Brush Block Copolymer Electrolytes for Solid-State Batteries
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Solution Overview
Problem
Current block copolymers for solid electrolytes face challenges in achieving ionic conductivities comparable to conventional organic solvent-based liquid electrolytes, particularly due to complex crystallization behavior in PEO-containing systems, which limits their mechanical and electrical properties.
Innovation Solution
Development of brush block copolymers with triblock and pentablock architectures, featuring ionophobic and ionophilic polymer side chains, which form physically cross-linked networks when mixed with electrochemical additives like lithium salts or ionic liquids, suppressing crystallization and enhancing ionic conductivity and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PEO-containing block copolymers are used to achieve ionic conductivity, then ionic conductivity is improved, but crystallization behavior occurs which worsens mechanical properties
Solution Approach 1:
The patent divides the polymer structure into distinct segments: a crystalline block (providing mechanical strength) and an amorphous block containing PEO (providing ionic conductivity). This segmentation allows each block to perform its specialized function without the negative effects of the other, resolving the contradiction between conductivity and mechanical properties
Solution Approach 2:
Different regions of the block copolymer are designed with different properties: the crystalline block provides structural integrity and mechanical strength, while the amorphous PEO block provides ion transport pathways. This local differentiation of properties allows simultaneous achievement of high conductivity and mechanical strength
2Strength
If conventional block copolymer structures are used, then mechanical strength is achieved, but ionic conductivity remains insufficient
Solution Approach 1:
The patent creates a composite block copolymer structure combining crystalline and amorphous blocks, where each block contributes different properties. The crystalline block provides mechanical strength while the amorphous PEO block provides ionic conductivity, achieving a composite effect that overcomes the limitations of conventional homogeneous structures
3Reliability
If PEO is used in block copolymers to enhance conductivity, then ionic conductivity increases, but complex crystallization behavior develops
Solution Approach 1:
By segregating PEO into a distinct amorphous block separate from the crystalline block, the patent eliminates the complex crystallization behavior that occurs in PEO-containing block copolymers. The PEO remains amorphous and dedicated to ion transport, while the crystalline block handles structural requirements, simplifying the overall system behavior
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 brush block copolymer electrolytes exhibit high ionic conductivity and mechanical strength, with normalized conductivities exceeding those of linear block copolymer blends, and demonstrate thermoreversibility, allowing for tunable mechanical properties across temperature ranges.
Implementation Method 1
the copolymers provided herein are capable of physical cross-linking to generate polymer networks with useful chemical properties
Implementation Method 2
suppressing crystallization and enhancing ionic conductivity and mechanical strength
Implementation Method 3
Polymer systems compatible with efficient complexation of lithium ions, for example, allow for loading of more salt and greater availability of Li ions
Implementation Method 4
the copolymers provided herein are capable of physical cross-linking to generate polymer networks with useful chemical properties, for example, the capability of solvating ions
Implementation Method 5
Block copolymers are an attractive material for polymer electrolytes due to their ability to self-assemble to form supramolecular structures characterized by nanoscale domains
Data Source
AI summary
Provided herein are copolymer electrolytes and electrocatalyst platforms, including brush block copolymers, triblock brush copolymers and pentablock brush copolymers. The copolymers described have beneficial chemical, physical and electrical properties including high ionic conductivity and mechanical strength. In embodiments, for example, the provided copolymer electrolytes and electrocatalyst platforms are doped with lithium salts or mixed with ionic liquids to form ion gels. In some embodiments, the copolymers provided herein self-assemble into physically cross-linked polymer networks with additional useful properties. The provided copolymers have low dispersity in the polymer side chains and do not require post-polymerization modifications.