# US 11,908,998 B2 · Liquid electrolyte for lithium metal battery

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- Number: US 11,908,998 B2
- Document ID: US11908998B2
- Status: Granted
- Kind: B2
- Application number: 16/922,332
- Filed: 2020-07-07
- Published: 2021-03-18
- Granted: 2024-02-20
- Earliest claimed: 2019-09-18
- Assignees: Apple Inc.
- Applicants: Apple Inc.
- Inventors: Alan A. Ritchie; Bernd Jurgen Neudecker; Karl M. Brown; Andrew Basile
- Web page: https://patentgrep.com/patent/US11908998B2

## CPC

- H01M 10/0567: characterised by the additives
- H01M 4/382: {Lithium (H01M4/405 takes precedence)}
- H01M 4/485: of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence)
- H01M 10/052: Li-accumulators
- H01M 10/0568: characterised by the solutes
- H01M 10/0569: characterised by the solvents
- H01M 2300/0025: Organic electrolyte
- H01M 2300/0028: characterised by the solvent
- H01M 2300/0045: Room temperature molten salts comprising at least one organic ion
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Liquid electrolytes for a lithium metal battery comprise an aprotic solvent, an ionic liquid, a lithium salt, 8 mol % to 30 mol % hydrofluoroether and up to 5 mol % additives. A molar ratio of the hydrofluoroether to the lithium salt is 0.22:1 to 0.83:1. The liquid electrolytes achieve at least a 50% improvement in cycle life over conventional electrolytes, extend capacity retention and delay increases in internal resistance.

## Claims

### Claim 1

A liquid electrolyte for a lithium metal battery, having the following composition:
LiF SI;
PYR13FSI;
DMC; and
13 mol %-21 mol % BTFE, wherein a molar ratio of BTFE to LiFSI is 0.22:1 to 0.83:1, a molar ratio of BTFE to DMC is 0.1:1 to 1:1, and a molar ratio of BTFE to a total of DMC and PYR13FSI is 0.15:1 to 0.5:1.

### Claim 2 (depends on 1)

The liquid electrolyte of claim 1, having the following composition:
30 mol % LiFSI+8 mol % PYR13FSI+45 mol % DMC+17 mol % BTFE.

### Claim 3 (depends on 1)

The liquid electrolyte of claim 1, wherein the LiFSI is 29 mol % of the liquid electrolyte.

### Claim 4 (depends on 1)

The liquid electrolyte of claim 1, wherein the PYR13FSI is 8 mol % of the liquid electrolyte.

### Claim 5 (depends on 1)

The liquid electrolyte of claim 1, wherein the DMC is 44 mol % of the liquid electrolyte.

### Claim 6 (depends on 1)

The liquid electrolyte of claim 1, wherein the BTFE is 19 mol % of the liquid electrolyte.

### Claim 7 (depends on 1)

The liquid electrolyte of claim 1, having the following composition:
29 mol % LiFSI+7 mol % PYR13FSI+44 mol % DMC+20 mol % BTFE.

### Claim 8 (depends on 1)

The liquid electrolyte of claim 1, having the following composition:
31 mol % LiFSI+9 mol % PYR13FSI+46 mol % DMC+14 mol % BTFE.

### Claim 9 (depends on 1)

The liquid electrolyte of claim 1, wherein the molar ratio of the BTFE to the LiFSI is 0.22:1 to 0.7:1.

### Claim 10 (depends on 1)

A lithium metal battery, comprising:
a cathode having a cathode current collector and a cathode active material comprising a lithium transition metal oxide;
an anode having an anode current collector and an anode active material comprising lithium metal; and
the liquid electrolyte of claim 1.