Lithium Battery Electrolyte Additive for High-Voltage Interface Stability
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Solution Overview
Problem
Rechargeable lithium batteries face safety issues and decreased lifecycle due to side reactions between electrodes and electrolyte solution under high-voltage and high-temperature conditions, leading to increased resistance and gas generation.
Innovation Solution
Incorporation of a specific additive in the electrolyte solution, represented by Chemical Formula 1, forms a stable film at the electrode interface, reducing side reactions and suppressing resistance increase, thereby improving safety and lifecycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high voltage (4.45 V or more) is used to increase energy density, then battery capacity and energy density are improved, but side reactions between electrodes and electrolyte solution accelerate, causing safety issues and decreased lifecycle
Solution Approach 1:
A film-forming additive is introduced as an intermediary substance between the electrode and electrolyte solution. This additive forms a protective interface film that mediates the interaction, preventing direct harmful contact while allowing ionic transport, thus resolving the contradiction between high voltage operation and battery lifecycle
Solution Approach 2:
The chemical composition and properties of the electrolyte solution are modified by adding specific film-forming additives. This changes the interface characteristics between electrode and electrolyte, creating a stable protective layer that enables high voltage operation without sacrificing battery lifecycle
2Object-affected harmful factors
If surface treatment is applied to protect electrodes, then side reactions are reduced, but the positive electrode treatment is insufficient under high voltage and negative electrode treatment deteriorates capacity
Solution Approach 1:
The film-forming additive performs multiple functions simultaneously: it forms protective films on both positive and negative electrodes, provides ion transport channels, and maintains electrode performance. This multi-functional approach resolves the contradiction between reducing side reactions and maintaining electrode performance
Solution Approach 2:
Instead of physical surface treatment, the chemical composition of the electrolyte interface is changed through additive incorporation. This creates a functional protective layer that reduces side reactions while preserving, and even enhancing, electrode performance through improved interface stability
3Speed
If rapid charging is performed to improve charging speed, then charging time is reduced, but resistance increases and battery safety deteriorates
Solution Approach 1:
The film-forming additive creates an intermediary protective layer that enables rapid charging by providing stable ion transport pathways. This mediator prevents direct harmful interactions during high-rate charging, resolving the contradiction between charging speed and battery safety
Solution Approach 2:
The protective film is formed in advance during initial charging cycles, creating a pre-established safe interface that enables subsequent rapid charging operations. This preliminary action resolves the contradiction by preparing the interface before high-speed charging begins
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 enhances rapid charging characteristics, reduces internal resistance, and improves battery safety and lifecycle under high-voltage conditions, maintaining capacity and reliability.
Implementation Method 1
Incorporation of a specific additive in the electrolyte solution, represented by Chemical Formula 1, forms a stable film at the electrode interface
Implementation Method 2
forms a stable film at the electrode interface, reducing side reactions
Implementation Method 3
an electrolyte solution including an organic solvent and a lithium salt is most commonly used because the lithium salt can exhibit high ionic conductivity
Implementation Method 4
reduces or suppresses the increase in resistance within the battery
Data Source
AI summary
Provided are a rechargeable lithium battery including a positive electrode, a negative electrode, a separator, and an electrolyte solution, wherein the positive electrode includes a positive electrode active material including a layered lithium nickel-manganese-based composite oxide, the electrolyte solution includes a non-aqueous organic solvent, a lithium salt, and an additive. The rechargeable lithium battery has improved rapid charging characteristics and reduced or suppressed increase in resistance within the battery, ensuring battery safety and high temperature reliability under high-voltage operating conditions, and improving capacity characteristics and lifecycle characteristics.