All-solid-state lithium ion battery anode with controlled electrolyte surface area
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Solution Overview
Problem
All-solid-state lithium ion secondary batteries using alloy-based active materials exhibit low capacity retention rates due to uneven distribution of electroconductive materials caused by small particle diameters of solid electrolytes, leading to compromised electron conductivity paths during charge-discharge cycles.
Innovation Solution
Incorporating an anode active material that can form alloys with Li, along with a sulfide solid electrolyte with a specific BET specific surface area of 1.8 m2/g to 19.7 m2/g and an electroconductive material like carbon nanotubes or carbon nanofibers, to maintain balanced ion and electron conductivity paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If small particle diameter solid electrolyte is used, then ion conductivity is improved, but electroconductive material distribution becomes uneven
Solution Approach 1:
The patent changes the particle size parameter of the solid electrolyte from small (high surface area) to a controlled range (3-10 μm average particle diameter), which balances ion conductivity with uniform electroconductive material distribution, preventing the aggregation issue while maintaining performance
Solution Approach 2:
The patent creates a composite anode structure containing alloy-based active material particles, solid electrolyte particles, and electroconductive material, where the solid electrolyte acts as a matrix that uniformly distributes the electroconductive material while providing ion conduction pathways
2Quantity of substance
If alloy-based active material is used, then capacity is improved, but capacity retention rate deteriorates during charge-discharge cycles
Solution Approach 1:
The patent applies local quality by creating distinct regions in the anode: alloy-based active material particles for high capacity, solid electrolyte particles for ion conduction and structural stability, and electroconductive material for electron transport, where each component performs its specific function to maintain overall performance during cycling
Solution Approach 2:
The patent incorporates solid electrolyte and electroconductive material in advance within the anode structure before cycling begins, pre-establishing ion conduction pathways and electron transport networks that prevent capacity degradation during subsequent charge-discharge cycles
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
This configuration enhances cycle characteristics and maintains high capacity retention rates by preventing uneven distribution of electroconductive materials and maintaining electron conductivity paths during volume changes associated with Li insertion/extraction reactions.
Implementation Method 1
an anode that comprises, as an anode active material, at least one active material selected from the group consisting of a metal that is able to form an alloy with Li, an oxide of the metal, and an alloy of the metal and Li
Implementation Method 2
a metal that is able to form an alloy with Li... Li insertion/extraction reactions
Data Source
AI summary
Disclosed is an all-solid-state lithium ion secondary battery including an anode that contains, as an anode active material, at least one selected from the group consisting of a metal that is able to form an alloy with Li, an oxide of the metal, and an alloy of the metal and Li, and being excellent in cycle characteristics. The all-solid-state lithium ion secondary battery may be an all-solid-state lithium ion secondary battery, wherein an anode comprises an anode active material, an electroconductive material and a solid electrolyte; wherein the anode active material comprises at least one active material selected from the group consisting of a metal that is able to form an alloy with Li, an oxide of the metal, and an alloy of the metal and Li; and wherein the solid electrolyte is particles with a BET specific surface area of from 1.8 m2/g to 19.7 m2/g.