Non-Aqueous Battery Electrolyte Additive for Cathode Film Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face degradation due to the dissolution of transition metals from the positive electrode, leading to increased resistance and reduced capacity, as well as safety concerns from dendrite growth causing internal short-circuits.
Innovation Solution
A non-aqueous electrolyte solution for lithium secondary batteries is developed, which includes a lithium salt, an organic solvent, and a first additive represented by Formula 1. This additive forms a robust film on the positive electrode, suppressing transition metal dissolution and scavenging decomposition products, thereby enhancing high-temperature storage and cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a lithium-ion battery uses a positive electrode containing transition metal oxide, then energy storage capacity is improved, but transition metal dissolves during charge-discharge cycles leading to increased resistance and capacity degradation
Solution Approach 1:
The patent introduces a specific additive (Formula 1 compound) as an intermediary substance in the electrolyte that mediates between the positive electrode and electrolyte solution. This additive forms a protective interface layer that prevents direct contact and harmful reactions between the transition metal oxide and electrolyte, thereby reducing metal dissolution and resistance increase while maintaining energy storage capacity.
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating a specific additive with defined molecular structure (Formula 1). This parameter change in the electrolyte composition leads to altered interfacial properties, forming a stable protective film that suppresses transition metal dissolution and maintains electrode performance during cycling.
2Quantity of substance
If transition metal dissolves in the electrolyte solution, then the battery capacity degrades, but the dissolved metal is re-deposited on the positive electrode increasing resistance
Solution Approach 1:
The patent converts the harmful dissolution process into a beneficial protective mechanism. The additive causes controlled formation of a stable interface film that prevents harmful metal dissolution while allowing beneficial lithium ion transport. The initial metal dissolution tendency is redirected to form a protective layer rather than free metal ions in the electrolyte.
Solution Approach 2:
The additive acts as an intermediary that intercepts dissolved transition metal ions before they can re-deposit on the positive electrode. This mediator substance binds or sequesters the metal ions in the electrolyte, preventing their re-deposition and the associated resistance increase, while maintaining lithium ion conductivity.
3Reliability
If metal ions electrodeposit on the negative electrode as dendrites, then internal short-circuit occurs, but this reduces battery safety
Solution Approach 1:
The additive serves as an intermediary that interacts with metal ions in the electrolyte, preventing their migration and deposition on the negative electrode. This mediator substance creates a more uniform ion distribution and suppresses dendrite formation, thereby eliminating the safety hazard of internal short-circuits.
Solution Approach 2:
The additive performs preliminary anti-action by preventing metal ion migration to the negative electrode before dendrite formation can occur. The protective effect is established in advance during initial cycles, creating a stable interface that prevents subsequent dendrite growth and potential short-circuits.
4Power
If the electrolyte solution decomposes at high operating potential, then transition metal dissolves, but this increases interfacial resistance and promotes additional decomposition
Solution Approach 1:
The additive performs preliminary action by forming a stable protective film on the positive electrode before high-potential operation begins. This pre-formed interface layer prevents electrolyte decomposition and transition metal dissolution during high-potential charging, maintaining low interfacial resistance and preventing the vicious cycle of decomposition and resistance increase.
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 proposed solution effectively improves the high-temperature storage and cycle performance of lithium secondary batteries by preventing transition metal dissolution and mitigating self-discharge, resulting in enhanced capacity retention and reduced resistance increase during high-temperature conditions.
Implementation Method 1
a compound represented by Formula 1, which is included in a non-aqueous electrolyte solution of the present invention, as a Lewis base-based compound containing a phosphite (P03) group in its structure, may achieve a lithium secondary battery having improved high-temperature storage characteristics and cycle characteristics by suppressing dissolution of transition metal from a positive electrode by forming a robust film on the positive electrode during oxidation
Implementation Method 2
simultaneously scavenging a decomposition product caused by decomposition of anions of a lithium salt in the battery during charge and discharge
Implementation Method 3
a lithium-ion battery is composed of a positive electrode formed of a transition metal oxide containing lithium, a negative electrode capable of storing the lithium, an electrolyte solution that includes an organic solvent containing a lithium salt
Data Source
AI summary
A non-aqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery including the same are disclosed herein. In some embodiments, non-aqueous electrolyte solution includes a lithium salt, an organic solvent, and a compound represented by Formula 1 as a first additive. A lithium secondary battery including the non-aqueous electrolyte has improved flame retardancy.