Surface Modified Metal Hydrides as Negative Electrodes in NiMH Batteries

Download

index.pdf

Date

2018-10-28

Author

Eyövge, Cavit
Şahin, Ezgi Onur
Öztürk, Tayfur

Metadata

Show full item record

Item Usage Stats

322
views

148
downloads

Surface Modified Metal Hydrides as Negative Electrodes in NiMH BatteriesCavit Eyovge1,2, Ezgi Onur Sahin1,2 and Tayfur Ozturk1,21Center for Energy Materials and Storage Devices, Middle East Technical University, Ankara 2Dept. of Metallurgical and Materials Engineering, Middle East Technical University, Ankara There is a renewed interest in NiMH batteries with improved energy densities that could approach those of Li-ion batteries. Efforts to improve the energy density concentrates on alternative anode as well as cathode materials. For anode, AB2 and Mg based alloys are candidates with potentials that go beyond the capacity achieved with rare-earth based AB5 compounds. In a recent study [1] we have shown an AB2 alloy which is sluggish in its activation could readily be activated when it was surface modified with hot-alkaline treatment. The treatment resulting in fine porous surface rich in Ni not only activates the alloy but it also increases the discharge capacity by a significant amount. This was attributed to positive effect of porous surface where hydrogen evolution was made difficult by the associated stabilizing effect. For Mg based alloys, we have investigated A2B7 alloy where the amount of Mg is quite low and an amorphous Mg50Ni50 alloy. Here rather than modifying the powders, the electrode itself was modified by nafion coating. The electrodes were tested both in bare and coated form with a notable difference in discharge capacity. Nafion coating increased maximum attainable discharge capacity in both alloys up to 150%. Electrochemical impedance spectroscopy measurements showed that the charge transfer resistance increases with increased coating. The role of nafion coating in developing Mg based negative electrode materials is discussed. [1] Tan S., Shen Y., Sahin E. O., Noréus D., Ozturk T., "Activation behavior of an AB2 type metal hydride alloy for NiMH batteries" International Journal of Hydrogen Energy 41 (23), 9948-9953,2016

URI

https://hdl.handle.net/11511/84895

Collections

Unverified, Conference / Seminar

Suggestions

OpenMETU
Core

Design of Thin Film Membranes for Intermediate-Temperature Hydrogen Separation Pişkin, Fatih; Öztürk, Tayfur (2018-03-15) Abstract:0243] Design of Thin Film Membranes for Intermediate-Temperature Hydrogen Separation Fatih Pişkin1 , Tayfur Öztürk2 1 ENDAM, Center for Energy Materials and Storage Devices, Dept. of Metallurgical and Materials Engineering, Middle East Technical University, Ankara, Turkey Dept. of Metallurgical and Materials Engineering, Muğla Sıtkı Koçman University, Muğla, Turkey 2 ENDAM, Center for Energy Materials and Storage Devices, Dept. of Metallurgical and Materials Engineering, Middle East Technical Unive...
Optimum placement of high energy inductors for capacitive pulse power supplies GÜNGEN, İBRAHİM; Bostancı, Emine; Department of Electrical and Electronics Engineering (2021-9) Electromagnetic launcher (EML) systems convert electrical energy into mechanical energy. A large amount of energy must be supplied in a short time period to provide the necessary acceleration for the projectile. This type of energy is generally provided by capacitive pulsed power supplies (PPS). Many PPS units are connected in parallel to increase the total energy. Each module of a capacitive PPS includes high energy capacitor, shaping inductor, and semiconductors. The shaping inductors are air-core type in...
Experimental Investigation of the Original Project of Yukari Kalekoy Dam and Hydroelectric Power Plant Spillway Göğüş, Mustafa; Altan Sakarya, Ayşe Burcu; Köken, Mete (Elsevier BV; 2016-06-17) Hydraulic model tests of the spillway of Yukar Kalekoy Dam and Hydroelectric Power Plant (HPP) were carried out at Hydromechanics Laboratory of Middle East Technical University (METU), Ankara. In order to investigate the flow conditions in the approach channel, over the weir structure, around the spillway piers, along the spillway chute channels and after the flip buckets, and also to observe the performance of the aeration devices, a model of 1/70 length scale was constructed. The model area covers an abou...
Nonequilibrium plasma aerotaxy of size controlled GaN nanocrystals Üner, Necip Berker; Thimsen, Elijah (2020-02-01) High quality gallium nitride (GaN) nanocrystals (NCs) are promising materials in a wide range of applications including optoelectronics, photonics and biomedical devices. Unlike II-VI semiconductors, the synthesis of free-standing GaN NCs is not well-established, and there is a need for a synthesis platform that can provide GaN NCs with tunable size and photonic properties. In this work, we present a flexible gas-phase synthesis method that can deliver crystalline, free-standing, pure GaN NCs with controlle...
Electrochemical Performance of (MgCoNiZn)(1-x)LixO High-Entropy Oxides in Lithium-Ion Batteries Lökçü, Ersu; Toparlı, Çiğdem; Anık, Mustafa (2020-05-01) High-entropy oxides (HEOs), which are a new class of single-phase solid solution materials, have recently attracted significant attention as an anode material for lithium-ion batteries (LIBs). In this study, (MgCoNiZn)(1-x)LixO (x = 0.05, 0.15, 0.25, and 0.35) HEOs were synthesized and their electrochemical performances as the anode material were observed in LIBs. X-ray photoelectron spectroscopy (XPS) analysis showed that the increase in the lithium cation concentration causes generation of more oxygen vac...

Citation Formats

C. Eyövge, E. O. Şahin, and T. Öztürk, “Surface Modified Metal Hydrides as Negative Electrodes in NiMH Batteries,” 2018, vol. 1, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/84895.