Boronic Acid Electrode Additive for High-Nickel Li-Ion Cathodes
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Solution Overview
Problem
Lithium ion secondary batteries face issues such as degradation due to alkali components, electrolyte decomposition, and poor electrode winding properties, particularly with high-nickel positive active materials, leading to increased resistance, capacity loss, and difficulty in producing flat batteries like those for mobile devices.
Innovation Solution
A secondary battery electrode additive comprising a boronic acid derivative that coats the active material without high-temperature heat treatment, neutralizes alkali components, and suppresses electrolyte decomposition, enhancing adhesion strength and dispersibility of binders and conductive carbon materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-nickel positive active material is used to achieve high discharge capacity, then battery voltage and capacity are improved, but alkali components (LiOH, Li2CO3) on the surface cause gelling, corrosion, and gas generation leading to increased resistance and reduced battery life
Solution Approach 1:
The patent applies preliminary action by coating the surface of the high-nickel positive active material with a protective layer containing fluorinated cyclic carbonate and chain carbonate before battery assembly. This pre-coating prevents alkali components (LiOH, Li2CO3) from causing gelling, corrosion, and gas generation during subsequent charge-discharge cycles, thereby maintaining battery reliability while preserving high capacity performance
2Object-generated harmful factors
If fluorine gas treatment is used to fix LiOH as LiF and prevent gelling, then gelling is suppressed, but LiF increases internal resistance and fluorine corrodes the positive active material leading to capacity decrease
Solution Approach 1:
The patent changes the chemical parameters by replacing fluorine-based treatment with a carbonate-based coating system containing fluorinated cyclic carbonate and chain carbonate. This alternative chemistry achieves gelling suppression through different mechanisms (forming a protective barrier rather than converting LiOH to LiF), thereby avoiding the harmful side effects of LiF formation and fluorine corrosion while maintaining capacity retention
3Ease of manufacture
If phosphorous acid is added to change binder and conduction aid distribution to enhance winding properties, then electrode winding is improved, but lithium phosphate generated increases internal resistance and active material contact with electrolyte solution continues
Solution Approach 1:
The patent uses a composite coating material containing both fluorinated cyclic carbonate and fluorinated chain carbonate components. This composite structure provides multiple functions: it improves electrode winding properties through flexible chain structures while simultaneously forming a protective barrier that prevents active material contact with electrolyte solution and suppresses resistance increase, achieving both manufacturing ease and reliability
4Strength
If electrode foil thickness is increased to enhance strength and volume density, then electrode strength is improved, but the amount of positive active material per battery volume decreases leading to insufficient capacity
Solution Approach 1:
The patent employs a thin protective coating film containing fluorinated cyclic carbonate and chain carbonate on the positive active material surface. This thin film provides mechanical strength and flexibility improvement without significantly increasing electrode thickness, thereby maintaining high volume density and capacity per volume while achieving sufficient electrode strength for handling and winding
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The boronic acid derivative improves electrode winding properties, reduces resistance, and extends battery life by preventing corrosion and electrolyte decomposition, thus enhancing the overall performance and safety of lithium ion secondary batteries.
Implementation Method 1
a secondary battery electrode additive including a boronic acid derivative... capable of coating an active material
Implementation Method 2
can neutralize an alkali component and suppress decomposition of an electrolyte solution
Data Source
AI summary
Provided is a secondary battery electrode additive with which an active material can be coated without heat treatment that is performed at a high temperature for a long period of time, an alkaline component can be neutralized, and the decomposition of an electrolytic solution can be suppressed. For example, provided is a secondary battery electrode additive comprising a boronic acid derivative represented by formula (5).(In the formula, R1-R5 each independently represent a hydrogen atom, an alkyl group, an ester group, a glycol chain, an alkoxy group, or a hydroxy group, and R6 represents a hydrogen atom, a methyl group, or an ethyl group.)