Dinitrile Electrolyte Additive for High-Voltage Battery Safety
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Solution Overview
Problem
Dual intercalation non-aqueous electrolyte storage elements face issues with gas generation during charging and discharging cycles due to electrolyte decomposition at the electrode-electrolyte interface, which affects safety and cycle properties, especially at high voltages, and existing solutions do not adequately address these concerns without compromising energy density or input-output properties.
Innovation Solution
A non-aqueous electrolyte storage element design incorporating a positive electrode with a carbon-based active material capable of anion insertion, a negative electrode with lithium-ion accumulating capabilities, and a non-aqueous electrolyte containing a dinitrile compound in limited concentrations (33% by mass or less) to suppress gas generation and enhance high-voltage resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual intercalation non-aqueous electrolyte storage element is used to achieve high energy density and stable operation, then energy density and operational stability are improved, but gas generation increases during charging and discharging cycles
Solution Approach 1:
A film-forming additive is introduced as an intermediary substance between the electrolyte and electrode. This additive forms a protective interface film that mediates the interaction between electrolyte and electrode, preventing direct harmful reactions while allowing ion transport. The film acts as a buffer layer that suppresses gas generation without compromising the dual intercalation mechanism's energy density benefits.
Solution Approach 2:
The composition parameters of the electrolyte are modified by adding specific film-forming compounds. By changing the chemical composition and concentration ratios of electrolyte components, the properties of the interface film are optimized to reduce gas generation while maintaining stable operation. The additive concentration and molecular structure are tuned to achieve the desired balance between protection and performance.
2Reliability
If the electrolyte composition is modified to suppress decomposition at high voltage, then high-voltage resistance is improved, but energy density may be compromised
Solution Approach 1:
Instead of completely reforming the electrolyte composition, a small partial amount of film-forming additive is added to the existing high-performance electrolyte system. This partial modification is sufficient to form the necessary protective film at the interface, providing high-voltage resistance without significantly altering the bulk electrolyte properties that enable high energy density. The minimal additive concentration ensures energy density is preserved.
3Productivity
If electrode film thickness is reduced to improve input-output properties, then charging and discharging speed is improved, but structural stability and cycle life may deteriorate
Solution Approach 1:
A protective film is formed beforehand on the thin electrode structure before it undergoes repeated charging and discharging cycles. This pre-formed film acts as a cushioning layer that protects the thin electrode from mechanical stress and chemical degradation during cycling. The film absorbs and distributes stress, preventing structural failure that would otherwise occur in thin electrodes, thereby extending cycle life while maintaining high input-output properties.
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 solution effectively reduces gas generation, maintains energy density, and improves input-output properties without deteriorating battery performance, ensuring high safety and long-term cycle stability even at high voltages.
Implementation Method 1
decomposition of an electrolyte occurs at an interface between an electrode and the electrolyte
Implementation Method 2
a positive electrode including a positive-electrode active material capable of inserting and eliminating anions
Implementation Method 3
a negative electrode including a negative-electrode active material
Data Source
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AI summary
Provided is a non-aqueous electrolyte electricity-storage element (10), which includes: a positive electrode (11) including a positive-electrode active material (21) capable of inserting and eliminating anions; a negative electrode (12) including a negative-electrode active material (25); a non-aqueous electrolyte (26); and a separator (13) that is disposed between the positive electrode (11) and the negative electrode (12) and retains the non-aqueous electrolyte (26), wherein the non-aqueous electrolyte (26) includes a dinitrile compound, and an amount of the dinitrile compound is 33% by mass or less relative to the non-aqueous electrolyte (26).