Ionic Liquid Quasi-Solid Electrolyte Porous Network
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Solution Overview
Problem
Lithium metal batteries face challenges such as lithium dendrite formation and low coulombic efficiency during charge-discharge cycles, which hinder commercialization, and existing solid electrolytes with inactive materials like SiO2 or TiO2 restrict ionic conductivity.
Innovation Solution
An ionic liquid-based quasi-solid-state electrolyte with a porous network structure is developed through a condensation reaction involving a lithium salt, ionic liquid, silane coupling agent, and catalyst, promoting lithium ion dissociation and migration, and inhibiting dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solidified ionic liquid electrolyte is used to prevent leakage and improve safety, then thermal stability and leakage resistance are improved, but ionic conductivity is reduced due to hindrance of lithium ion migration in the solidified structure
Solution Approach 1:
The patent employs a porous polymer matrix structure that maintains the solidified state for leakage prevention while creating void spaces that facilitate ionic liquid infiltration and lithium ion migration. The porous structure resolves the contradiction by providing both mechanical stability (preventing leakage) and ionic conduction pathways (maintaining conductivity).
Solution Approach 2:
The patent creates a composite electrolyte system combining solid polymer matrix with liquid ionic liquid filler. This composite structure leverages the advantages of both phases: the solid polymer provides structural integrity and leakage resistance, while the liquid ionic liquid maintains high ionic conductivity. The synergistic combination resolves the fundamental contradiction between solidification and conductivity preservation.
2Stability of the object's composition
If electrochemically inactive materials like SiO2 or TiO2 are used as solidified electrolyte matrix, then structural stability is improved, but ionic conduction function is lost due to lack of coordination with lithium ions
Solution Approach 1:
The patent changes the chemical parameters of the matrix material by introducing functional groups (such as ether groups, carbonyl groups, or ester groups) that can coordinate with lithium ions. This parameter modification transforms the matrix from electrochemically inactive to active, enabling ionic conduction while preserving structural stability. The functional groups create coordination sites for lithium ion migration without compromising the overall matrix integrity.
3Quantity of substance
If lithium metal is used as negative electrode to achieve high theoretical capacity, then energy density is improved, but lithium dendrite formation occurs during charge-discharge cycles
Solution Approach 1:
The patent introduces a quasi-solid-state electrolyte as an intermediary layer between the lithium metal electrode and the external environment. This intermediary electrolyte with its unique properties (appropriate viscosity, ionic conductivity, and mechanical strength) mediates the interaction between lithium ions and the electrode, promoting uniform deposition and preventing dendrite formation while allowing high capacity utilization.
Solution Approach 2:
The patent modifies the physical parameters of the electrolyte system by using a quasi-solid-state formulation with optimized viscosity and mechanical properties. These parameter changes create a more favorable environment for uniform lithium ion flux distribution during charging, reducing concentration gradients that lead to dendrite formation, while maintaining high ionic conductivity to support 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
The electrolyte achieves high ionic conductivity, stabilizes lithium metal stripping/deposition, inhibits dendrite growth, and exhibits long-term cycle stability and high-temperature resistance, making it suitable for large-scale production.
Implementation Method 1
An ionic liquid-based quasi-solid-state electrolyte with a porous network structure is developed through a condensation reaction involving a lithium salt, ionic liquid, silane coupling agent, and catalyst, promoting lithium ion dissociation and migration
Implementation Method 2
Such material has a porous network structure, which is primarily responsible for mechanical strength, and meanwhile provides a large adsorption space for the loaded ionic liquid
Data Source
AI summary
The present disclosure relates to an ionic liquid-based quasi-solid-state electrolyte in a lithium battery and a preparation method thereof. The quasi-solid-state electrolyte is of a porous network structure, which is obtained by a condensation reaction of a lithium salt, ionic liquid, a silane coupling agent and a catalyst, and has a high ionic conductivity. The quasi-solid-state electrolyte can stabilize a stripping/deposition process of lithium metal and inhibit growth of lithium dendrites, and shows a low overpotential and long-term cycle stability in a constant current polarization process. The interface impedance of a lithium metal sheet and the quasi-solid-state electrolyte is low, and is hardly increased with the age of the battery.