Nitrogen-Doped Carbon Coating for Solid-State Lithium Anodes
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Solution Overview
Problem
The growth of lithium dendrites during charging and discharging processes in all-solid-state batteries using lithium as an anode active material leads to short circuits and reduced battery capacity, posing significant challenges for commercialization.
Innovation Solution
An all-solid-state battery design incorporating a coating layer made of nitrogen-containing amorphous carbon, with specific nitrogen content and particle characteristics, is used to suppress lithium dendrite growth and improve charge/discharge characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium is used as the anode active material to increase energy density, then the energy density of the all-solid-state battery is improved, but lithium dendrites grow through gaps in the solid electrolyte layer during charging and discharging, leading to short circuits or reduced battery capacity
Solution Approach 1:
A coating layer comprising amorphous carbon is introduced as an intermediary between the lithium anode active material and the solid electrolyte layer. This coating layer prevents direct contact and interaction between lithium and the solid electrolyte, thereby suppressing dendrite growth and eliminating short circuits while maintaining the high energy density benefits of lithium anode
Solution Approach 2:
The coating layer is formed using composite materials including amorphous carbon, conductive polymer, and lithium salt, which combine the advantages of different materials to achieve both high conductivity and effective dendrite suppression, resolving the contradiction between energy density and reliability
2Reliability
If a coating layer comprising amorphous carbon is formed on the anode current collector to suppress lithium dendrite growth, then battery reliability is improved, but lithium diffusion resistance increases
Solution Approach 1:
The coating layer's physical and chemical parameters are optimized by controlling the amorphous carbon particle size (average 10-100 nm), nitrogen content (0.5-7 atomic%), and layer thickness (1-20 μm). These parameter adjustments reduce lithium diffusion resistance while maintaining effective dendrite suppression
Solution Approach 2:
The coating layer is designed with non-uniform local properties, including nitrogen-doped regions for enhanced conductivity and specific particle size distributions, creating locally optimized zones that facilitate lithium diffusion while preventing dendrite formation in critical areas
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 battery exhibits excellent capacity retention and high-rate charging performance by minimizing lithium diffusion resistance and irreversible reactions, thereby enhancing battery stability and lifespan.
Implementation Method 1
the amorphous carbon comprises a nitrogen-containing amorphous carbon, and wherein a nitrogen amount (atomic %) included in the coating layer ranges from 0.5% to 7%
Implementation Method 2
90% or more of nitrogen in the nitrogen-containing amorphous carbon may be located within a depth of 5 nm from the surface of the nitrogen-containing amorphous carbon
Data Source
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AI summary
The present invention relates to an all-solid-state battery comprising a positive electrode, a solid electrolyte layer, a coating layer, and a negative electrode current collector, wherein the coating layer comprises amorphous carbon, the amorphous carbon comprises nitrogen-containing amorphous carbon, and the nitrogen content (atomic %) contained in the coating layer is in the range of 0.5% to 7%. The all-solid-state battery according to the present invention may have an excellent capacity retention rate according to cycles during high-rate charging and discharging.