Battery Current Collector Protective Layer for Corrosion Resistance
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Solution Overview
Problem
Lithium-ion batteries with solid sulfide electrolytes face corrosion issues due to moisture, leading to the emission of harmful gases that corrode current collectors, particularly copper, necessitating protection from direct contact and gas exposure.
Innovation Solution
A protective layer is applied to the current collector, which is electronically conducting and insulates from Li+ ions, using materials like carbon, silicon, or chromium oxide, deposited via physical or chemical vapor deposition, to prevent corrosion from sulfide electrolytes and hydrogen sulfide gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the current collector is made of copper for negative electrode, then electrical conductivity is improved, but corrosion resistance against sulfide electrolyte deteriorates
Solution Approach 1:
A protective layer comprising carbon and/or silicon is introduced as an intermediary between the copper current collector and the sulfide electrolyte. This layer prevents direct contact between copper and corrosive sulfide/H2S, while maintaining electrical conductivity through its inherently conductive properties.
Solution Approach 2:
The current collector structure is transformed into a composite system with a copper substrate and a carbon/silicon protective coating. This composite structure combines the high electrical conductivity of copper with the corrosion resistance of carbon/silicon materials.
2Reliability
If a protective layer is added to protect the current collector, then corrosion resistance is improved, but electronic conductivity may deteriorate
Solution Approach 1:
The protective layer parameters (composition, thickness) are optimized to maintain electrical conductivity. By controlling the layer thickness to 1-100 nm and selecting conductive materials (carbon, silicon), the protective function is achieved without significantly increasing electrical resistance.
3Reliability
If the protective layer thickness is increased to improve corrosion protection, then corrosion resistance is improved, but Li+ ion insulation deteriorates
Solution Approach 1:
The layer thickness is precisely controlled within 1-100 nm range. This parameter optimization ensures sufficient corrosion protection while maintaining Li+ ion insulation functionality, as the thin layer is adequate to block ions but thin enough to allow electronic conduction.
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 protective layer effectively reduces corrosion and maintains electronic conductivity, enhancing the stability and efficiency of lithium-ion batteries by improving coulombic efficiency and preventing material degradation.
Implementation Method 1
the protective layer, which is electronically conducting and insulates from Li+ ions
Implementation Method 2
protect current collectors to avoid direct contact with a solid sulfide electrolyte
Implementation Method 3
deposited via physical or chemical vapor deposition
Implementation Method 4
deposited via physical or chemical vapor deposition
Data Source
AI summary
The present invention relates to a current collector for a negative electrode, coated with at least one electronically conducting and ionically insulating layer, to the method for producing such a collector, and to batteries containing same.