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JP-7856114-B2 - secondary battery

JP7856114B2JP 7856114 B2JP7856114 B2JP 7856114B2JP-7856114-B2

Inventors

  • 井原 将之

Assignees

  • 株式会社村田製作所

Dates

Publication Date
20260511
Application Date
20221223
Priority Date
20211224

Claims (8)

  1. Positive electrode and, A negative electrode containing a negative electrode active material layer, The system comprises an electrolyte solution containing an electrolyte salt, The aforementioned negative electrode active material layer contains a carbon material, The thickness of the negative electrode active material layer is 30 μm or more and 80 μm or less. The volume density of the negative electrode active material layer is 1.4 g/ cm³ or more and 1.8 g/ cm³ or less. The electrolyte salt comprises an imid anion, and the imid anion comprises at least one of a first imid anion represented by formula (1) and a second imid anion represented by formula (2). The electrolyte further comprises lithium hexafluoride phosphate, The electrolyte salt comprises a cation and the imid anion, The lithium hexafluoride phosphate comprises lithium ions and hexafluoride phosphate ions. The sum of the cation content in the electrolyte and the lithium ion content in the electrolyte is 0.7 mol/kg or more and 2.2 mol/kg or less. The ratio of the number of moles of the hexafluoride phosphate ion in the electrolyte to the number of moles of the imido anion in the electrolyte is 13 mol% or more and 6000 mol% or less. Secondary battery. (Each of R1 and R2 is either a fluorine group or a fluorinated alkyl group. Each of W1, W2, and W3 is either a carbonyl group (>C=O), a sulfinyl group (>S=O), or a sulfonyl group (>S(=O) ² ).) (Each of R3 and R4 is either a fluorine group or a fluorinated alkyl group. Each of X1, X2, X3, and X4 is either a carbonyl group, a sulfinyl group, or a sulfonyl group.)
  2. The negative electrode further comprises styrene-butadiene rubber, The secondary battery according to claim 1.
  3. The carbon material contains graphite, The interplanar spacing of the (002) planes of the graphite, as measured by X-ray diffraction, is 0.3372 nm or less. The secondary battery according to claim 1.
  4. The aforementioned electrolyte salt contains light metal ions as cations. The secondary battery according to claim 1.
  5. The aforementioned light metal ions include lithium ions. The secondary battery according to claim 4.
  6. The content of the electrolyte salt in the electrolyte solution is 0.2 mol/kg or more and 2 mol/kg or less. A secondary battery according to any one of claims 1 to 5.
  7. The electrolyte further comprises at least one of lithium hexafluoride phosphate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide, lithium bis(oxalato)borate, and lithium difluorophosphate. A secondary battery according to any one of claims 1 to 5.
  8. Lithium-ion rechargeable batteries, A secondary battery according to any one of claims 1 to 5.

Description

This technology relates to secondary batteries. With the widespread use of various electronic devices such as mobile phones, development of rechargeable batteries is progressing as a power source that is small, lightweight, and provides high energy density. These rechargeable batteries contain an electrolyte along with a positive electrode and a negative electrode, and various studies are being conducted on the configuration of these batteries. Specifically, the electrolyte contains an imide compound represented as R F 1 - S(=O) 2 - NH - S(=O) 2 - NH - S(=O) 2 - R F 2 (see, for example, Patent Document 1). Furthermore, the electrolyte salt of the electrolyte contains an imide anion represented as F - S(=O) 2 - N - - C(=O) - N - - S(=O) 2 - F or F - S(=O) 2 - N - - S(=O) 2 - C 6 H 4 - S(=O) 2 - N - - S(=O) 2 - F (see, for example, Non-Patent Documents 1 and 2). Chinese Patent No. 102786443 Specification Faiz Ahmed et al., “Novel divalent organo-lithium salts with high electrochemical and thermal stability for aqueous rechargeable Li-Ion batteries”, Electrochimica Acta, 298, 2019, 709-716Faiz Ahmed et al., “Highly conductive divalent fluorosulfonyl imide based electrolytes improving Li-ion battery performance: Additive potentiating”, Journal of Power Sources, 455, 2020, 227980 Although various studies have been conducted on the configuration of secondary batteries, their battery characteristics are still not sufficient, and there is room for improvement. There is a need for a secondary battery that can achieve excellent battery characteristics. A secondary battery according to one embodiment of this technology comprises a positive electrode, a negative electrode including a negative electrode active material layer, and an electrolyte containing an electrolyte salt. The negative electrode active material layer contains a carbon material, has a thickness of 30 μm or more and 100 μm or less, and has a volume density of 1.4 g/ cm³ or more and 2 g/ cm³ or less. The electrolyte salt contains an imid anion, which includes at least one of a first imid anion represented by formula (1), a second imid anion represented by formula (2), a third imid anion represented by formula (3), and a fourth imid anion represented by formula (4). (Each of R1 and R2 is either a fluorine group or a fluorinated alkyl group. Each of W1, W2, and W3 is either a carbonyl group (>C=O), a sulfinyl group (>S=O), or a sulfonyl group (>S(=O) ² ).) (Each of R3 and R4 is either a fluorine group or a fluorinated alkyl group. Each of X1, X2, X3, and X4 is either a carbonyl group, a sulfinyl group, or a sulfonyl group.) (R5 is a fluorinated alkylene group. Y1, Y2, and Y3 are each one of a carbonyl group, a sulfinyl group, or a sulfonyl group.) (Each of R6 and R7 is either a fluorine group or a fluorinated alkyl group. R8 is either an alkylene group, a phenylene group, a fluorinated alkylene group, or a fluorinated phenylene group. Each of Z1, Z2, Z3, and Z4 is either a carbonyl group, a sulfinyl group, or a sulfonyl group.) According to one embodiment of the secondary battery of this technology, the negative electrode active material layer of the negative electrode contains a carbon material, the thickness of the negative electrode active material layer is 30 μm or more and 100 μm or less, the volume density of the negative electrode active material layer is 1.4 g/ cm³ or more and 2 g/ cm³ or less, and the electrolyte salt of the electrolyte solution contains at least one of the first imid anion, second imid anion, third imid anion, and fourth imid anion as an imid anion, so that excellent battery characteristics can be obtained. Furthermore, the effects of this technology are not necessarily limited to those described herein, but may include any of the series of effects related to this technology described later. This is a perspective view showing the configuration of a secondary battery in one embodiment of this technology.This is a cross-sectional view showing the configuration of the battery element shown in Figure 1.This is a block diagram showing the configuration of an example application of a secondary battery. An embodiment of this technology will be described in detail below with reference to the drawings. The order of description is as follows. 1. Rechargeable Batteries 1-1. Structure 1-2. Operation 1-3. Manufacturing Method 1-4. Function and Effects 2. Modifications 3. Applications of Rechargeable Batteries <1. Secondary battery> First, we will describe a secondary battery according to one embodiment of this technology. The secondary battery described here is a secondary battery that obtains its capacity by utilizing the intercalation and deintercalation of electrode reactants, and is equipped with an electrolyte along with a positive electrode and a negative electrode. In this secondary battery, the charging capacity of the negative electrode is greater than the discharging capacity of the positive electrode. That is, the electrochemical