Pyrrolidine Derivative Electrolyte for Lithium Battery Oxidation
Solution Overview
Problem
Lithium secondary batteries face challenges in preventing oxidation and dissolution of electrolytes on positive electrode surfaces during high-voltage charging, which affects their lifespan and high-rate characteristics.
Innovation Solution
An electrolyte composition including a lithium salt, a non-aqueous organic solvent, and a pyrrolidine derivative that forms a protective film on the positive electrode surface, allowing lithium ions to pass through while preventing electrolyte oxidation, thereby enhancing the battery's lifespan and high-rate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If over-charge protectors are used to form films on positive electrode surfaces, then electrolyte oxidation is prevented, but thick films are formed that block lithium ion transfer and prevent current flow
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte additive, specifically using pyrrolidine derivatives with specific molecular structures (Formula 1) instead of conventional over-charge protectors. This parameter change enables the formation of thin protective films that maintain lithium ion conductivity while preventing electrolyte oxidation.
Solution Approach 2:
The patent applies local quality by creating a specifically structured protective film on the positive electrode surface through pyrrolidine derivative additives. The film has localized protective properties (preventing oxidation) while maintaining local conductivity (allowing lithium ion passage), achieving both protection and functionality in the same structure.
2Duration of action of stationary object
If film thickness is reduced to improve lifespan characteristics, then over-charging prevention is maintained, but lithium ions cannot easily pass through the films
Solution Approach 1:
The patent uses composite material principles by combining pyrrolidine derivatives with specific functional groups (X and R1-R4 in Formula 1) to create a composite protective film structure. This composite structure achieves both thin film morphology (for ion conductivity) and protective functionality (for lifespan extension) simultaneously.
Solution Approach 2:
The patent changes the chemical structure parameters of the additive molecules (specifically the pyrrolidine ring structure with various substituent groups) to control film formation characteristics. This enables the formation of ultra-thin films that maintain both protective function and high ion conductivity.
3Use of energy by moving object
If high voltage positive electrode materials are used to increase energy density, then battery energy density is improved, but electrolyte oxidation on positive electrode surfaces increases
Solution Approach 1:
The patent introduces pyrrolidine derivative additives as intermediary substances that mediate between the high voltage positive electrode materials and the electrolyte. These additives form protective interface films that prevent direct contact and oxidation reactions, enabling high voltage operation without electrolyte degradation.
Solution Approach 2:
The patent applies preliminary anti-action by having the pyrrolidine derivatives react first to form protective films on the positive electrode surface before electrolyte oxidation can occur. This preliminary protective action prevents subsequent harmful oxidation reactions during high voltage charging.
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 effectively forms a thin film on the positive electrode surface, preventing electrolyte oxidation and maintaining high capacity retention and charge efficiency, thus improving the lithium secondary battery's lifespan and high-rate characteristics.
Implementation Method 1
the electrolytes are more prone to oxidation on positive electrode surfaces
Implementation Method 2
lithium ions may not easily pass through the films
Data Source
AI summary
An electrolyte for a lithium secondary battery including a lithium salt, a non-aqueous organic solvent, and a pyrrolidine derivative represented by Formula 1,wherein, in Formula 1, X is hydrogen, a formyl group or a salt thereof, a carboxyl group or a salt thereof, a C1-C20 alkyl group, a C1-C20 hydroxyalkyl group, a C1-C20 aminoalkyl group, a C1-C20 thioalkyl group, or a C1-C20 cyanoalkyl group, and R1 to R4 are each independently hydrogen, deuterium, a halogen atom, a hydroxyl group, a thio group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine, a hydrazone, a formyl group or a salt thereof, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid or a salt thereof, a C1-C20 hydroxyalkyl group, a C2-C20 heteroaryl group, or a C6-C20 aryl group.