Block Polymer Electrolytes for Safer High-Voltage Batteries
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Solution Overview
Problem
Existing battery technologies face challenges with flammable liquid electrolytes, poor adhesion of polymer binders, and insufficient electrochemical stability, especially with high-capacity electrodes, leading to safety concerns and performance deterioration.
Innovation Solution
Development of polymers with a structure according to Formula I (A-B-A′) using ring-opening polymerization and copolymerization techniques, comprising polycarbonate and poly(ester-co-carbonate) blocks, which are environmentally friendly and provide enhanced mechanical and electrochemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flammable liquid electrolytes are used, then ionic conductivity is achieved, but safety concerns arise due to instability with high-capacity electrodes
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid polymer form, fundamentally altering the safety parameters while maintaining ionic conductivity through careful selection of polymer backbone structure and side groups
Solution Approach 2:
The patent employs composite polymer structures combining polycarbonate blocks for mechanical strength and poly(ester-co-carbonate) blocks for ionic conductivity, creating a material that simultaneously achieves safety and performance
2Strength
If PVDF polymer binder is used, then cathode particle adhesion is achieved, but flexibility and adhesion are insufficient for high-capacity cathodes undergoing expansion and contraction
Solution Approach 1:
The patent modifies the polymer binder structure by incorporating flexible poly(ester-co-carbonate) blocks with adjustable glass transition temperatures, enabling the binder to adapt to cathode volume changes while maintaining adhesion strength
Solution Approach 2:
The patent divides the polymer binder into distinct functional blocks: polycarbonate segments for structural integrity and poly(ester-co-carbonate) segments for flexibility and adhesion, allowing each segment to perform its specialized function
3Reliability
If PEO-based polymer electrolytes are used, then ion transport is achieved above Tg, but room temperature ionic conductivity is poor
Solution Approach 1:
The patent introduces side chains with terminal carboxylic acid groups that form hydrogen bonding networks, lowering the glass transition temperature and enabling ion transport at room temperature while preserving electrochemical stability
Solution Approach 2:
The patent uses hydrogen bonding as an intermediary mechanism to facilitate ion transport through the polymer matrix at low temperatures, where the hydrogen bond network creates pathways for lithium ion movement without requiring high thermal energy
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 new polymers demonstrate improved thermal stability, ionic conductivity, and adhesion, enabling compatibility with high-voltage cathodes and reducing safety risks, while maintaining excellent electrochemical performance.
Implementation Method 1
Ion transport only occurs in amorphous regions above the Tg as it is assisted by the segmental motion of the polymer chains
Implementation Method 2
the ether oxygens are good donors so are able to solvate Li+
Implementation Method 3
performing ring-opening polymerisation of: (i) a cyclic carbonate or (ii) a mixture of a cyclic carbonate and a cyclic ester to form a polymeric block
Implementation Method 4
growing a polymeric block A on one or both ends of the polymeric block B by ring-opening copolymerisation of: (i) an epoxide or an oxetane, and (ii) carbon dioxide
Data Source
AI summary
New block polymers are described, as well as processes for preparing them using ring-opening polymerisation and ring-opening copolymerisation techniques. Also described are electrolytes, cathodes and batteries comprising the polymers.