Development and characterization of high energy cathode materials for lithium-ion batteries

Download
2013
Büyükburç, Atıl
The aim of this thesis is to produce high energy cathode materials based on LiCoO2 materials with the general formula LiCo1-xMxO2 and LiCo1-y-xMxNyO2. In order to achieve this formula, less exploited doping elements such as Mo, Cr and W will be used as well as Mn. During the study, the parameters of the processes which are solution preparation, freeze drying and calcination are optimized. According to the results, 24 hours of freeze drying is enough for drying the samples. Calcination at lower (< 700°C) temperatures as well as higher temperatures (> 800°C) do not yield single phase LiCoO2. It is also determined that, holding pH around 10.75 and Li:Co ratio are very important for having single phase LiCoO2. XRD, SEM and SEM-EDX are used for structural analyses. ICP and XPS are used for chemical analysis. For electrochemical characterization, galvanostatic charge-discharge tests, CV and EIS are applied. The results have shown that the sample containing 1 mole% W and 1 mole% Mn has the best electrochemical performance among the other samples. The reason for the electrochemical superiority of this sample is due to the different surface chemistry.

Suggestions

Development and characterization of high power density cathode materials for lithium-ion batteries
Doğu, Şafak; Aydınol, Mehmet Kadri; Evis, Zafer; Department of Micro and Nanotechnology (2015)
In this thesis, facile and cost efficient aqua based synthesis method is developed to synthesize power dense and fast rechargeable LiFePO4 cathode materials. In order to obtain nano sized crystal morphology, nucleation controlled techniques were studied on precursor synthesis. These techniques are freeze (cryogenic) drying with co-precipitation and ultrasound assisted sub-sequential precipitation with vacuum drying at low temperatures (<350 K). In co-precipitation with freeze drying synthesis, star-like pla...
Application of ab initio methods to secondary lithium batteries
Aydınol, Mehmet Kadri; Ceder, G. (1998-01-01)
Ab initio methods have started to be widely used in materials science for the prediction of properties of metals, alloys and compounds. These methods basically require only the atomic numbers of the constituent species. Such methods not only provide us with predictions of some of the properties of the material (even before synthesizing it) but also help us in understanding the phenomena that control those properties. The use of ab initio methods in the field of electrochemistry is, however, quite recent and...
Development of non-noble Co–N–C electrocatalyst for high-temperature proton exchange membrane fuel cells
Eren, Enis Oğuzhan; Özkan, Necati; Devrim, Yılser (Elsevier BV, 2020-11-27)
© 2020 Hydrogen Energy Publications LLCThe development of a non-noble Co–N/MWCNT (MWCNT = multi-walled carbon nanotubes) electrocatalyst is achieved through the high-temperature pyrolysis method and successfully characterized by five-step physico-chemical analysis. By utilizing high-resolution analytical surface characterization methods, the chemical states of elements are determined, and the presence of Co-Nx sites is confirmed. ORR activity of a Co–N/MWCNT is found to be auspicious. The maximum number of ...
Preparation and characterization of a new CdS-NiFe2O4/reduced graphene oxide photocatalyst and its use for degradation of methylene blue under visible light irradiation
Bagherzadeh, Mojtaba; Kaveh, Reyhaneh; Özkar, Saim; AKBAYRAK, SERDAR (Springer Science and Business Media LLC, 2018-10-01)
In this paper, CdS nanoparticles as a visible light active photocatalyst were coupled by NiFe2O4 and reduced graphene oxide (rGO) to form CdS-NiFe2O4/rGO nanocomposite by facile hydrothermal methods. The CdS-NiFe2O4/rGO nanocomposite shows enhanced photocatalytic activity for the degradation of methylene blue (MB) under visible light illumination. In addition to improved photocatalytic performance, this prepared nanocomposite shows increased photostability and is magnetically separable from the aqueous medi...
Fabrication and characterization of photocrosslinked phase change materials by using conventional and terahertz spectroscopy techniques
Aytan, Emre; Aytekin, Yusuf Samet; Esentürk, Okan; KAHRAMAN, MEMET VEZİR (2019-12-01)
A series of novel photocrosslinked shape-stabilized phase change materials (PCMs) based on tetradecanol and lauric acid have been prepared by UV technique for the purpose of thermal energy storage applications. Both lauric acid and tetradecanol were reacted with glycidyl methacrylate to form acrylated structures for covalently integrate into polyurethane (PU) based UV matrix to prevent leakage problem. The heating process phase change enthalpy is measured between 9 and 77 J/g, and the freezing process phase...
Citation Formats
A. Büyükburç, “Development and characterization of high energy cathode materials for lithium-ion batteries,” Ph.D. - Doctoral Program, Middle East Technical University, 2013.