Search for: solid-electrolytes
Cycling performance of LiFePO4/graphite batteries and their degradation mechanism analysis via electrochemical and microscopic techniques, Article Ionics ; 2021 ; 09477047 (ISSN) ; Mosallanejad, B ; Mohammadzad, M ; Hosseini Hosseinabad, S. M ; Ramakrishna, S ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH 2021
In this work, cycling-induced aging occurring in 18650-type LiFePO4/graphite full cells at different C-rates is studied extensively. The mechanism of performance degradation is investigated using a combination of electrochemical and microstructural analyses. Half-cell studies are carried out after dismantling the full cells, using fresh and cycled LiFePO4 cathode and graphite anode to independently study them. The results show that the capacity of LiFePO4 electrodes is significantly recovered. The rate of capacity fading in the discharge state considered as irreversible capacity in the graphite is higher than LiFePO4 half cells, indicating a greater degradation in the performance of this...
A novel lifetime prediction method for lithium-ion batteries in the case of stand-alone renewable energy systems, Article International Journal of Electrical Power and Energy Systems ; Volume 103 , 2018 , Pages 115-126 ; 01420615 (ISSN) ; Dufo López, R ; Roshandel, R ; Bernal Agustin, J. L ; Sharif University of Technology
Elsevier Ltd 2018
This paper presents a mathematical formulation of lithium-ion batteries, including aging and temperature effects. The model is developed by integrating the simplified single particle model (SSPM) and reduced-order model (ROM) to predict solid electrolyte interphase growth (SEI). Results show agreement with the experimental data at 25 °C operating temperature and moderate cycling currents. A maximum error of 3.6% in finding the battery discharged Ah is observed in harsh operating conditions, including 60 °C and approaching the end of life of the battery. Due to the typical operating conditions of stand-alone renewable energy systems, more accurate estimations are expected. Finally, this...
Facile synthesis of titanium nitride-graphene nanocomposite and its improved rate-dependent electroactivity with respect to lithium storage, Article Materials Research Bulletin ; Volume 84 , 2016 , Pages 388-396 ; 00255408 (ISSN) ; Ghorbani, M ; Dolati, A ; Yashiro, H ; Sharif University of Technology
Titanium nitride/graphene nanocomposite as an anode material of lithium ion batteries has been fabricated through the reaction of TiCl4 and NaN3 in supercritical benzene medium followed by ammonia treating at 1000 °C for 10 h. The synthesized TiN/G nanocomposite depicts rate-dependent behavior in such a way that it shows specific capacity of 115 mAh g−1 when is cycled at higher rate (1.6 C) while it shows 76 mAh g−1 when is cycled initially at lower rate (0.2 C) and is subsequently subjected to higher rate (1.6 C). Moreover, TiN/G anode demonstrates capacity retention of 112%, 100%, and 70% after 250 cycles at charge/discharge rates of 1.6, 0.7, and 0.2 C, respectively. This unusual behavior...
Exact diffusion-induced elastic fields of a spherical core-shell nano-electrode li-ion battery via spectral theory, Article Journal of the Electrochemical Society ; Volume 167, Issue 13 , 2020 ; Shahryari, B ; Azizi, P ; Roumi, F ; Sharif University of Technology
IOP Publishing Ltd 2020
In Li-ion batteries the interface between the nano-size spherical core graphite and its surrounding solid electrolyte interphase (SEI) layer, just inside SEI is susceptible to damage. Thus, accurate determination of the associated elastic fields is one of the challenges in optimizing the lifetime and capacity of Li-ion batteries. The required precision is achieved by considering the core graphite which belongs to the crystal class D6h as homogeneous spherically isotropic and SEI layer as functionally graded (FG) isotropic material. Moreover, to account for the surface/interface effects appropriately the core-shell nano-structure subjected to the diffusion-induced time-dependent nonuniform...
Antimony doped SnO2 nanowire@C core–shell structure as a high-performance anode material for lithium-ion battery, Article Nanotechnology ; Volume 32, Issue 28 , 2021 ; 09574484 (ISSN) ; Abolhassani, R ; Hosseini, M ; Akbarnejad, E ; Mojallal, M. H ; Ghasemi, S ; Mohajerzadeh, S ; Sanaee, Z ; Sharif University of Technology
IOP Publishing Ltd 2021
SnO2 is considered as one of the high specific capacity anode materials for Lithium-ion batteries. However, the low electrical conductivity of SnO2 limits its applications. This manuscript reports a simple and efficient approach for the synthesis of Sb-doped SnO2 nanowires (NWs) core and carbon shell structure which effectively enhances the electrical conductivity and electrochemical performance of SnO2 nanostructures. Sb doping was performed during the vapor-liquid-solid synthesis of SnO2 NWs in a horizontal furnace. Subsequently, carbon nanolayer was coated on the NWs using the DC Plasma Enhanced Chemical Vapor Deposition approach. The carbon-coated shell improves the Solid-Electrolyte...
M.Sc. Thesis Sharif University of Technology ; Nemati, Ali
In recent years lithium-air batteries captured worldwide attention because of their high energy density. Solid state electrolytes is one of the main components of lithium-air batteries. Lithium almunium titanium phosphate(LATP) is a nasicon type ion conduction which may be of great potential as solid electrolyte. The object of this thesis was the preparation of LATP solid electrolyte which can be used in a lithium-air battery. To reach this goal LATP powder was synthesized using a solution-based method and an appropriate crystallization temperature was selected based on obtained results of X-ray diffraction analysis. In the next step solid electrolytes was prepared under different pressing...
Electrochemical and Microstructural Analysis of Aging Mechanism of 18650 LiFePO4/Graphite Li-ion Batteries under Different C-Rate and Temperature Conditions, M.Sc. Thesis Sharif University of Technology ; Asgari, Sirous
In this study, the aging of the LiFePO4/graphite cell was investigated in two different types of 18650 Li-ion batteries during cycling at various C-rates (0.5, 1, 2, 3, 4C) and high temperature under long-term cycling. An amount of 20% Capacity loss was considered as the end of the cycling. Batteries with a capacity of 1500 mAh after this capacity drop, experience 60, 120, 1502, and 2155 cycles, at the rates of 4, 3, 2, and 1C , and batteries with capacity of 1400 mAh was also 60, 360, 1100, 1000, and 805 cycles at a rate of 0.5C. Capacity decrease of the cell is in linear relationship with cycle number and the slope of the capacity-fading line increases with elevating current rate. Aging...
Synthesis and Characterization of Al-Doped Li7la3zr2o12 Garnet as a Solid Electrolyte for Li-Ion Batteries, M.Sc. Thesis Sharif University of Technology ; Faghihi Sani, Mohammad Ali
Li7La3Zr2O12 (LLZO) solid-state electrolyte is a very promising electrolyte for a variety of ion lithium solid-state batteries, due to high conductivity of Li ions at room temperature as well as its chemical stability with Li metal anode. LLZO phase has two tetragonal and cubic symmetries. The conductivity of the cubic phase is two times higher than that for the tetragonal phase. To stabilize the cubic phase at room temperature, 0.2, 0.25, and 0.3 mol% Aluminum was doped to LLZO solid-state electrolyte. This powder was synthesized by sol-gel combustion method at 1000˚C. The cubic phase and lack of impurity of the samples doped with 0.25 and 0.3% Aluminum were determined by X-ray Diffraction...
Article Applied Physics A: Materials Science and Processing ; Volume 120, Issue 3 , September , 2015 , Pages 869-874 ; 09478396 (ISSN) ; Tajabadi, F ; Jabbari, A ; Taghavinia, N ; Sharif University of Technology
Springer Verlag 2015
A simple gelating process is developed for the conventional acetonitrile-based electrolyte of dye solar cells, based on ethyl cellulose as the gelator. The electrolyte becomes quasi-solid-state upon addition of an ethanolic solution of ethyl cellulose to the conventional acetonitrile-based liquid electrolyte. The photovoltaic conversion efficiency with the new gel electrolyte is only slightly lower than with the liquid electrolyte, e.g., 6.5 % for liquid electrolyte versus 5.9 % for gel electrolyte with 5.8 wt% added ethyl cellulose. Electrolyte gelation has small effect on the ionic diffusion coefficient of iodide, and the devices are remarkably stable for at least 550 h under irradiation...
Study of the Surface Effect on the Behavior of a FG Multiphase Nano-sphere with Spherical Anisotropy due to Some Nonuniform Eigenstrain Field, M.Sc. Thesis Sharif University of Technology ; Mohammadi Shodja, Hossein
The elastic field is one of the challenges in optimizing the lifetime and capacity of the lithiumion batteries. Graphite nanoparticles have been widely used in Li-ion batteries, due to their mechanical, thermal and electrical properties. During the lithiation, chemical reactions occurred in the electrolyte, which forms a solid electrolyte interphase(SEI) in the surrounding of nanoparticles as well as stress fields inside the nanoparticles. Therefore, the purpose of this research is to examine the effects of the surface/interface on diffusion induced stresses(DIS) within core-shell nanosphere due to non-uniform distribution of eigenstrain fields. Due to the mechanical behavior of the phases,...
Study of the Surface Effect on the Behavior of a FG Multiphase Nano-Sphere with Spherical Anisotropy Due to some Nonuniform Eigenstrain Field, M.Sc. Thesis Sharif University of Technology ; Mohammadi Shodja, Hossein
The elastic field is one of the challenges in optimizing the lifetime and capacity of the lithium-ion batteries. Graphite nanoparticles have been widely used in Li-ion batteries, due to their mechanical, thermal and electrical properties. During the lithiation, chemical reactions occurred in the electrolyte, which forms a solid electrolyte interphase(SEI) in the surrounding of nanoparticles as well as stress fields inside the nanoparticles. Therefore, the purpose of this research is to examine the effects of the surface/interface on diffusion induced stresses(DIS) within core-shell nanosphere due to non-uniform distribution of eigenstrain fields. Due to the mechanical behavior of the phases,...
Article ASME 2013 7th Int. Conf. on Energy Sustainability Collocated with the ASME 2013 Heat Transfer Summer Conf. and the ASME 2013 11th Int. Conf. on Fuel Cell Science, Engineering and Technology ; July , 2013 ; 9780791855515 (ISBN) ; Hashemi, N ; Ashuri, M ; Montazami, R ; Advanced Energy Systems Division, Solar Energy Division ; Sharif University of Technology
We report improved performance of Li-ion polymer batteries through advanced gel polymer electrolytes (GPEs). Compared to solid and liquid electrolytes, GPEs are advantageous as they can be fabricated in different shapes and geometries; also ionic properties are significantly superior to that of solid and liquid electrolytes. We have synthetized GPE in form of membranes by trapping ethylene carbonate and propylene carbonate in a composite of polyvinylidene fluoride and N-methylpyrrolidinore. By applying phase-transfer method, we synthetized membranes with micro-pores, which led to higher ionic conductivity. The proposed membrane is to be modified further to have higher capacity, stronger...
Long term performance degradation analysis and optimization of anode supported solid oxide fuel cell stacks, Article Energy Conversion and Management ; Volume 133 , 2017 , Pages 20-30 ; 01968904 (ISSN) ; Roshandel, R ; Sharif University of Technology
Elsevier Ltd 2017
The main objective of this work is minimizing the cost of electricity of solid oxide fuel cell stacks by decelerating degradation mechanisms rate in long term operation for stationary power generation applications. The degradation mechanisms in solid oxide fuel cells are caused by microstructural changes, reactions between lanthanum strontium manganite and electrolyte, poisoning by chromium, carburization on nickel particles, formation of nickel sulfide, nickel coarsening, nickel oxidation, loss of conductivity and crack formation in the electrolyte. The rate of degradation mechanisms depends on the cell operating conditions (cell voltage and fuel utilization). In this study, the degradation...
Accurate analytical model for determination of effective diffusion coefficient of polymer electrolyte fuel cells by designing compact Loschmidt cells, Article Fuel ; Volume 199 , 2017 , Pages 551-561 ; 00162361 (ISSN) ; Abbasi, M ; Mansouri, M ; Kazemi, A ; Nakhaee, A ; Daryasafar, A ; Sharif University of Technology
Elsevier Ltd 2017
Effective diffusion coefficient is an important parameter which needs to be determined in different fields of study, such as cathode catalyst layers of PEM fuel. For this purpose, a Loschmidt diffusion cell can be used. When a porous medium is placed in Loschmidt apparatus, the effective gas diffusion coefficient (EGDC) of this section must be correlated by diffusion coefficient in absence of a porous medium. In the previous researches studying the Loschmidt diffusion cell, a simplifying infinite-length assumption was used in the analytical solution. Therefore, the solution is only applicable for a short time range, and this can result in high error. In order to overcome this challenge, the...
Nonisothermal two-phase modeling of the effect of linear nonuniform catalyst layer on polymer electrolyte membrane fuel cell performance, Article Energy Science and Engineering ; Volume 8, Issue 10 , 2020 , Pages 3575-3587 ; Jafari Mosleh, H ; Kavian, S ; Saffari Pour, M ; Mohammadi, O ; Aghanajafi, C ; Ahmadi, M. H ; Sharif University of Technology
John Wiley and Sons Ltd 2020
In this research, it is investigated to numerically evaluate the performance of a polymer electrolyte membrane fuel cell (PEMFC). The performance is investigated through the nonuniformity gradient loading at the catalyst layer (CL) of the considered PEMFC. Computational fluid dynamics is used to simulate a 2D domain in which a steady-state laminar compressible flow in two-phase for the PEMFC has been considered. In this case, a particular nonuniform variation inside the CL along the channel is assumed. The nonuniform gradient is created using a nonisothermal domain to predict the flooding effects on the performance of the PEMFC. The computational domain is considered as the cathode of PEMFC,...
Article Journal of Materials Science: Materials in Electronics ; Volume 32, Issue 5 , 2021 , Pages 6369-6378 ; 09574522 (ISSN) ; Golmohammad, M ; Soleimany Mehranjani, A. R ; Faghihi Sani, M ; Sharif University of Technology
Cubic phase Li7La3Zr2O12 (LLZO) is a promising solid electrolyte for next-generation Li-ion batteries. In this work, the combustion sol–gel technique is used to prepare an Al-doped LLZO solid electrolyte. The crystal structure is investigated, and the cubic phase is confirmed. Densification properties were investigated using SEM and optical dilatometry. The densification of the Al-doped sample takes place in two stages through two different shrinkage rates. Using 0.25 mol Al-dopant 94% relative density is achieved at 1100 °C. The effect of Al-doping on electrochemical properties is investigated in detail using AC impedance spectroscopy. The result indicates that the optimum concentration of...