Positive Electrode Additive for High-Voltage Lithium Battery Stability
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Solution Overview
Problem
Lithium secondary batteries experience safety issues such as swelling due to gas generation when used continuously or exposed to high temperatures, which is exacerbated by the degradation of the electrolyte at high voltages, affecting their high-capacity and high-power performance.
Innovation Solution
Incorporation of a positive electrode additive with cyclic sulfonic ester or cyclic sulfate structures that form a robust electrolyte-electrode interface by reacting with lithium byproducts, suppressing oxygen release and side reactions, thereby enhancing structural stability and reducing gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium secondary batteries are operated at high voltage to improve energy density, then energy density is improved, but electrolyte degradation accelerates causing gas generation and safety issues
Solution Approach 1:
The patent introduces a positive electrode additive as an intermediary substance that mediates between the high-voltage operating conditions and the electrolyte. This additive forms a protective interface layer that prevents direct harmful interactions between the electrolyte and electrode at high voltages, thereby allowing high energy density operation while maintaining safety through the protective intermediary layer
Solution Approach 2:
The positive electrode additive performs preliminary protective action by forming a stable interface layer before electrolyte degradation can occur. This pre-formed protective layer prevents the subsequent harmful effects of electrolyte decomposition and gas generation, enabling the battery to operate safely at high voltages without experiencing the adverse effects that would normally occur
2Productivity
If lithium secondary batteries are used continuously or exposed to high temperature, then power supply capability is improved, but gas generation occurs causing swelling and safety problems
Solution Approach 1:
The positive electrode additive serves as a protective intermediary that forms a stable interface layer between the electrode and electrolyte. This intermediary layer prevents direct harmful reactions between the electrolyte and electrode during continuous operation or high-temperature exposure, thereby suppressing gas generation while maintaining continuous operation capability
Solution Approach 2:
The additive provides beforehand cushioning by forming a protective interface layer in advance that cushions against harmful effects during continuous operation or high-temperature exposure. This pre-formed protective layer absorbs and mitigates the harmful effects of electrolyte degradation, preventing gas generation while allowing continuous operation
3Reliability
If positive electrode additive with cyclic sulfonic ester or cyclic sulfate structure is added, then interface stability and durability are improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of the positive electrode additive to include specific cyclic sulfonic ester or cyclic sulfate groups. This structural parameter change enables the additive to form stable interface layers that improve reliability, while the selection of specific chemical parameters allows for controlled manufacturing processes
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 positive electrode additive forms a durable interface, improving the cycle characteristics and reducing gas generation, leading to enhanced long-term durability and performance of lithium secondary batteries.
Implementation Method 1
the compound of Formula 1 or Formula 2, which is the positive electrode additive directly added into the positive electrode, reacts with a lithium byproduct on the surface of the positive electrode, and a ring opening reaction occurs at sulfur-containing rings in the additive of Formula 1 or Formula 2, forming a film on the surface of the positive electrode
Implementation Method 2
the release of oxygen from a positive electrode active material is suppressed, which improves the structural stability of the positive electrode active material
Implementation Method 3
a side reaction of electrolyte on the surface of the positive electrode is suppressed
Data Source
AI summary
A positive electrode of a secondary battery includes: a positive electrode active material layer, which in turn includes a positive electrode active material, a conductive material, a binder, and a positive electrode additive. The positive electrode additive includes substituents with a cyclic sulfonic ester (sultone) or cyclic sulfate structure, so that the oxygen release from a positive electrode active material is suppressed, which improves the structural stability of the positive electrode active material.