Lithium Secondary Battery Buffer Layer for Stable Li Deposition
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Solution Overview
Problem
Lithium metal anodes in batteries experience dendrite growth leading to micro-shorts and degradation, necessitating a solution to control dendrite formation and mitigate volume changes during charge/discharge cycles.
Innovation Solution
A lithium secondary battery design incorporating a Li buffer layer with high Li-ion conductivity and low electrical conductivity, combined with a porous structure at the anode, guides lithium deposition and maintains porosity under compressive stress to prevent dendrite formation and stabilize volume changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal anode is used to achieve high capacity, then battery energy density is improved, but dendrite growth occurs leading to micro-shorts and degradation
Solution Approach 1:
A buffer layer composed of lithium fluoride (LiF) and lithium chloride (LiCl) is introduced between the lithium metal anode and the Li-ion electrolyte layer. This intermediary buffer layer modifies the interface properties, controlling lithium ion deposition to prevent dendrite formation while maintaining high lithium capacity.
2Quantity of substance
If lithium metal anode undergoes charge/discharge cycles to provide high energy density, then battery capacity is improved, but volume changes occur leading to structural degradation
Solution Approach 1:
A porous layer with porosity of 30-70% is introduced at the anode, positioned between the lithium metal anode and the current collector. This porous structure accommodates volume changes during charge/discharge cycles by providing void space for lithium expansion and contraction, thereby maintaining structural stability while preserving battery capacity.
3Stability of the object's composition
If buffer layer is compressed to maintain porosity of porous layer, then volumetric stability is improved, but manufacturing complexity increases
Solution Approach 1:
The buffer layer is pre-compressed during the battery assembly process to establish and maintain the required porosity of the porous layer. By applying compression force during manufacturing rather than requiring continuous active compression mechanisms, the design simplifies the overall system while ensuring volumetric stability during operation.
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 design achieves stable charge/discharge performance and prolonged battery life by preventing dendrite formation and controlling volume changes, suitable for applications requiring high capacity and long cycle lifetime.
Implementation Method 1
the Li buffer layer provides high Li-ion conductivity and low electrical conductivity
Implementation Method 2
The Li buffer layer is compressed between the Li metal anode and the electrolyte layer at a pressure of at least 0.1 MPa (megapascal) to maintain the porosity of the porous layer
Implementation Method 3
a porous layer positioned between the Li metal anode and the anode current collector. The Li buffer layer is compressed between the Li metal anode and the electrolyte layer at a pressure of at least 0.1 MPa (megapascal) to maintain the porosity of the porous layer
Implementation Method 4
The Li buffer layer is compressed between the Li metal anode and the electrolyte layer at a pressure of at least 0.1 MPa (megapascal)
Data Source
AI summary
A lithium (Li) secondary battery having a Li buffer layer compressed between a Li metal anode and an electrolyte of the battery cell and a porous structure positioned between the Li metal anode and a current collector of the battery cell. The Li buffer layer is effective in preventing uncontrollable dendrite growth. The porous structure layer is effective in guiding the location of the Li deposition, thereby reducing the volume changes of the Li anode during the charge and discharge cycles of the lithium secondary battery.