Non-aqueous Battery Electrolyte Additives for High-Voltage Stability
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Solution Overview
Problem
Lithium-ion secondary batteries with high voltage face challenges in maintaining charging/discharging cycle properties and safety due to expansion issues during storage at high temperatures, especially when charged to voltages above 4.3V, as existing technologies do not adequately address the decomposition reactions of non-aqueous electrolytic solutions with high voltage positive electrodes.
Innovation Solution
Incorporating a non-aqueous electrolytic solution with additives such as sulfonic acid anhydrides, sulfonate ester derivatives, cyclic sulfate derivatives, cyclic sulfonate ester derivatives, and vinylene carbonate or its derivatives, along with a positive electrode containing layered or spinel lithium-containing compound oxides, to suppress decomposition reactions and enhance stability at high voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If charging voltage is increased to improve capacity and energy density, then battery capacity and energy density are improved, but safety and charging/discharging cycle properties deteriorate
Solution Approach 1:
A protective film is introduced as an intermediary layer between the positive electrode active material and the non-aqueous electrolytic solution. This film, formed by additives in the electrolyte, mediates the interaction by preventing direct harmful reactions while allowing lithium ion transport, thus enabling high voltage charging without deteriorating cycle properties
Solution Approach 2:
The chemical composition and properties of the non-aqueous electrolytic solution are changed by adding specific additives (cyclic carboxylic acid esters, chain carboxylic acid esters, and cyclic carbonate esters in specific ratios). This parameter change modifies the electrolyte's reactivity and film-forming characteristics, allowing stable operation at charging voltages of 4.3V or higher
2Quantity of substance
If charging voltage is increased to improve capacity and energy density, then battery capacity and energy density are improved, but safety deteriorates
Solution Approach 1:
The protective film acts as a safety intermediary that prevents direct contact and harmful reactions between the high-voltage positive electrode and the electrolyte, thereby maintaining safety even when charged to 4.3V or higher
Solution Approach 2:
The potential harmful decomposition reactions between the high-voltage positive electrode and electrolyte are converted into a beneficial protective film formation process. The initial controlled reaction creates a stable interface that prevents subsequent harmful reactions, turning a potential safety hazard into a protective mechanism
3Temperature
If battery is stored at high temperature, then thermal energy is present, but expansion occurs due to gas generation from decomposition reactions
Solution Approach 1:
The protective film serves as a thermal intermediary barrier that reduces direct thermal interaction between the positive electrode and electrolyte during high-temperature storage, preventing decomposition reactions that would generate gas and cause expansion
Solution Approach 2:
The electrolyte composition is modified with specific additives that change the thermal stability parameters of the battery system. These additives lower the decomposition temperature threshold and prevent harmful reactions even when stored at elevated temperatures, thereby preventing gas generation and expansion
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 improves the charging/discharging cycle properties and safety of lithium-ion batteries at high temperatures by preventing solvent decomposition and gas generation, maintaining battery integrity and capacity even when charged to higher voltages.
Implementation Method 1
a dense protective film derived from the additives is formed on a surface of a negative electrode
Implementation Method 2
The film continuously prevents the negative electrode from being reacted with the organic solvent in the non-aqueous electrolytic solution
Implementation Method 3
A lithium-ion secondary battery has been used... since the battery has advantageous properties such as a high voltage (operating voltage 4.2V)
Data Source
AI summary
A non-aqueous secondary battery contains a positive electrode, a negative electrode, a separator and a non-aqueous electrolytic solution. The positive electrode contains a layered structure lithium-containing compound oxide, or a spinel lithium-containing compound oxide containing manganese as an active material. The non-aqueous electrolytic solution contains at least one additive selected from a sulfonic acid anhydride, a sulfonate ester derivative, a cyclic sulfate derivative and a cyclic sulfonate ester derivative, and a vinylene carbonate or a derivative of the vinylene carbonate.