Crosslinked Polysiloxane Electrolyte for Dendrite Blocking
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Solution Overview
Problem
Current lithium-ion batteries face safety issues at high charge/discharge rates due to intense heat release and limited ionic conductivity, mechanical stability, and dendrite formation, which restrict their use in high-rate applications like electric vehicles and renewable energy storage.
Innovation Solution
A composite solid-state electrolyte is developed, comprising a crosslinked lithium ion conducting polymer matrix with polysiloxanes and lithium ion conducting particles, which provides high ionic conductivity and mechanical strength, integrated with porous electrodes to enhance interfacial properties and prevent dendrite shorting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If PEO-based polymer electrolytes are used to block lithium dendrites, then mechanical strength is improved, but lithium ion conductivity deteriorates to about 10^-7-10^-9 S/cm
Solution Approach 1:
The patent employs a composite solid-state electrolyte consisting of a crosslinked polymer matrix combined with inorganic lithium ion conducting particles. This composite structure allows the polymer to provide mechanical strength for dendrite blocking while the inorganic particles contribute high ionic conductivity, achieving both requirements simultaneously rather than relying on PEO polymer alone.
Solution Approach 2:
The patent changes the physical and chemical parameters of the electrolyte by using crosslinked polymer networks with controlled crosslinking density and incorporating inorganic particles with specific conductivity values. This parameter optimization enables the electrolyte to achieve both sufficient mechanical strength and acceptable ionic conductivity for battery applications.
2Productivity
If high charge/discharge rates are used to increase drivability and energy harvest, then productivity is improved, but thermal safety deteriorates due to intense heat release and thermal runaway
Solution Approach 1:
The patent replaces the traditional liquid organic electrolyte system with a solid-state electrolyte system. This substitution eliminates the flammable organic components that cause thermal runaway at high rates, while the solid-state electrolyte's inherent stability allows the battery to operate safely at high charge/discharge rates required for electric vehicle applications.
3Device complexity
If thin-film solid state lithium ion batteries are used, then device complexity is reduced, but performance deteriorates due to insufficient active sites at two dimensional interfaces
Solution Approach 1:
The patent transitions from two-dimensional planar electrode interfaces to three-dimensional porous electrode structures with interconnected pathways. This dimensional change dramatically increases the effective interfacial area between electrodes and electrolyte, providing sufficient active sites for high-rate charge/discharge while maintaining a relatively simple overall battery structure.
4Strength
If less conductive ceramics are used as porous three dimensional support, then mechanical strength is improved, but current collection deteriorates thus constraining rate capacity
Solution Approach 1:
The patent creates a composite electrode structure combining porous ceramic supports with conductive materials. The ceramic provides the necessary mechanical strength and porous three-dimensional structure, while the incorporated conductive materials ensure efficient current collection throughout the electrode volume, enabling both structural integrity and high rate capacity.
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 solution enables high energy density, high cycling rates, and improved safety for lithium-ion batteries, addressing the limitations of existing technologies by providing a stable and robust solid-state electrolyte that prevents thermal runaway and extends battery lifespan.
Implementation Method 1
side chains pendant to the backbone that include lithium ion chelating functionality (e.g., polyether functionality or carbonate functionality) that facilitates lithium ion conductivity across the electrolyte
Implementation Method 2
The shear modulus of the polymer must be at least twice that of lithium metal to sufficiently block the mechanical attack by lithium dendrites
Data Source
AI summary
Solid state lithium ion conducting electrochemical cells and methods for forming the cells are described. The electrochemical cells include a composite solid state lithium ion conducting electrolyte separating porous metal supported electrodes. The electrolyte includes a crosslinked oligosiloxane matrix that includes pendant lithium ion chelating functionality that is provided in conjunction with lithium ions and encapsulating lithium ion conducting particles. The solid state electrolyte can extend into the pores of the electrodes to provide high surface area contact and improved electrochemical characteristics.