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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

High energy density and durable pouch-cell graphite-based dual ion battery using concentrated hybrid electrolytes

Sabaghi, Davood, Wang, Gang, Mikhailova, Daria, Morag, Ahiud, Ahmad, Li, Dongqi, Khosravi Haji Vand, Saman, Yu, Minghao, Feng, Xinliang, Shaygan Nia, Ali 23 May 2024 (has links)
Graphite-based dual-ion batteries (GDIBs) represent a promising battery concept for large-scale energy storage on account of low cost, high working voltage, and sustainability. The electrolyte concentration plays a critical role in determining the energy density and cycle life of GDIBs. However, the concentrated electrolytes show low Lithium ions (Li+) transport kinetics, reducing their intercalation and solid electrolyte interface (SEI) formation abilities. Moreover, the GDIBs in the high cut-off voltage suffer from electrolyte degradation, and corrosion of the current collector. Herein, we report a highly concentrated electrolyte formulation based on hybrid lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonyl)imide (LiFSI) salts with a super-wide electrochemical stability window (6 V) and the ability to form SEI and passivation layer on graphite anode and current collector, respectively. By regulating the concentrated LiFSI electrolyte with LiPF6 and solvent additive, the coulombic efficiency of the graphite cathode can be further improved to ∼98%. As a result, GDIB pouch cell exhibits a capacity of 21 mAh g−1 (cell level) at 50 mA g−1, and 98.2% capacity retention after 300 cycles. The resultant battery offers an energy density of 90.3 Wh kg−1, along with a high energy efficiency of 87% and average discharge voltage of 4.3 V.
2

TERMISKT SMARTA HANTERINGSSYSTEM FÖR LITIUMJONBATTERIER : Analys av litium-jonbatteriets termiska beteende

Kohont, Alexander, Isik, Roger Can January 2021 (has links)
Batteries play an important role in a sustainable future. As the development for better andsmarter batteries continues, new areas of use emerge boosting its demand. Controlling thetemperature of a battery cell is a vital objective to ensure its longevity and performance. Bothcooling and heating methods can be applied to keep the temperature within a certain rangedepending on its need. This study will review the technical aspects of lithium-ion batteries,observe the different thermal management systems and cooling methods, and lastly examinethe required cooling flow needed for a battery cell to prevent its temperature from rising tocritical levels during its discharge. Using CFD ANSYS Fluent as a simulation tool, the resultsshow that different charging rates, in terms of C-rate, require different rates of mass flow tocontrol the temperature. Simulating the cell with natural convection, the cell peaks at hightemperatures even at lower C-rates, reaching up to 36,4°C and 48,8°C for 1C and 2C,respectively. Applying the cooling method with a flow rate of 0,0077kg/s reduces thetemperature significantly, resulting in temperatures of 26,95°C and 31,27°C for 1C and 2C,respectively.

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