Composite Electrolyte With Fibrous Polymer for Low-Resistance Solid Batteries
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Solution Overview
Problem
Current all-solid secondary batteries using solid electrolytes face challenges with ionic conductivity, reaction resistance, and interface resistance, leading to deteriorated discharge performance and cycle life due to electrode expansion/contraction and decreased bonding between the electrode and solid electrolyte, making them unsuitable for practical use.
Innovation Solution
A composite electrolyte comprising inorganic solid particles, an ionic liquid, and a fibrous polymer with an average fiber diameter of 1 to 100 nm, where the fibrous polymer content is between 0.5 to 10% by weight, enhances ionic conductivity and adhesiveness, preventing electrode peeling and improving thermal stability and cycle life performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If solid electrolytes are used, then non-flammability is improved, but discharge rate performance deteriorates due to increased resistance
Solution Approach 1:
The composite electrolyte combines non-flammable inorganic solid particles with highly conductive ionic liquids, maintaining non-flammability while achieving sufficient ionic conductivity for high discharge rate performance.
Solution Approach 2:
The fibrous polymer with specific diameter (1 to 100 nm) is distributed throughout the electrolyte to locally enhance ion transport pathways, improving discharge rate performance while maintaining overall safety.
2Temperature
If solid electrolytes are used, then thermal stability is improved, but cycle life performance deteriorates due to electrode expansion/contraction and decreased bonding
Solution Approach 1:
The composite electrolyte maintains the thermal stability of inorganic solids while the ionic liquid and fibrous polymer components provide flexibility to accommodate electrode expansion and contraction, preventing bonding degradation over cycles.
Solution Approach 2:
The ionic liquid component provides dynamic adaptability to the electrolyte system, allowing it to flexibly respond to electrode volume changes during charge-discharge cycles, thereby maintaining stable bonding and improving cycle life.
3Reliability
If solid electrolytes are used, then safety is improved, but low-temperature performance deteriorates
Solution Approach 1:
The composite electrolyte combines the safety of inorganic solids with the low-temperature fluidity of ionic liquids, maintaining safety performance while achieving acceptable low-temperature ionic conductivity.
Solution Approach 2:
By selecting ionic liquids with appropriate viscosity characteristics and controlling the fibrous polymer content, the electrolyte maintains sufficient ionic mobility at low temperatures while retaining the safety advantages of solid components.
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 composite electrolyte achieves high ionic conductivity, thermal stability, and improved adhesiveness to electrodes, reducing interface resistance and enhancing charge-and-discharge cycle life and high-temperature storage performance of secondary batteries.
Implementation Method 1
research and development to enhance the ionic conductivity of oxide solid electrolytes and sulfide solid electrolytes are in progress
Implementation Method 2
the interface resistance between the electrode and the solid electrolyte increases due to the decrease in the bonding between the electrode and the solid electrolyte
Data Source
AI summary
According to one embodiment, a composite electrolyte includes inorganic solid particles, an ionic liquid and 0.5 to 10% by weight of a fibrous polymer. The ionic liquid includes cations and anions. The fibrous polymer has an average fiber diameter of 1 to 100 nm.