Solid-State Battery Cathode Composite for Conductive Safety
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Solution Overview
Problem
Existing lithium batteries with liquid electrolytes are susceptible to overheating and flammability, posing safety risks, particularly in applications like vehicles where safety is critical.
Innovation Solution
The development of an all-solid secondary battery using a solid electrolyte instead of a liquid electrolyte, which includes a positive electrode composed of a composite positive active material. This composite material comprises M2S, an alkali metal salt, a two-dimensional carbonaceous nanostructure, and a fibrous carbonaceous material with an aspect ratio of 2 or more, enhancing electronic conduction and ion conduction pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid electrolyte is used in a lithium battery, then the battery can operate with conventional liquid electrolyte technology, but the battery is susceptible to overheating and flammability risks
Solution Approach 1:
The patent changes the physical state parameter of the electrolyte from liquid to solid, fundamentally altering the safety characteristics of the battery system. This phase change eliminates the flammability and overheating risks associated with liquid electrolytes while maintaining ionic conductivity through solid-state ion transport mechanisms.
Solution Approach 2:
The patent employs composite materials by combining solid electrolyte with carbonaceous materials (graphene, carbon nanotubes, carbon fibers) to create a composite positive active material. This composite structure provides both the safety benefits of solid electrolyte and the enhanced electronic conduction pathways of carbon materials, resolving the contradiction between safety and performance.
2Reliability
If a solid electrolyte is used in an all-solid secondary battery, then the safety profile is improved by reducing overheating and flammability risks, but the electronic conduction network needs enhancement to maintain performance
Solution Approach 1:
The patent creates a composite positive active material that integrates solid electrolyte particles with conductive carbonaceous materials (graphene, carbon nanotubes, carbon fibers) and positive active material particles. This composite structure provides dual functionality: the solid electrolyte ensures safety by eliminating liquid electrolyte risks, while the carbonaceous network ensures sufficient electronic conduction for high energy density and specific capacity.
Solution Approach 2:
The patent applies local quality by creating distinct functional regions within the composite material: solid electrolyte regions provide ionic conduction and safety, carbonaceous material regions provide electronic conduction pathways, and positive active material regions provide electrochemical activity. This spatial differentiation of functions allows the material to simultaneously achieve safety and high performance.
3Power
If a composite positive active material with carbonaceous materials is used, then the electronic conduction network is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges multiple materials (positive active material, solid electrolyte, and carbonaceous materials) into a single composite positive active material that can be processed as one integrated component. This combining approach simplifies manufacturing by eliminating the need for separate assembly steps for each material, reducing device complexity while maintaining the performance benefits of the composite structure.
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 all-solid secondary battery achieves improved initial efficiency, specific capacity, energy density, and lifespan due to the enhanced electronic and ion conduction networks, while also providing a safer alternative by reducing the risk of overheating and flammability.
Implementation Method 1
a composite that includes an M 2S, an alkali metal salt, a two-dimensional carbonaceous nanostructure, and a fibrous carbonaceous material with an aspect ratio of 2 or more
Implementation Method 2
an electrolyte layer provided between the positive electrode and the negative electrode
Data Source
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AI summary
A solid secondary battery including a positive electrode, a negative electrode, and an electrolyte layer provided between the positive electrode and the negative electrode is provided. The positive electrode includes a positive current collector, and a positive active material layer provided on at least one side of the positive current collector, the positive active material layer includes a composite positive active material that includes M2S, an alkali metal salt, a two-dimensional carbonaceous nanostructure, and a fibrous carbonaceous material with an aspect ratio of 2 or more, where M is Li or Na. The two-dimensional carbonaceous nanostructure includes graphene, a graphene oxide, a reduced graphene oxide, or a combination thereof, and the composite positive active material includes a solid solution of M2S and the alkali metal salt.