Solid Electrolyte Composites for Battery Interface Impedance
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Solution Overview
Problem
Solid-state lithium ion batteries face limitations in ionic conductivity and interfacial impedance, leading to inadequate power performance and low capacity due to the use of polymeric solid-state electrolytes like PEO, which restrict lithium ion transport across interfaces in the battery components.
Innovation Solution
The use of specific lithium salts, such as lithium bis(oxalato)borate or lithium bis(trifluoromethanesulfonyl)imide, in combination with poly(ethylene oxide) (PEO) and ceramic materials, to form cathode and electrolyte composites that reduce impedance and enhance lithium ion conductivity, thereby improving battery capacity and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymeric solid-state electrolytes like PEO are used, then safety is improved and liquid-tight sealing is eliminated, but ionic conductivity is insufficient for practical power performance
Solution Approach 1:
The patent uses composite materials by combining polymeric solid electrolyte (PEO) with ceramic particles (alumina, silica, titania) to create a composite solid electrolyte that maintains the safety advantages of solid polymers while improving ionic conductivity through the ceramic component, achieving both reliability and power performance
2Power
If thin film structures are used to achieve successful solid-state batteries, then ionic conductivity is improved, but energy density is reduced
Solution Approach 1:
The patent changes the compositional parameters of the solid electrolyte by incorporating ceramic particles with specific properties (alumina, silica, titania) into the polymeric matrix, modifying the ionic conductivity parameter without requiring thin film geometry, thus maintaining energy density while achieving practical power performance
3Device complexity
If substantial interfaces are present among solid battery components, then battery structure is formed, but lithium ion transport is limited and impedance increases
Solution Approach 1:
The patent uses ceramic particles (alumina, silica, titania) as intermediary materials at the interfaces between electrode and electrolyte, creating intermediate layers that facilitate lithium ion transport across interfaces, reducing interfacial impedance and improving overall battery performance while maintaining structural integrity
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 proposed solution achieves high capacity and low impedance in solid-state batteries, enabling nearly theoretical discharge rates and stable ionic conductivity, with lithium salt migration improving interfacial transport and reducing impedance across battery interfaces.
Implementation Method 1
PEO has the ability to conduct lithium ions as positive lithium ions are solubilized and/or complexed by the ethylene oxide groups on the polymer chain
Implementation Method 2
Solid electrolytes formed from PEO can have crystalline and amorphous regions, and it is believed that lithium ions move preferentially through the amorphous portion of the PEO material
Data Source
AI summary
A lithium ion battery having an anode, a solid electrolyte, and a cathode. The cathode includes an electrode active material, a first lithium salt, and a polymer material. The solid electrolyte can include a second lithium salt. The solid electrolyte can include a ceramic material, a lithium salt, and a polymer material.