Aqueous secondary battery

Patent metadata

Field	Value
Publication number	US-11569532-B2
Application number	US-202016811204-A
Country	US
Kind code	B2
Filing date	Mar 6, 2020
Priority date	Feb 14, 2020
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

An aqueous secondary battery including: a positive electrode; a negative electrode; a separator; and an aqueous electrolytic solution including water and a metal salt represented by Chemical Formula 1 AxDy and having molality of about 5 M to about 40 M wherein in Chemical Formula 1, A is at least one metal ion selected from a sodium ion, a potassium ion, a magnesium ion, a calcium ion, a strontium ion, a zinc ion, or a barium ion, D is at least one type of atomic group ion selected from Cl−, SO42−, NO3−, ClO4−, SCN−, CF3SO3−, C4F3SO3−, (CF3SO2)2N−, AlO2−, AlCl4−, AsF6−, SbF6−, BR4−, and PO2F2−, and 0<x≤2, and 0<y≤2.

First claim

What is claimed is:

1. An aqueous secondary battery as a sodium secondary battery comprising
a positive electrode comprising at least one positive active material selected from the group consisting of Na 4 Fe 3 (PO 4 ) 2 (P 2 O 7 ), Na 4 MnFe 2 (PO 4 ) 2 (P 2 O 7 ), Na 4 Mn 2 Fe(PO 4 ) 2 (P 2 O 7 ) and Na 4 Mn 3 (PO 4 ) 2 (P 2 O 7 );
a negative electrode comprising at least one negative active material selected from the group consisting of a sodium metal, a sodium metal based alloy, and a sodium insertion compound;
a separator; and
an aqueous electrolyte solution comprising water and NaClO 4 and having molality greater than 10 m to 40 m,
wherein the aqueous electrolyte solution comprises a crystalline hydrate, and the crystalline hydrate comprises a portion of a sodium ion and a perchlorate ion from NaClO 4 that constitutes a coordination with water molecules, and
wherein the sodium ion and the perchlorate ion forming the crystalline hydrate is in form of solvent-separated ion pairs, contact ion pairs and aggregated cation-anion pairs, and a mole fraction of the contact ion pairs relative to the aggregated cation-anion pairs is greater than or equal to about 50% based on a total amount of the sodium ion and the perchlorate ion that are ionized in the aqueous electrolyte solution.

2. The aqueous secondary battery of claim 1 , wherein the aqueous electrolyte solution has ion conductivity of greater than or equal to about 40 mS/cm.

3. The aqueous secondary battery of claim 1 , wherein when the aqueous secondary battery is charged, a passivation film comprising the sodium ion is formed on the surface of the negative electrode.

4. The aqueous secondary battery of claim 3 , wherein the passivation film has an average thickness of about 1 nm to about 10 nm.

5. The aqueous secondary battery of claim 3 , wherein the passivation film comprises at least one selected from the group consisting of NaOH and Na 2 CO 3 .

6. The aqueous secondary battery of claim 1 , wherein an electrochemical stability window of the aqueous secondary battery obtained through cyclic voltammetry belongs to a voltage range of greater than about 1.23 V.

7. The aqueous secondary battery of claim 1 , wherein a width of an electrochemical stability window of the aqueous electrolyte solution obtained through cyclic voltammetry is about 1 V to about 4 V.

Assignees

• Seoul Nat Univ R&Db Foundation

Inventors

• Kang Kisuk
• Lee Myeong Hwan
• Kim Sung Joo

Classifications

• C01P2006/40

  Electric properties · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• C01D9/00

  Nitrates of sodium, potassium or alkali metals in general {(preparation as fertilizers or of fertilizers containing them C05D5/00)} · CPC title

• H01M2300/0005

  Acid electrolytes · CPC title

• H01M2004/028

  Positive electrodes · CPC title