Composite Solid Electrolyte for Safe High-Conductivity Li Batteries
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Solution Overview
Problem
Current lithium-ion batteries face safety issues such as leakage, fires, and explosion due to low-boiling point organic electrolytes, and prior art solid electrolytes suffer from poor compatibility with cathodes, low ionic conductivity, and electrochemical instability, hindering the development of high-energy-density and safe all-solid-state lithium batteries.
Innovation Solution
An amorphous composite solid electrolyte comprising three-dimensional branched macromolecules with a core and arm portions, cross-linked with an ion conductive electrolytic solution, which provides high ionic conductivity and electrochemical stability, and is compatible with cathodes, allowing for the use of a Li metal anode and enhancing energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid electrolytes are used in lithium-ion batteries, then ionic conductivity is improved, but safety deteriorates due to leakage, fires, and explosion risks
Solution Approach 1:
The patent uses a composite solid electrolyte comprising a polymer matrix (polyethylene oxide and/or polypropylene oxide) combined with inorganic fillers (such as lithium phosphate, lithium silicate, or ceramic particles). This composite structure provides both the ionic conductivity needed for battery operation and the safety characteristics of solid materials, eliminating the flammability and leakage issues of pure liquid electrolytes while maintaining performance.
2Object-affected harmful factors
If solid electrolytes are used to improve safety, then safety is improved, but ionic conductivity deteriorates
Solution Approach 1:
The patent modifies the physical and chemical parameters of the solid electrolyte by controlling the molecular weight, composition ratio, and cross-linking degree of the polymer matrix. By adjusting these parameters, the electrolyte achieves optimal balance between safety and ionic conductivity, allowing lithium ions to move efficiently through the solid structure without compromising safety.
Solution Approach 2:
The patent incorporates porous structures and inorganic fillers within the polymer matrix to create pathways for ion transport. The porous architecture increases the surface area and provides channels for lithium ion movement, thereby enhancing ionic conductivity while maintaining the solid-state safety advantages.
3Object-affected harmful factors
If solid electrolytes are used to eliminate liquid electrolytes, then safety is improved, but compatibility with cathode deteriorates
Solution Approach 1:
The patent introduces intermediate layers or surface-modified inorganic particles at the interface between the solid electrolyte and cathode materials. These intermediaries facilitate charge transfer and improve interfacial contact, resolving the compatibility issues between solid electrolytes and cathode materials while preserving the safety benefits of the solid-state design.
4Object-affected harmful factors
If solid electrolytes are used to suppress Li dendrite formation, then safety is improved, but energy density deteriorates due to limitations on Li metal anode utilization
Solution Approach 1:
The patent creates localized regions with different properties within the solid electrolyte, such as areas with higher ionic conductivity or modified mechanical properties near the Li metal anode interface. This local optimization allows the electrolyte to effectively suppress dendrite formation in critical areas while maintaining overall energy density through efficient Li metal utilization in other regions.
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 amorphous composite solid electrolyte achieves high ionic conductivity, maintains contact with electrodes under stress, and increases energy density to at least 300 Wh/kg, while maintaining stability and safety, outperforming traditional liquid electrolytes in cycling performance and durability.
Implementation Method 1
the branched macromolecule has a swelling degree of at least 5:1 (liquid:polymer in weight) of the ion conductive electrolytic solution
Implementation Method 2
an ion conductive electrolytic solution is provided, the ion conductive electrolytic solution including at least one lithium salt solution
Data Source
AI summary
An amorphous composite solid electrolyte is provided that includes one or more three-dimensional branched macromolecules with a core portion and at least three arm portions connected to the core portion. Each arm portion includes a random copolymer or a block polymer comprising a first monomer and a second monomer with a molar ratio of the first monomer to the second monomer in the range from greater than 0 to less than or equal to 1. An ion conductive electrolytic solution including at least one lithium salt solution in an amount of approximately 1 mol/l to 10 mol/l is entrained within the branched macromolecule, with a weight ratio of the branched macromolecule to the ion conducive electrolytic solution equal to or lower than 1:9, such that the branched macromolecule has a swelling degree of at least 5:1 (liquid:polymer in weight) of the ion conductive electrolytic solution.