Sulfur-Bonded Negative Electrode Coating for Uniform Solid-State Batteries
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Solution Overview
Problem
Existing lithium ion batteries face safety concerns due to the use of combustible organic electrolyte solutions, and all-solid-state batteries, while safer, often suffer from non-uniform electrode coating layers that affect battery performance and lifetime.
Innovation Solution
A negative electrode coating layer composed of a metal-carbon composite chemically bonded through sulfur, with specific sulfur content and surface roughness, and controlled protrusion features, is used in an all-solid-state battery design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all-solid-state batteries replace electrolyte solution with solid electrolyte, then safety is improved, but electrode coating layer uniformity deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the coating layer by incorporating metal sulfide compounds (FeS, CoS, NiS, CuS, ZnS, or MnS) at specific content ratios (0.1-10 wt%). This chemical parameter modification enables the coating layer to achieve uniform thickness while maintaining compatibility with solid electrolyte, thus resolving the contradiction between safety improvement and coating uniformity
Solution Approach 2:
The invention creates a composite coating layer structure combining metal sulfide compounds with carbon materials (graphite, amorphous carbon, carbon nanotubes, or graphene) in specific ratios. This composite material approach ensures uniform coating formation on the negative electrode while maintaining the safety benefits of solid electrolyte, thereby resolving the uniformity issue without compromising safety
2Reliability
If metal and carbon-based material are chemically bonded through sulfur, then electrical conductivity is improved, but manufacturing complexity increases
Solution Approach 1:
The invention uses sulfur as an intermediary element to chemically bond metal particles with carbon-based materials. The metal sulfide compound acts as a bridging mediator that facilitates electrical conductivity between metal and carbon components while simplifying the manufacturing process compared to direct metal-carbon bonding, thus resolving the contradiction between conductivity improvement and manufacturing complexity
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 solution provides a uniform electrode coating layer, enhancing the battery's lifetime and safety by reducing the risk of short circuits and improving electrical conductivity.
Implementation Method 1
a metal-carbon composite in which a metal and a carbon-based material are chemically bonded through sulfur
Data Source
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AI summary
Provided are a negative electrode coating layer and an all-solid-state battery including the same, and, for example, a negative electrode coating layer for an all-solid-state battery, including a metal-carbon composite in which a metal and a carbon-based material are chemically bonded through sulfur, wherein a content of sulfur is 1,000 ppm to 10,000 ppm, and a root mean square roughness (Sq) of one surface is 0.6 µm or less.