Nitrile-Coated Lithium Battery Electrode for Thermal Runaway Resistance
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Solution Overview
Problem
Non-aqueous lithium secondary batteries face issues with resistance layer formation and safety due to reactions between the cathode active material and electrolyte, leading to performance degradation and potential thermal runaway, especially at high temperatures and during overcharge.
Innovation Solution
Incorporating an aliphatic nitrile compound, such as succinonitrile, into the electrode to form a strong complex with transition metals or metal oxides, which enhances the electrode's surface protection and prevents the formation of resistance layers, thereby maintaining battery performance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an aliphatic dinitrile compound is used as an additive for electrolyte, then the safety of the battery is improved, but the viscosity of the electrolyte increases, resulting in degradation of battery performance at low temperature
Solution Approach 1:
The patent introduces a coating layer comprising an aliphatic nitrile compound as an intermediary between the electrode and the electrolyte. This coating layer mediates the interaction by providing safety benefits without directly increasing electrolyte viscosity. The coating acts as a mediator that delivers the protective function while avoiding the harmful side effect of increased electrolyte viscosity that would occur if the nitrile compound were added to the electrolyte itself.
Solution Approach 2:
The patent segments the functional components by separating the safety-providing aliphatic nitrile compound from the electrolyte and placing it instead in the electrode coating. This segmentation allows the safety function to be localized in the electrode structure without affecting the bulk electrolyte properties, thereby avoiding the viscosity increase problem while maintaining low-temperature performance.
2Reliability
If the battery is stored at high temperature, then the resistance layer formation is accelerated, but the battery lifetime significantly decreases
Solution Approach 1:
The coating layer comprising the aliphatic nitrile compound provides preliminary protection to the electrode surface before high-temperature storage conditions cause harmful reactions. The coating acts as a preventive barrier that counteracts the tendency of the electrolyte to react with the cathode active material at high temperatures, thereby preventing resistance layer formation and extending battery lifetime.
Solution Approach 2:
The patent converts the potential harm of high-temperature storage into a benefit by using the controlled decomposition or transformation of the aliphatic nitrile compound in the coating layer. The coating may undergo beneficial changes at high temperature that further enhance protection, or the presence of the coating simply prevents the harmful reactions that would otherwise occur, effectively converting the high-temperature stress condition into an opportunity for demonstrating enhanced stability.
3Reliability
If overcharge proceeds, then heat emission occurs causing internal temperature increase, but the battery shows safety problems such as ignition or explosion
Solution Approach 1:
The coating layer comprising the aliphatic nitrile compound provides beforehand cushioning protection during overcharge conditions. The coating absorbs or mitigates the heat generation and chemical reactions that occur during overcharge, acting as a buffer that prevents the temperature increase from reaching critical levels that would cause thermal runaway, ignition, or explosion.
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 aliphatic nitrile compound effectively inhibits exothermic reactions and structural collapse, improving battery safety and performance by maintaining efficient lithium ion intercalation/deintercalation and preventing ignition and explosion, while maintaining battery performance without degrading it at low temperatures.
Implementation Method 1
an aliphatic nitrile compound, preferably a compound represented by the following formula 1, whose surface is coated with the aliphatic nitrile compound or which comprises an electrode active material comprising the aliphatic nitrile compound
Implementation Method 2
Non-aqueous electrolyte-based secondary batteries face issues with resistance layer formation and safety due to reactions between the cathode active material and electrolyte
Implementation Method 3
maintaining efficient lithium ion intercalation/deintercalation
Implementation Method 4
The aliphatic nitrile compound effectively inhibits exothermic reactions and structural collapse, improving battery safety and performance
Data Source
AI summary
Disclosed is an electrode comprising an aliphatic nitrile compound, wherein the aliphatic nitrile compound is coated on a surface of the electrode or is incorporated into the electrode active materials. A lithium secondary battery having the electrode is also disclosed. The lithium secondary battery has excellent safety so as to prevent ignition and explosion generated when the internal temperature of the battery is increased due to the heat emission caused by the reaction of an electrolyte with a cathode and the structural collapse of a cathode occurring upon overcharge. Additionally, it is also possible to prevent ignition and explosion when the battery is exposed to high temperature due to an increase in temperature resulting from heating or local short circuit caused by physical impacts. Further, it is possible to solve the problems of an increase in viscosity and degradation in battery performance at a low temperature occurring when an aliphatic nitrile compound is used as an additive for electrolyte.