Hybrid Solid Electrolyte for High Ionic Conductivity
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Solution Overview
Problem
State-of-the-art solid electrolyte materials for lithium batteries face challenges in achieving high room temperature ionic conductivity and low interfacial resistance with electrodes, particularly due to the rigidity of inorganic materials and poor conductivity of polymer electrolytes, which are exacerbated by the use of liquid plasticizers that compromise mechanical properties and stability.
Innovation Solution
A hybrid solid electrolyte comprising a PEO-based copolymer with POSS units, solvate ionic liquids (SILs), and a monovalent cation salt, where the SILs are incorporated within the polymer matrix to preserve their unique solvate structure, achieving high ionic conductivity and voltage stability by forming continuous Li+ channels and strong adhesion with electrodes, and further enhanced by ionically conducting ceramic particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic electrolytes are used, then ionic conductivity is improved, but interfacial resistance with electrodes increases
Solution Approach 1:
The patent employs a composite structure combining inorganic electrolyte particles (providing high ionic conductivity) dispersed within a polymer electrolyte matrix (providing flexibility and low interfacial resistance). This composite approach allows the system to simultaneously achieve the high ionic conductivity of inorganic materials and the good electrode interface properties of polymer materials, resolving the contradiction between these two properties.
2Reliability
If liquid plasticizers are added to polymer electrolytes, then ionic conductivity is improved, but mechanical properties and stability deteriorate
Solution Approach 1:
The patent changes the physical state parameter of the plasticizer from liquid to solid by using solid ionic liquids. This parameter change allows the material to maintain the plasticizing effect (improving ionic conductivity) while avoiding the mechanical property deterioration associated with liquid plasticizers. The solid ionic liquid particles disperse within the polymer matrix, providing conductive pathways without compromising structural integrity.
3Strength
If high molecular weight PEO is used, then mechanical strength is improved, but ionic conductivity at room temperature decreases
Solution Approach 1:
The patent applies local quality by creating conductive domains within the polymer matrix. Solid ionic liquid particles are dispersed throughout the PEO matrix, creating localized high-conductivity regions. These conductive domains provide efficient ion transport pathways while the bulk polymer matrix maintains its mechanical strength. The local concentration of ionic liquid particles in specific regions allows high ionic conductivity without requiring the entire polymer structure to be modified.
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 hybrid solid electrolyte exhibits high room temperature ionic conductivity (10−4 S/cm), low interfacial resistance, and electrochemical stability up to 5.2 volts, enabling high energy density and long cycle life, while maintaining mechanical robustness and safety.
Implementation Method 1
the ligand molecule strongly coordinates with the cations and/or anions of the salts, affording high anodic stability
Implementation Method 2
exhibits high room temperature ionic conductivity (10−4 S/cm)... forming continuous Li+ channels
Data Source
AI summary
A polymer hybrid solid electrolyte that possesses high room temperature ionic conductivity, very low interfacial resistance with the electrodes and electrochemical stability window up to 5.2 volts. The polymer-ceramic hybrid solid electrolyte includes: a PEO based copolymer electrolyte; a solvate ionic liquid (SIL); and a salt of a monovalent cation. The inclusion of an ionically conductive additive, such as a ceramic fine powder, can further improve ionic conductivity as well as mechanical properties.