Rechargeable Battery Electrolyte Additives for High-Voltage Film Stability
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Solution Overview
Problem
Rechargeable lithium batteries face challenges in achieving stability and extended lifetime at high voltages due to electrolyte decomposition and transition metal dissolution during charge-discharge cycles.
Innovation Solution
Incorporation of a non-aqueous organic solvent, lithium salt, a first additive (lithium difluoro(oxalato)borate) and a second additive (represented by Chemical Formula 2) in the electrolyte, which forms protective films on electrodes to suppress decomposition and stabilize lithium salts, enhancing the solid electrolyte interface layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte composition is used, then basic battery operation is achieved, but electrolyte decomposition and transition metal dissolution occur at high voltages
Solution Approach 1:
The patent introduces a mediator substance (specifically, a sulfone compound with formula (1)) that acts as an intermediary between the electrolyte and electrode. This mediator forms a protective interface layer that prevents direct harmful interactions between the electrolyte and electrode materials at high voltages, thereby suppressing electrolyte decomposition and transition metal dissolution while maintaining basic battery operation.
Solution Approach 2:
The patent employs a composite electrolyte system combining multiple components: conventional electrolyte solvents (cyclic and chain carbonates), lithium salt, and the specialized sulfone compound additive. This composite formulation creates synergistic effects where the sulfone compound enhances the stability of the base electrolyte system under high voltage conditions, preventing decomposition without sacrificing operational functionality.
2Use of energy by moving object
If high voltage operation is pursued, then energy density is improved, but lifetime characteristics deteriorate due to decomposition reactions
Solution Approach 1:
The sulfone compound performs preliminary protective action by preferentially reacting with electrode surfaces and high voltage stress during initial cycles to form a stable protective film. This preliminary action creates a shield that prevents subsequent decomposition reactions during normal high voltage operation, thereby extending battery lifetime while maintaining high energy density.
Solution Approach 2:
The patent converts the potentially harmful high voltage stress that causes decomposition into a beneficial effect. The sulfone compound utilizes the high voltage conditions to form a stabilized protective layer on the electrode, transforming the harsh high voltage environment from a source of degradation into a condition that enhances long-term stability and extends battery life.
3Reliability
If electrolyte additives are increased to suppress decomposition, then stability improves, but gas generation increases
Solution Approach 1:
The patent optimizes the concentration parameter of the sulfone compound additive within a specific range (0.1-5 wt%). This precise parameter control ensures sufficient stability enhancement through protective film formation while minimizing gas generation side reactions. The optimized concentration balances the competing effects of decomposition suppression and gas evolution.
Solution Approach 2:
The sulfone compound concentrates its protective effect locally at the electrode-electrolyte interface where decomposition occurs most severely. By targeting the interface region specifically through preferential adsorption and film formation, the additive provides localized stability enhancement without uniformly affecting the bulk electrolyte, thereby minimizing overall gas generation while maintaining electrolyte stability.
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 electrolyte composition improves the battery's high-temperature storage performance, reduces gas generation, and maintains capacity by preventing transition metal dissolution, resulting in improved lifetime and output characteristics.
Implementation Method 1
forms protective films on electrodes to suppress decomposition and stabilize lithium salts, enhancing the solid electrolyte interface layer
Implementation Method 2
the positive and negative electrodes include an active material in which intercalation and deintercalation (e.g. of lithium ions) are possible
Implementation Method 3
the rechargeable lithium battery generates electrical energy caused by oxidation and reduction reactions if (e.g., when) lithium ions are intercalated and/or deintercalated
Data Source
AI summary
An electrolyte including a non-aqueous organic solvent, a lithium salt, a first additive, and a second additive and rechargeable lithium batteries including the electrolyte are provided. The electrolyte first additive is represented by Chemical Formula 1 and the second additive is represented by Chemical Formula 2.