Nonaqueous Battery Cathode Additive for Oxygen Pressure Control
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Solution Overview
Problem
Nonaqueous electrolyte secondary batteries face safety issues due to internal pressure increases caused by oxygen generation and oxidative decomposition during high-temperature events, such as internal short circuits, which can lead to battery case damage.
Innovation Solution
Incorporating a positive electrode additive with a particulate base material and an organic compound group bonded via a X—O-A covalent bond, where X is Si or Ti, and the organic compound group has 2 or more carbon atoms, to absorb and consume oxygen generated from the composite oxide, thereby suppressing internal pressure increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a composite oxide containing lithium and transition metal is used as positive electrode active material, then high energy density and high output are achieved, but oxygen is generated during high-temperature events causing internal pressure increase and safety issues
Solution Approach 1:
An additive comprising a particulate base material with organic compound groups bonded via X—O-A covalent bonds (where X is Si or Ti, A is base material element) is introduced as an intermediary substance. This additive preferentially reacts with oxygen generated from the composite oxide during high-temperature events, acting as a mediator that protects the electrolyte from oxidative decomposition and controls internal pressure increase, thereby resolving the safety issue while maintaining the high output performance of the composite oxide cathode material.
Solution Approach 2:
The oxygen generated from the composite oxide during high-temperature events, which is normally a harmful factor causing electrolyte decomposition and safety issues, is converted into a beneficial effect by having it preferentially react with the additive. The additive consumes this harmful oxygen through controlled reactions, transforming the potentially dangerous oxygen generation into a protective mechanism that prevents more severe damage to the battery system.
2Power
If the positive electrode mixture contains composite oxide and traditional additives, then electrochemical performance is maintained, but oxidative decomposition of nonaqueous electrolyte occurs during high-temperature events
Solution Approach 1:
The additive with X—O-A covalent bonds serves as a protective intermediary between the composite oxide and the nonaqueous electrolyte. During high-temperature events, the additive preferentially reacts with oxygen released from the composite oxide, forming a protective barrier that prevents direct contact between oxygen and the electrolyte, thereby eliminating oxidative decomposition while maintaining electrochemical performance.
Solution Approach 2:
The invention changes the chemical composition and surface properties of the additive by using specific X—O-A covalent bond structures (where X is Si or Ti). This parameter change in the additive's chemical structure gives it superior oxygen reactivity compared to traditional additives, enabling it to effectively scavenge oxygen and prevent electrolyte oxidation without compromising electrochemical performance.
3Quantity of substance
If internal pressure increases due to oxygen generation and gas production, then battery case damage may occur, but no effective pressure control mechanism is present
Solution Approach 1:
The additive is pre-introduced into the positive electrode mixture before battery assembly. During high-temperature events, this pre-positioned additive immediately reacts with generated oxygen, preventing the accumulation of gaseous products. This preliminary protective action controls internal pressure before it can reach levels that would compromise battery case integrity.
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 additive effectively absorbs oxygen, preventing oxidative decomposition of the nonaqueous electrolyte and reducing the risk of battery case damage by stabilizing the internal pressure, thus enhancing battery safety.
Implementation Method 1
the additive effectively absorbs oxygen, preventing oxidative decomposition of the nonaqueous electrolyte
Implementation Method 2
the nonaqueous electrolyte may be oxidized and decomposed by oxygen generated from the positive electrode
Implementation Method 3
an organic compound group fixed to the surface of the base material by a covalent bond; the covalent bond includes a X—O-A bond
Data Source
AI summary
The nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode includes a positive electrode mixture containing a positive electrode active material and an additive. The positive electrode active material contains a composite oxide containing lithium and a transition metal. The additive contains a particulate base material, and an organic compound group fixed to the surface of the base material by a covalent bond. The covalent bond contains a X—O-A bond. The element X is bonded to the organic compound group, and is at least one selected from the group consisting of Si and Ti. The element A is an element constituting the base material. The organic compound group has 2 or more carbon atoms.