High-Nickel Li-Ion Electrolyte Stabilization Against Gas Side Reactions
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Solution Overview
Problem
Undesirable side reactions in lithium-ion batteries lead to the production of hydrogen, hydrocarbons, and carbon monoxide gases, which can cause thermal runaway events due to increased oxygen production.
Innovation Solution
Incorporating an oxidant in the liquid electrolyte that binds with unsaturated alkenes formed at the anode to form modified oxidants, preventing them from interacting with the nickel cathode and reducing oxygen gas formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If liquid electrolyte is used in lithium-ion battery, then ionic conductivity and battery performance are improved, but undesirable side reactions occur between electrolyte derivatives and nickel cathode producing gases that lead to thermal runaway
Solution Approach 1:
A fluorinated alkene compound is introduced as an intermediary substance in the electrolyte that preferentially reacts with the nickel cathode to form a protective interface layer. This intermediary prevents direct contact between the nickel cathode and other electrolyte components, thereby eliminating harmful side reactions while preserving ionic conductivity.
Solution Approach 2:
The chemical composition of the electrolyte is modified by incorporating fluorinated alkene compounds with specific molecular structures (CF3CF2CH=CH2 or CF3CF2C(CH3)=CH2). These parameter changes in electrolyte composition alter the reaction characteristics at the cathode interface, preventing gas-producing side reactions while maintaining battery performance.
2Quantity of substance
If nickel content in cathode is increased to improve capacity, then battery capacity increases, but side reactions with electrolyte derivatives increase leading to more oxygen production and thermal runaway risk
Solution Approach 1:
The fluorinated alkene compound serves as a mediator that forms a stable protective layer on the high-nickel cathode surface. This intermediary layer prevents oxygen release from the cathode during cycling, allowing high nickel content (and thus high capacity) without the harmful side effects of oxygen production and thermal runaway.
Solution Approach 2:
The potential harm of high-nickel cathodes producing oxygen and undergoing side reactions is converted into a benefit by using fluorinated alkene compounds that preferentially react with nickel to form stable, protective interfaces. This converts the reactive nickel surface from a source of harm into a stabilized structure that enables high capacity operation.
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
Reduces the occurrence of thermal runaway events by minimizing the interaction between alkenes and nickel, thereby stabilizing the lithium-ion battery.
Implementation Method 1
an oxidant that is soluble in the liquid electrolyte and binds with an alkene having between 2 and 4 carbon atoms
Implementation Method 2
a liquid electrolyte including one or both of ethylene carbonate and ethyl methyl carbonate
Data Source
AI summary
A lithium-ion battery includes an anode including graphite and a cathode nickel in a mole percent of about 60 percent or more, based on the total composition of the cathode. The lithium-ion battery includes liquid electrolyte including one or both of ethyl methyl carbonate and ethylene carbonate and an oxidant that is soluble in the liquid electrolyte and binds with an alkene having between 2 and 4 carbon atoms.