Solid-State Battery Electrolyte Layout for Lower Interfacial Resistance
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Solution Overview
Problem
Lithium secondary batteries with liquid electrolytes are prone to fires and explosions due to short circuits, necessitating the development of solid electrolyte-based batteries for improved safety and stability.
Innovation Solution
A solid secondary battery design incorporating a cathode and anode layer with a solid electrolyte layer, and the use of high-viscosity organic electrolytes between and within these layers to reduce interfacial resistance and accommodate volume changes during charging and discharging, thereby enhancing cycling performance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid electrolytes are used in lithium secondary batteries, then ionic conductivity and electrochemical performance are improved, but safety deteriorates due to fire and explosion risks from short circuits
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid, fundamentally altering the safety characteristics while maintaining ionic conductivity through careful selection of solid electrolyte materials and their composition ratios
Solution Approach 2:
The patent creates a composite electrolyte system by combining solid electrolyte particles with binder material, forming a composite structure that integrates the high ionic conductivity of solid electrolytes with the mechanical flexibility and safety of binder materials, eliminating fire risks while maintaining performance
2Reliability
If solid electrolyte layers are used to improve safety, then fire risk is reduced, but interfacial resistance increases and cycling performance deteriorates
Solution Approach 1:
The patent applies local quality by creating heterogeneous regions within the solid electrolyte layer, where solid electrolyte particles are distributed in a binder matrix, providing locally optimized properties: high ionic conductivity at particle sites and mechanical continuity at binder sites, collectively reducing interfacial resistance
Solution Approach 2:
The patent utilizes a porous composite structure where solid electrolyte particles are dispersed within a binder material forming interconnected voids and channels, enabling efficient ion transport pathways while maintaining structural integrity and reducing contact resistance between electrode and electrolyte
3Reliability
If solid electrolyte layers are used to improve safety, then stability is enhanced, but volume change accommodation during charging and discharging deteriorates
Solution Approach 1:
The patent introduces dynamics by creating a flexible composite structure where the binder material can dynamically deform and accommodate volume changes of solid electrolyte particles during charging and discharging cycles, maintaining continuous ionic conduction pathways despite structural variations
Solution Approach 2:
The patent employs composite materials combining rigid solid electrolyte particles with flexible binder material, where the binder component provides mechanical compliance to accommodate volume expansion and contraction of solid electrolytes during electrochemical cycling, maintaining structural stability and ionic conductivity
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 battery design improves high-rate capability and lifespan by reducing interfacial resistance and suppressing defects in the solid electrolyte layer, leading to enhanced safety and performance.
Implementation Method 1
a first organic electrolyte between the cathode layer and the solid electrolyte layer, a second organic electrolyte between the anode layer and the solid electrolyte layer
Implementation Method 2
the liquid electrolyte having a viscosity of 10 cps or more at 25 °C and 1 atm... accommodate volume changes during charging and discharging
Data Source
Figure 1A~1B
Figure 1C~2A
Figure 2B~2C
AI summary
A solid secondary battery includes a cathode layer, an anode layer, and a solid electrolyte layer between the cathode layer and the anode layer and further includes a first organic electrolyte between the cathode layer and the solid electrolyte layer, a second organic electrolyte between the anode layer and the solid electrolyte layer, a third organic electrolyte in the solid electrolyte layer, or any combination thereof, wherein the first organic electrolyte, the second organic electrolyte, and the third organic electrolyte each independently include a polymer electrolyte, a liquid electrolyte, or any combination thereof, the liquid electrolyte having a viscosity of 10 cps or more at 25 °C and 1 atm, wherein the cathode layer includes a cathode current collector and a cathode active material layer on at least one surface of the cathode current collector, the cathode active material layer including a Li2S-containing composite.