Solid-State Battery Anode Carbon Network for Resistance Stability
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Solution Overview
Problem
Conventional all-solid-state batteries experience a high resistance increase ratio after long-term use, leading to battery deterioration.
Innovation Solution
The use of an alloy-based active material anode combined with two types of fibrous carbons, where the first fibrous carbon has a larger fiber diameter and the second fibrous carbon has a smaller fiber diameter, with a specific ratio and proportion to form both broad and minute paths, effectively reducing the resistance increase ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If alloy-based active material is used for anode, then battery capacity is improved, but resistance increase ratio becomes high after long-term use
Solution Approach 1:
The patent divides the conductive network into two segments: spherical carbon particles (150 nm or less) forming a fine distributed network for minute paths, and fibrous carbon (10 μm or more length) forming a coarse network for broad paths. This segmentation allows each component to specialize in one function, preventing the resistance increase that occurs when a single material tries to perform both functions
Solution Approach 2:
The patent creates a composite conductive network combining two different carbon materials with complementary properties. The spherical carbon provides extensive surface coverage and fine pathways, while the fibrous carbon provides structural integrity and broad pathways. This composite structure maintains low resistance even after long-term use when the alloy-based active material undergoes volume changes
2Strength
If fibrous carbon is used to form broad paths, then crack connection is improved, but minute path coverage is insufficient
Solution Approach 1:
The patent segments the conductive network function between two carbon types: fibrous carbon handles the broad path function for crack connection, while spherical carbon handles the minute path function for comprehensive particle coverage. This segmentation resolves the contradiction by allowing each material to excel at its designated function without compromise
Solution Approach 2:
The patent applies different carbon materials to different spatial scales within the electrode structure. Fibrous carbon operates at the macro scale to bridge cracks and provide structural conductivity, while spherical carbon operates at the micro scale to coat individual active material particles. This local quality differentiation allows both broad path and minute path requirements to be satisfied simultaneously
3Area of stationary object
If spherical carbon is used to form minute paths, then particle coverage is improved, but broad path formation is insufficient
Solution Approach 1:
The patent segments the conductive network into two functional components: spherical carbon for minute path formation that covers particle surfaces, and fibrous carbon for broad path formation that connects regions. This segmentation allows spherical carbon to focus on comprehensive particle coverage without needing to provide structural broad path connectivity
Data Source
AI summary
Provided is an all-solid-state battery capable of suppressing a rise in the resistance increase ratio thereof. The all-solid-state battery includes an anode active material layer containing an alloy-based active material, a first fibrous carbon, and a second fibrous carbon, wherein when a fiber diameter of the first fibrous carbon is defined as A, and a fiber diameter of the second fibrous carbon is defined as B, the ratio of A to B is 10 to 300, and when the proportion (wt %) of the first fibrous carbon to the alloy-based active material is defined as X, and the proportion (wt %) of the second fibrous carbon to the alloy-based active material is defined as Y, the proportion ({Y/(X+Y)}×100%) of the contained second fibrous carbon to a total of the first fibrous carbon and the second fibrous carbon is 0.5% to 10%.