Porous Negative Current Collector for Lithium Dendrite Suppression
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Solution Overview
Problem
Lithium metal batteries face safety risks due to cyclic expansion and contraction of the cell system and the formation of lithium dendrites, which can lead to short circuits and safety hazards during charging and discharging.
Innovation Solution
A negative electrode current collector with porous channels filled with a lithium dissolving agent and a locking layer that constrains lithium ions, preventing their uneven deposition and reducing the formation of dendrites, thereby enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium ions are deposited during charging, then battery capacity increases, but volume expansion occurs and lithium dendrites form causing safety risks
Solution Approach 1:
The patent employs a porous current collector substrate with controlled pore size (5-50 μm) and porosity (30-80%) to accommodate lithium ions. The porous structure allows lithium ions to be stored within the pores during charging, preventing volume expansion of the overall battery structure and reducing the formation of lithium dendrites that cause safety issues.
Solution Approach 2:
The patent applies different materials to different parts of the current collector: a first material (lithium dissolving agent) is applied to the inner surface of the pores to dissolve and store lithium ions, while a second material (locking layer) is applied to the outer surface to constrain the lithium dissolving agent. This local differentiation resolves the contradiction by enabling safe lithium storage internally while maintaining structural integrity externally.
2Productivity
If a current collector is used to collect lithium ions, then charging efficiency improves, but cyclic expansion and contraction of the cell system occurs
Solution Approach 1:
The patent changes the physical state parameters of lithium storage from solid metal deposition to liquid/gel phase dissolution within porous structures. The lithium dissolving agent exists as a liquid or gel in the pores, allowing reversible absorption and release of lithium ions without the expansion and contraction associated with solid metal plating and stripping, thus maintaining cell system stability while preserving charging efficiency.
3Quantity of substance
If lithium dissolving agent is filled in pore channels, then lithium ion storage is improved, but device complexity increases due to additional locking layer and location inducing layer
Solution Approach 1:
The patent applies the locking layer and location inducing layer to the current collector substrate before filling it with the lithium dissolving agent. This preliminary action simplifies the overall process by pre-configuring the structural framework and functional layers, allowing the lithium dissolving agent to be simply infused into the pre-prepared porous structure rather than requiring complex assembly of multiple components.
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 reduces volume expansion and dendrite formation, significantly improving the safety and performance of lithium metal batteries by stabilizing lithium ions within the current collector's pore channels.
Implementation Method 1
a lithium dissolving agent filled in the pore channels of the current collector substrate, the lithium dissolving agent being a liquid or a gel capable of dissolving lithium metal
Implementation Method 2
a locking layer attached to a pore wall of the pore channel and located between the pore wall of the pore channel and the lithium dissolving agent, where the locking layer is configured to constrain the lithium dissolving agent to the pore channel
Implementation Method 3
The negative electrode current collector can lock lithium ions in the pore channels of the porous current collector substrate and stores them in the form of a liquid or a gel
Data Source
AI summary
A negative electrode current collector of a lithium metal battery includes a current collector substrate provided with a plurality of pore channels, a lithium dissolving agent filled in each of the pore channels of the current collector substrate, and a locking layer attached to a pore wall of a corresponding pore channel and located between the pore wall and the lithium dissolving agent. The lithium dissolving agent is a liquid or a gel capable of dissolving lithium metal. The locking layer is configured to constrain the lithium dissolving agent to the corresponding pore channel.