Browsing by Subject "Batteries"
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Item Open Access Alkali metal intercalation in MXene/Graphene heterostructures: a new platform for ion battery applications(American Chemical Society, 2019) Demiroğlu, İ.; Peeters, F. M.; Gülseren, Oğuz; Çakır, D.; Sevik, C.The adsorption and diffusion of Na, K, and Ca atoms on MXene/graphene heterostructures of MXene systems Sc2C(OH)2, Ti2CO2, and V2CO2 are systematically investigated by using first-principles methods. We found that alkali metal intercalation is energetically favorable and thermally stable for Ti2CO2/graphene and V2CO2/graphene heterostructures but not for Sc2C(OH)2. Diffusion kinetics calculations showed the advantage of MXene/graphene heterostructures over sole MXene systems as the energy barriers are halved for the considered alkali metals. Low energy barriers are found for Na and K ions, which are promising for fast charge/discharge rates. Calculated voltage profiles reveal that estimated high capacities can be fully achieved for Na ion in V2CO2/graphene and Ti2CO2/graphene heterostructures. Our results indicate that Ti2CO2/graphene and V2CO2/graphene electrode materials are very promising for Na ion battery applications. The former could be exploited for low voltage applications while the latter will be more appropriate for higher voltages.Item Embargo Continuous conducting architecture developed by supporting Prussian blue analogue on metal-organic framework derived carbon-doped manganese- oxide nanorods for high-performance sodium-ion batteries(Elsevier BV, 2023-07-03) Ullah, Irfan; Saeed, Roheen; Inayat, Abid; Zubair, Muhammad; Wu, Xianyong; Duran, Hatice; Haider, Ali; Pope, Michael A.; Hussain, IrshadPrussian blue analogues (PBA) are regarded as promising cathode materials for sodium-ion batteries (SIBs) owing to their open framework with large interstitial sites to accommodate Na+ ions. However, PBA suffer from low electronic conductivity and mechanical instability, which may be improved by their structural modification leading to enhanced kinetics. In this regard, we report an in-situ integration of ultra-small PBA cubes into three-dimensional metal organic framework (MOF) derived carbon-doped manganese oxide nanorods (C-Mn2O3), which form a continuous conductive architecture with intimate PBA/C-Mn2O3 contact. The C-Mn2O3 nanorods provide nucleation sites for the growth of PBA cubes and further act as the electronic pathway to improve electrode reaction kinetics. This hierarchical configuration effectively buffers the lattice expansion, which improve the structural stability of NiCoPBA. Consequently, the composite exhibits promising performance in aqueous Na+ batteries. Specifically, it delivers a high capacity of 97 mAh/g within a narrow potential window of and retained 82% capacity for 1000 cycles in aqueous electrolyte. It shows even higher capacity of 136 mAh/g and similar capacity retention (76% after 1000 cycles) in non-aqueous electrolytes. The promising performance of developed materials demonstrates the significant impact decreasing the size of PBA cubes has on the capacity by reducing the diffusion pathways and thus facilitating intercalation/deintercalation within the cubes. This study offers new insights of exploiting redox-active substrates to modify and stabilize PBA materials for energy storage applications.Item Open Access Electrochemical noise analysis in batteries(Elsevier, 2022-12-10) Karaoğlu, Gözde; Hatipoğlu, Gizem; Ulgut, BurakElectrochemical noise is invaluable in the investigations of stochastic electrochemical processes. Though historically it has been applied almost exclusively to crevice and pitting corrosion studies, application to batteries is interesting for basic science and shows a huge potential for non-perturbing real-time sensor development. Given this promise, noise studies on batteries are starting to appear in the literature. In this manuscript, we are going to critically evaluate the small but emerging body of literature and investigate the mathematical methods employed. We will discuss the intricacies of electrochemical noise applied to batteries both in measurements and in analysis in order to initiate a deeper discussion. In conclusion, we argue that reliance on mathematical methods alone is not the answer, as all mathematical methods use require parameters to guide the analysis. Instead, post-mortem characterizations of batteries can guide the understanding of noise signals measured in batteries, guiding potential mathematical analysis methods and their steps.Item Open Access Electrospinning combined with atomic layer deposition to generate applied nanomaterials: A review(American Chemical Society, 2020) Vempati, S.; Ranjith, K. S.; Topuz, Fuat; Bıyıklı, Necmi; Uyar, TamerCombining different material processing techniques is one of the keys to obtain materials that depict synergistic properties. In this review, we have reviewed a combination of two highly potential techniques, namely, electrospinning and atomic layer deposition (ALD), in the view of various applications. Over the past 10 years, our research groups are involved in the exploration of employing this combination for a range of applications. We also include some basic information on both the processes and diversity of nanostructures as a result of their combination. Nonwoven nanofiber membranes are excellent candidates for a wide range of applications. Also, they can act as templates to produce various other kinds of nanostructures when combined with ALD in small/large scale production. These nanostructures could be used as such or further subjected to other processing techniques yielding hierarchical structures. In this review, we exclusively survey and highlight the unique capabilities of combined electrospinning and ALD for applications in catalysis, photocatalysis, solar cells, batteries and gas sensors.Item Open Access A method for voltage noise measurement and ıts application to primary batteries(ECS, 2018) Ülgüt, Burak; Uzundal, Can BerkThough proven effective in localized corrosion studies, electrochemical noise measurements in batteries with Lithium based chemistries suffer from lack of well–defined measurement and analysis methods. The high capacitance electrodes made out of highly porous materials requires noise measurements to be extremely precise since the small charge due to stochastic events leading to electrochemical noise leads to very small voltage changes due to the large capacitance. Typically, the required precision is achieved by high gain after the offset is corrected. In this article, we are introducing a new offset correction scheme that mitigates the negative effects of electronic offset reduction methods. Using this new offset correction scheme we report the measurement of the otherwise elusive voltage noise of primary Li batteries.Item Open Access The state of the art in mobile graphics research(Institute of Electrical and Electronics Engineers, 2008) Capin, T.; Pulli, K.; Akenine-Möller, T.High-quality computer graphics let mobile-device users access more compelling content. Still, the devices' limitations and requirements differ substantially from those of a PC. This survey of mobile graphics research describes current solutions in terms of specialized hardware (including 3D displays), rendering and transmission, visualization, and user interfaces. © 2008 IEEE.Item Open Access A study on GaN-based betavoltaic batteries(Institute of Physics Publishing Ltd., 2022-10-27) Toprak, Ahmet; Yılmaz, Doğan; Özbay, EkmelIn this paper, a GaN-based betavoltaic epitaxial structure was grown by metal–organic chemical vapor deposition and a p-type ohmic contact was studied for different Ni/Au metal thickness ratios, temperature dependent in N2:O2 (1:1) gas atmosphere and different surface treatments for this epitaxial structure. Transfer length method measurements were done after each different process condition in order to check specific contact resistivities. GaN-based betavoltaic batteries were fabricated and a scanning electron microscope (SEM) was used as an electron source to test these devices. For this purpose, devices connected to a printed circuit board were exposed to an electron current of 1.5 nA with 17 keV energy in the SEM. For 1 × 1 mm2 devices, a dark current value of 2.8 pA at 0 V, fill factor of 0.35, maximum power conversion efficiency of 3.92%, and maximum output power of 1 µW were obtained.Item Open Access Tailoring insoluble nanobelts into soluble anti-UV nanopotpourris(Royal Society of Chemistry, 2011) Wang, J.; Sun, X. W.; Jiao, Z.; Khoo, E.; Lee, P. S.; Ma, J.; Demir, Hilmi VolkanSoluble, transparent and anti-UV nanopotpourris have been prepared by tailoring long nanobelts. The strains and layered structures facilitate the breaking of the as-synthesized nanobelts under an applied mechanical action. The developed tailoring process of nanobelts is a general top-down secondary processing of layered nanostructures at the nanoscale level, which can be expended to the modifications of layered nanowires, nanotubes and hierarchical nanostructures. By tailoring, the size, morphology and solubility are modified, which may open up an area of advanced processing of nanomaterials and hint at some potential applications. Because of the excellent solubility of the tailored nanopotpourris, they are easily dispersed in cosmetics or polymer films, which are quite useful for some anti-UV protection applications, such as anti-UV sunscreen creams and anti-UV window films for vehicles and buildings.