnesium oxide nanoparticles (MgO). The cell with the MgO/PDAAQ/S cathode has a discharge capacity of 1239 mA h g–1 after 200 cycles. The discharge capacity is maintained at 1020 mA h g–1 after 500 cycles. When considering non-stoichiometric MgO, which is oxygen-rich, the adsorption energy of Li becomes highly negative (−4.648 eV/Li atom), making the structure active for adsorption of lithium polysulfide chains. The novel combination of a MgO/PDAAQ/S cathode has a significant potential for the fabrication of high gravimetric energy density Li–S batteries (570 W h kg–1 per cell) over 200 cycles. قد تكون بطارية الليثيوم والكبريت ذات التكلفة المنخفضة والعمر الطويل والسلامة وكثافة الطاقة العالية لقياس الجاذبية خيارًا قابلاً للتطبيق للتغلب على قيود تخزين الشحن لبطاريات الليثيوم أيون. يصف هذا البحث كيفية زيادة عمر دورة وأداء بطاريات الليثيوم والكبريت باستخدام مواد كاثود عالية التوصيل وخفيفة الوزن تتكون من جسيمات نانوية من بولي(1،5 -ديامينوأنثراكينون) (PDAAQ) وجسيمات نانوية من أكسيد المغنيسيوم غير المتكافئة (MGO). تتمتع الخلية التي تحتوي على كاثود MgO/PDAAQ/S بسعة تفريغ تبلغ 1239 مللي أمبير في الساعة جم -1 بعد 200 دورة. يتم الحفاظ على قدرة التفريغ عند 1020 مللي أمبير في الساعة ز-1 بعد 500 دورة. عند التفكير في MgO غير المتكافئ، وهو غني بالأكسجين، تصبح طاقة الامتزاز لـ Li سلبية للغاية (-4.648 إلكترون فولت/ذرة ليثيوم)، مما يجعل الهيكل نشطًا لامتزاز سلاسل كبريتيد الليثيوم. تتمتع التركيبة الجديدة من كاثود MgO/PDAAQ/S بإمكانية كبيرة لتصنيع بطاريات Li - S عالية الكثافة للطاقة الجاذبية (570 واط في الساعة كجم -1 لكل خلية) على مدار 200 دورة.

The development of efficient, low‐cost, non‐noble metal‐oxide‐based nanohybrid materials for overall water splitting is a critical strategy for enhancing clean energy use and addressing environmental issues. In this study, an interfacial engineering strategy for the development of bimetallic Co–Ni nanoparticles on graphitic carbon nitride (g‐C3N4) using ultrasonication followed by coprecipitation is conveyed. These nanoparticles demonstrate high efficacy as bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline conditions. Co–Ni nanoparticles on graphitic carbon nitride demonstrate an increased surface area via ultrasonication and subsequent coprecipitation. The g‐C3N4 combined with Co–Ni nanoparticles leads to the development of bifunctional catalysts that exhibit significant efficiency in both HER and OER, and their interfacial properties are investigated for the first time. The chemical composition and morphology of g‐C3N4 integrated with Co–Ni nanoparticles significantly influence the modulation of redox‐active sites and the facilitation of electron transfer, resulting in improved splitting efficiency. The interactions between the Co–Ni bimetal and g‐C3N4 demonstrate exceptional electrochemical performance for water splitting. Consequently, the 20% 20–Co–Ni–graphitic carbon nitride electrode demonstrated superior HER performance, comparable to the other electrodes. In the results, it is indicated that an increased molar ratio of Co and Ni incorporated in graphitic carbon nitride significantly improves HER performance.

Abstract Fluorinated α-Fe 2 O 3 nanostructures are synthesized via a facile hydrothermal route using Selectfluor™ (F-TEDA) as a fluorinating as well as growth directing agent. The addition of incrementally increasing amount of F-TEDA to Fe precursor under hydrothermal conditions resulted in preferential growth of α-Fe 2 O 3 along (110) orientation with respect to (104) direction by ~ 35%, the former being important for enhanced charge transport. On increasing fluorination, the heirarchical dendritic-type α-Fe 2 O 3 changes to a snow-flake type structure (F-TEDA-20%) anisotropically growing along the six directions however, at higher F-TEDA concentrations (≥ 30%), loosely held particulate aggregates are seen to be formed. The X-Ray Photoelectron Spectroscopy (XPS) suggest the maximum fluorinarion of α-Fe 2 O 3 at 1.21 at% in 30% F-TEDA. Further, optical absorption studies reveal reduction in optical band gap from 2.10 eV in case of pristine to 1.95 eV for fluorinated α-Fe 2 O 3 . A photoanode made by taking 20% fluorinated α-Fe 2 O 3 in a ratio of 10:90 with respect to TiO 2 (P-25) showed improved performance in dye sensitized solar cells with an increase in efficiency by ~16% in comparision to that of pristine Fe 2 O 3 and TiO 2 . Furthermore, anode consisting of thin films of fluorinated α-Fe 2 O 3 on FTO also exhibit enhanced current density on illumination of ~100 W/m 2 . The increase in photoelectrochemical activity seems to be due to the combination of two factors namely preferential growth of α-Fe 2 O 3 along (110) direction resulting in an improved charge transfer efficiency and reduced recombination losses due to the presence of fluorine.

A unique, high surface area Co3O4/SiO2–Al2O3 catalytic system has been developed for the selective deoxygenation of biomass to high quality diesel-grade hydrocarbons.

Fatty acid-based biomass is one of the most abundant organic carbon sources and has acquired significant attention as a renewable feedstock for producing renewable bio-jet fuel via hydrocatalytic processes.

AbstractAgile nanostructure architectures and smart combinations of semiconducting metal oxide materials are key features of high‐performing dye‐sensitized solar cells (DSSCs). Herein, we synthesize mesoporous solid nanospheres of ZnO–TiO2 with type‐II heterojunction and use these as an efficient photoanode material for excellent photoconversion. These polydisperse aggregates doped with 1 %, 5 %, and 10 % of ZnO exhibit improved solar cell performance with respect to pristine TiO2 under AM 1.5 G. The 1 % ZnO doped TiO2 nanosphere possess high specific surface area (84.23 m2 g−1) as a photoanode and shows high photoconversion efficiency of about 8.07 % with ca. 18 % improvement in the photocurrent density (Jsc) compare to TiO2 nanosphere. The improved solar cell performance (Δη=40 %) of ZnO decorated TiO2 nanospheres is ascribed to type‐II heterojunction of ZnO–TiO2, that reduces the electron recombination and synergistically enhances the electron mobility and charge collection capability.