Ceramic-Coated Separator for Lithium Metal Dendrite Suppression
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Solution Overview
Problem
Lithium metal batteries face challenges with dendrite formation and short circuits due to side reactions between lithium metal and electrolyte, leading to reduced lifespan and safety concerns, especially when using carbon-based anode active materials with low capacity.
Innovation Solution
A lithium metal battery design featuring a ceramic coating layer on one side of a porous substrate facing the anode current collector, combined with a gel-type polymer electrolyte in the pores, which inhibits dendrite growth and enhances electrolyte wettability, thereby improving lifespan and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal is used as anode active material to increase capacity, then theoretical capacity is improved, but dendrite formation occurs leading to short circuits and reduced lifespan
Solution Approach 1:
A ceramic coating layer is introduced as an intermediary between the lithium metal anode and the electrolyte. This coating layer acts as a mediator that prevents direct contact and harmful side reactions between lithium metal and electrolyte, thereby suppressing dendrite formation while maintaining the high capacity benefits of lithium metal.
Solution Approach 2:
The anode structure is designed as a composite material system combining lithium metal with a ceramic coating layer. This composite structure leverages the high capacity of lithium metal while the ceramic component provides structural stability and prevents dendrite growth, resolving the contradiction between capacity and reliability.
2Reliability
If ceramic coating layer is applied on both sides of porous substrate, then dendrite inhibition is enhanced, but electrolyte wettability and ion transport may be restricted
Solution Approach 1:
The ceramic coating layer is applied selectively only on the anode-facing side of the porous substrate rather than both sides. This local application ensures dendrite inhibition at the critical lithium metal interface while maintaining open pore structure on the cathode side for optimal electrolyte penetration and ion transport, thus balancing reliability and productivity.
3Reliability
If gel-type polymer electrolyte is used to inhibit dendrite formation, then lifespan is improved, but electrolyte wettability needs to be enhanced
Solution Approach 1:
The pore structure parameters of the porous substrate are optimized to enhance electrolyte wettability. By adjusting pore size distribution, porosity, and surface characteristics, the substrate facilitates better penetration and distribution of the gel-type polymer electrolyte, ensuring adequate ionic conductivity while maintaining the dendrite-inhibiting properties of the ceramic coating.
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 effectively inhibits lithium dendrite formation, improves long-term lifespan at both room and high temperatures, and maintains high energy density, reducing the risk of short circuits and enhancing the battery's overall performance.
Implementation Method 1
pores in the porous substrate may include a gel-type or kind polymer electrolyte
Implementation Method 2
improved electrolyte wettability by utilizing a separator which has a ceramic coating layer
Data Source
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AI summary
A lithium metal battery including: an anode current collector; a cathode; and a separator between the anode current collector and the cathode, wherein the lithium metal battery may include an anode active material layer between the anode current collector and the separator or may not include (e.g., may exclude or be free of) the anode active material layer, and the separator may include a porous substrate and a ceramic coating layer disposed on at least one side of the porous substrate, wherein the ceramic coating layer may be placed so as to face the anode current collector, and pores in the porous substrate may contain a gel-type or kind polymer electrolyte.