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Hybrid Aqueous/Nonaqueous Electrolyte for Ca-Ion Batteries

Noorsina, Saba | 2023

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 56796 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Sadrnezhaad, Khatiboleslam; Yoozbashizadeh, Hossein
  7. Abstract:
  8. Water-in-salt (WIS) electrolytes with a wide electrochemical stability window (ESW) have made great progress in the field of aqueous batteries and capacitors. However, the slow diffusion of metal ions, such as lithium or calcium, has limited the use of these devices. Meanwhile, adding an organic co-solvent can improve the penetration of metal ions in salt water electrolytes. This electrolyte category, which has also used organic solvent in addition to water, is called organic/aqueous hybrid electrolyte modification. Since the effect of organic solvent on the performance of aqueous electrolyte in calcium batteries has not been investigated so far, in this research the physical and chemical properties of aqueous/non-aqueous hybrid electrolyte Ca(NO3)2.4H2O/H2O/ACN including conductivity, flammability, viscosity, ESW, and Raman spectroscopy were investigated. has taken. The results show that the addition of acetonitrile at the rate of 10% by weight to Ca(NO3)2.4H2O/H2O aqueous electrolyte significantly increases the conductivity, restricts the O-H bond, reduces the free O-H bond, and strongly hydrates the Ca2+ ion. Also, compared to organic electrolytes, this hybrid electrolyte is highly safe due to the presence of water, so the electrolyte will not be flammable at a weight percentage of less than 40% of acetonitrile. In addition, galvanostatic charge and discharge tests have also been performed in order to check the electrochemical stability of cathode and conventional anodes used in calcium batteries. The results show that the CuHCF cathode with an initial capacity of 188 mAh g-1 in the presence of Ca(NO3)2.4H2O/H2O/ACN hybrid electrolyte maintained 85% of its initial capacity after 100 cycles. Also, by increasing the charging rate from 0.2 A g-1 to 5 A g-1, this cathode has maintained 70% of its capacity
  9. Keywords:
  10. Acetonitrile ; Water-In-Salt (WIS)Electrolytes ; Organic/Aqueous Hybrid Electrolyte ; Calcium-Ion Battery ; Organic Solvent

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