Composite Solid Electrolyte Layer for Crack-Resistant Solid-State Batteries
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Solution Overview
Problem
All-solid-state secondary batteries face challenges with short circuits and deteriorated cycle characteristics due to defects in the solid electrolyte layer, which are exacerbated by pressure imbalances during manufacturing and charging/discharging processes.
Innovation Solution
Incorporating inorganic particles with an average diameter of 50 nm to 5 μm in the sulfide-based solid electrolyte layer to enhance contact and reduce defects, thereby preventing short circuits and improving discharge capacity and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sulfide-based solid electrolyte is used in all-solid-state batteries, then safety is improved by eliminating flammable organic solvents, but defects and cracks occur in the solid electrolyte layer during manufacturing and charging/discharging processes
Solution Approach 1:
The patent uses a composite solid electrolyte layer combining sulfide-based solid electrolyte particles with oxide-based solid electrolyte particles. The sulfide-based electrolyte provides high ionic conductivity and safety, while the oxide-based electrolyte acts as a spacer that prevents defects and cracks, creating a synergistic composite material that resolves the contradiction between safety and structural integrity
Solution Approach 2:
The patent introduces oxide-based solid electrolyte particles with different properties (higher mechanical strength and stability) into specific regions of the solid electrolyte layer. These oxide particles are distributed throughout the sulfide-based electrolyte matrix, providing local reinforcement and defect prevention where needed, while maintaining the overall safety benefits of the sulfide-based electrolyte
2Stability of the object's composition
If oxide-based solid electrolyte particles are added as spacer particles, then defects are suppressed, but lithium ion conductivity decreases
Solution Approach 1:
The patent carefully controls the particle size parameters of the oxide-based solid electrolyte particles, specifying an average particle diameter of 0.1 μm to 10 μm. This parameter optimization ensures that the oxide particles are small enough to maintain good contact and ionic pathways while being large enough to effectively act as spacers and prevent defects, thus balancing defect suppression with ionic conductivity
Solution Approach 2:
The patent creates a composite structure where oxide-based particles are dispersed in a sulfide-based electrolyte matrix. The sulfide-based electrolyte constitutes the majority of the composite and provides the primary ionic conduction pathway, while the oxide particles are present in sufficient quantity to suppress defects but in a distribution and size range that minimizes their blocking effect on ionic conductivity
3Stability of the object's composition
If high-temperature heat treatment is applied to prepare sulfide-based solid electrolyte with alumina, then material stability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent incorporates oxide-based solid electrolyte particles into the solid electrolyte layer during the initial mixing and coating stages, before the final sintering process. This preliminary incorporation ensures that the oxide particles are properly distributed and positioned to prevent defects from the outset, eliminating the need for subsequent high-temperature heat treatment steps that would be required if defects developed during operation
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 use of inorganic particles in the solid electrolyte layer suppresses defects and cracks, maintaining low internal resistance and enhancing the battery's discharge capacity and cycle characteristics.
Implementation Method 1
the inorganic particles have an average particle diameter of 50 nm to 5 μm or less... suppresses defects and cracks
Data Source
AI summary
Provided are an all-solid-state secondary battery including a cathode layer, an anode layer, and a solid electrolyte layer disposed between the cathode layer and the anode layer, wherein the solid electrolyte layer includes a sulfide-based solid electrolyte and inorganic particles, wherein the inorganic particles have an average particle diameter of 50 nm to 5 μm or less, and a method of manufacturing the same.