The electrical conductivity of Li2O2 is also influenced on the life time of the battery. There has been reported that a hole forming by the defect of Li palys a important role in the electrical conductivity of Li2O2. In this study, we model the formation of deposited Li2O2 layer as well as the forming process of the crystal defect, from the point of view of diffusion of Li2O2 cluster on the cathode surface. We calculate the sintering and diffusion processes of the discharge product Li2O2 on the carbon surface using a first-principles molecular dynamics method. We also examine how Li2O2 is deposited on the carbon surface. As a result, it deposited on the cluster shape up to the thickness of 3 " at 300 K. It is observed that the band gap of the Li2O2 is related to the thickness and it rapidly increases when it exceeds the 8 ". Diffusivity decreases in proportion to the increase in the size of Li2O2 cluster. Calculated diffusion coefficient of Li2O2 is revealed to the effect on the electrical conductivity of Li2O2. From these results, we investigate the effect of electrical conductivity of Li2O2 on the discharge curve analyzing by a numerical simulation. Conductivity shows little effect on the discharge curve. Therefore, It is concluded that a pore blocking is major factor of capacity of Li-O2 battery. This is the first study will be able to provide a breakthrough for the development of better Li-O2 battery.
Publications
| Sl. | Details |
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| 61 |
Journal: ECS Transactions, Publisher: Electrochemical Society, IF= 0.7 Abstract:In this work, we present results of periodic density functional theory study of the adsorption of carbon monoxide (CO) and hydroxyl (OH) on Pt2Ru3 alloy surface for different conformation of Pt and Ru. These results were compared with CO and OH adsorption on pure Pt and Ru surfaces. We find that the mixing of Pt by Ru leads to stronger bond of CO and OH to the Ru sites, whereas weaker bond notice of CO and OH to the Pt sites. We also analyze the effect of surface, sub surface and neighboring atoms effect on the adsorption of CO and OH on the Pt2Ru3 alloy surface. We notice that surface mixture with Pt and Ru atoms is more favourable adsorption sites for CO and OH than that of the homogeneous alloy surfaces. |
| 62 |
Journal: ECS Transactions, Publisher: Electrochemical Society, IF: 0.7 Abstract: It is well known that Pt-Ru alloy exhibits a promising catalytic activity for fuel cells. In this work we present density functional theory (DFT) study of the randomly mixed Pt-Ru alloys and discussed its stability based on the relative position of Pt and Ru atoms. The structures are modelled as five layer slabs because the ratio of surface atoms comparable with that for clusters about 3 nm sizes. The top surface fully covered by the Pt atom exhibits highest stability compared with other randomly mixed Pt-Ru alloys. We also discuss here the probability of Pt-Ru bond ratio (MPt-Ru/MPt-Ru+MPt-Pt) in the Pt-Ru alloy decreases with increasing the surface atom ratio (surface atom/Total number of atom), which is compared with available X-ray absorption fine structure data. |
| 63 |
Journal: ECS Transactions, Publisher: Electrochemical Society, IF:0.7 Abstract: In recent years, Li-O2 battery has received a great attention as a battery with high capacity and energy density. However, further studies are needed for the use of practical application to solve the issues must be overcome, such as lithium dendrites, side reactions of electrolyte, a blocking effect of diffusion path of oxygen and a corrosion of carbon. In this study we focus on, among from these issues, a blocking effect of diffusion path of oxygen in the cathode, which is the most important issue to realized the high capacity. Discharge products would inhibit oxygen diffusion in a cathode. Main discharge product is Li2O2. In this study we also focus on a dynamics of Li2O2. Li2O2 is generated from electrochemical reaction and will cover with the surface of the cathode resulting in the termination of further electrochemical reaction. Thus, the elucidation of dynamics of Li2O2 cluster on cathode surface is a key problem for the better understand of the life time of battery and the theoretical design of more improved Li-O2 battery. |
| 64 |
Journal Name: ECS Transactions, Publisher: Electrochemical Society, IF:0.7In the recent years, interest has grown in the development of anion exchange membranes (AEMs) for alkaline fuel cells, which have advantage over proton exchange membranes (PEM) fuel cells including cost and performance. In this work, we present molecular dynamics (MD) and first principles molecular dynamics (FPMD) studies to investigate transport mechanisms of OH- using quanternized multiblock copoly(arylene ether) (QPE) and poly (phthalazinone ether sulfone keton) (PPESK) anion exchange polymers. We report here Grotthus and vehicle mechanisms for OH- transport by molecular modeling. From our MD study for OH- diffusion in the QPE and PPESK, diffusion properties is comparable to experimental report and OH- transport mechanisms from FPMD simulation significantly differ with proton transport processes. |
| 65 |
Journal Name: Journal of Microsyst. Technologies, Publisher: Springer Nature IF:1.8 Abstract: For improving the tribological performance of hard disk drives, nanometer-thick perfluoropolyether (PFPE) lubricant films are generally treated with ultraviolet (UV) irradiation to bond them to the carbon overcoats of the disks. By modeling UV irradiation as an electron emission and attachment process, we investigate the UV bonding of nonfunctional PFPE Z and functional PFPE Zdol to hydrogenated and nitrogenated carbon surfaces with quantum chemical methods. Our calculation results show that, upon electron attachment, Z dissociates at its main chain to two fragments terminated by CF2CF2 and CF2O groups, whereas Zdol dissociates to a hydrogen fluoride and a fragment. The perfluoromethoxy oxygen in one of the Z fragments and the carbon radical and the hydrogen-truncated end group in the Zdol fragment interact strongly with sp2 and oxidized sites on carbon surfaces. Imine moieties on the CNx surface also contribute considerably to the UV bonding of Zdol. |
| 66 |
Journal: Catalysis Today Publisher: Elsevier IF:5.3 Quartiles Ranking:Q1 |
| 67 | Dr. Apurba Roy , Impact of extratropical cyclones, floods, and wildfires on firms’ financial performance in New Zealand Environmental Economics and Policy Studies ,04 May 2023 |
| 68 | Dr. Apurba Roy , Income and floods in New Zealand Environmental Hazards ,10 Nov 2022 |
| 69 | Dr. Apurba Roy , Impact of agriculture extension services on technical efficiency of rural paddy farmers in southwest Bangladesh Environmental Challenges ,02 Sep 2025 |
| 70 | Dr. Apurba Roy , Sudipa Basu , Determinants of Livelihood Diversification Under Environmental Change in Coastal Community of Bangladesh Asia-Pacific Journal of Rural Development ,26 Aug 2025 |