Gel Electrolyte Composition for Durable Lithium Metal Batteries
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Solution Overview
Problem
The durability of lithium metal secondary batteries is compromised due to increased cell resistance caused by the use of polymer compounds with gelation functions, which changes the solvation structure of the electrolytic solution when a Π-Π stacking interaction is utilized.
Innovation Solution
Incorporating a gel electrolyte layer with a gelation agent that utilizes Π-Π stacking interaction, featuring a perfluoroalkyl group and a phenylene group, along with an electrolytic solution containing dimethyl carbonate and lithium bis(fluorosulfonyl)imide, to maintain the solvation structure and suppress dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymer compound with gelation function is used in the gel electrolyte layer, then the gel electrolyte structure is formed, but the cell resistance increases and durability deteriorates
Solution Approach 1:
The patent changes the chemical structure parameters of the gelation agent by introducing perfluoroalkyl groups and phenylene groups, which modify the gelation mechanism through Π-Π stacking interactions. This structural parameter change allows the gel electrolyte to maintain lower resistance while improving durability, resolving the contradiction between resistance and durability.
Solution Approach 2:
The patent creates a composite gel electrolyte system combining the perfluoroalkyl-containing gelation agent with specific electrolyte components (dimethyl carbonate and lithium bis(fluorosulfonyl)imide). This composite material approach enables the gel structure to provide mechanical stability without the harmful resistance effects of conventional polymer gelators, simultaneously improving durability and reducing resistance.
2Reliability
If a gelation agent utilizing Π-Π stacking interaction is used, then the gel electrolyte is formed, but the solvation structure of the electrolytic solution changes leading to durability deterioration
Solution Approach 1:
The patent applies local quality modification by introducing perfluoroalkyl groups and phenylene groups at specific positions in the gelation agent molecule. These localized structural features enable Π-Π stacking interactions that form the gel network without disrupting the overall solvation structure of the electrolytic solution, thus maintaining composition stability while achieving gelation.
Solution Approach 2:
The patent carefully controls the parameters of the gelation agent structure, specifically the perfluoroalkyl chain length and phenylene group positioning, to ensure that the gelation process does not alter the solvation structure. By adjusting these molecular parameters, the gel electrolyte forms through Π-Π stacking while the electrolyte's solvation characteristics remain stable, preventing durability deterioration.
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
This configuration enhances the durability of the lithium metal secondary battery without altering the solvation structure, as evidenced by improved capacity retention and suppressed dendrite growth, leading to a more stable battery performance.
Implementation Method 1
a gelation agent utilizing a Π-Π stacking interaction
Implementation Method 2
suppress dendrite growth
Data Source
AI summary
To provide a lithium metal secondary battery including a gel electrolyte layer between a positive electrode and a negative electrode, the positive electrode including a positive electrode current collector and a positive electrode mixture layer containing a lithium composite oxide, the negative electrode including a negative electrode current collector, the gel electrolyte layer including: a gelation agent utilizing a π-π stacking interaction and an electrolytic solution, the gelation agent having a perfluoroalkyl group and a phenylene group.