Two-Liquid Positive Electrode Slurry for Stable Irreversible Additives

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Solution Overview

Problem

Lithium secondary batteries face challenges in achieving high dispersibility and electrical properties when using small amounts of irreversible additives due to structural instability and loss during the manufacturing process, which affects charging and discharging efficiency and safety.

Innovation Solution

A positive electrode slurry with a two-liquid composition, including a first liquid with a viscosity of 5,000 to 8,000 cps and a second liquid with a viscosity of 8,000 to 10,000 cps, containing a positive electrode additive represented by Chemical Formula LipCo(1-q)M1qO4, which ensures excellent dispersibility and minimizes additive loss, thereby improving electrical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a small amount of irreversible additive (less than 5 wt %) is used in the positive electrode slurry, then the irreversibility of the lithium secondary battery is reduced, but the dispersibility of the additive deteriorates and loss amount increases due to scattering during manufacturing

Engineering Contradiction:

Improveirreversibility of lithium secondary batteryVSAvoiddispersibility of irreversible additive

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent changes the physical parameters of the irreversible additive by controlling particle size distribution (D10: 0.5-2.0 μm, D50: 3.0-5.0 μm, D90: 6.0-10.0 μm) and chemical composition (Li6-p-qM1pCo(1-q)O4 with specific element substitutions), enabling effective use at low concentrations (0.1-5 wt %) while maintaining dispersibility and reducing loss during manufacturing

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite irreversible additives where traditional Li6CoO4 is modified by incorporating elements such as Li, Ni, Mn, Zn, Cu, Fe, Co, Al, Ti, Zr, or B to create Li6-p-qM1pCo(1-q)O4 composites. This composite structure improves both dispersibility in the slurry and reduces particle loss during electrode manufacturing while maintaining the desired electrochemical function

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If a large amount of irreversible additive is used in the positive electrode, then the capacity is increased, but structural instability causes oxygen gas generation and safety issues

Engineering Contradiction:

Improvecapacity of lithium secondary batteryVSAvoidsafety of lithium secondary battery

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the irreversible additive by substituting elements in the Li6-p-qM1pCo(1-q)O4 structure, which stabilizes the crystal structure and suppresses oxygen release during charging, enabling safe use of higher amounts (up to 5 wt %) to increase battery capacity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the potentially harmful structural instability and oxygen generation of traditional Li6CoO4 into a benefit by using element-substituted composites. The substituted elements stabilize the structure and suppress oxygen release, transforming a safety hazard into a stable, high-capacity electrode material

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Quantity of substance

If conventional irreversible additives like Li6CoO4 are used, then the capacity is increased, but structural instability generates oxygen gas during charging

Engineering Contradiction:

Improvecapacity contribution of irreversible additiveVSAvoidoxygen gas generation during charging

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by substituting elements (Li, Ni, Mn, Zn, Cu, Fe, Co, Al, Ti, Zr, or B) into the Li6CoO4 structure to create Li6-p-qM1pCo(1-q)O4, which stabilizes the crystal structure and suppresses oxygen evolution during charging while maintaining capacity contribution

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates composite irreversible additives by combining Li6CoO4 with element substitutions, forming Li6-p-qM1pCo(1-q)O4 composites that maintain the high capacity contribution of Li6CoO4 while eliminating its harmful oxygen generation through structural stabilization

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS20230268499A1Positive Electrode Slurry and Positive Electrode for Lithium Secondary Battery Using the Same

Publication Date: 2023.08.24 LG ENERGY SOLUTION LTD

AI summary

Provided is a positive electrode slurry for a positive electrode for a lithium secondary battery, which is manufactured using the same. The positive electrode slurry is composed of a two-liquid type composition, contains the positive electrode additive represented by Chemical Formula 1 (LipCo(1-q)M1qO4), which is used as an irreversible additive, in a large amount, and contains the first liquid whose viscosity is adjusted within a specific range (i.e. 5,000 to 8,000 cps). Thus, not only is there an advantage in that the dispersibility and workability of the positive electrode additive are excellent, but also since it is possible to suppress side reactions while minimizing the loss of the positive electrode additive contained in the positive electrode slurry, the state stability of the positive electrode slurry can be improved, and thus the electrical properties of the positive electrode manufactured using the positive electrode slurry are excellent.