Porous Support Lithium Composite Electrode
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Solution Overview
Problem
The use of metallic lithium in electrodes for batteries is hindered by its softness, adherence to structural materials, low mechanical strength, dendrite formation, and excessive electrolyte reduction, which limits specific energy and mechanical properties, making it challenging to produce thin lithium foils and maintain electrochemical performance.
Innovation Solution
A permeable composite material is developed, comprising a support with pores and an alkali metal deposit, enhancing mechanical strength and electrochemical performance by allowing uniform electrolyte penetration and dispersion of alkali metal, thereby improving specific energy and cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If metallic lithium is used in electrodes to increase specific energy, then the specific energy of the battery increases, but the mechanical strength and handling properties deteriorate due to extreme softness and plasticity
Solution Approach 1:
The patent applies composite materials by combining metallic lithium with a porous support structure (such as carbonaceous materials, metal foams, or ceramic frameworks). This composite approach allows the lithium to maintain its high energy density while the support structure provides mechanical strength and structural integrity, resolving the contradiction between high specific energy and mechanical strength
Solution Approach 2:
The patent utilizes porous materials as the support structure for metallic lithium. The porous architecture provides both mechanical support and adequate surface area for electrochemical reactions. The pore structure allows electrolyte penetration while maintaining the lithium's mechanical stability, thus improving both mechanical strength and electrochemical performance simultaneously
2Use of energy by moving object
If metallic lithium is used to achieve high specific energy, then energy density increases, but dendrite formation occurs which reduces specific energy and causes safety issues
Solution Approach 1:
The porous support structure distributes the metallic lithium deposition uniformly across the pore surfaces, preventing localized dendrite growth. The three-dimensional pore architecture provides multiple nucleation sites that promote uniform lithium plating during charging, thereby eliminating dendrite formation while maintaining high specific energy
Solution Approach 2:
The porous support structure acts as an intermediary between the metallic lithium and the electrolyte. It mediates the electrochemical reactions by providing a stable substrate that controls lithium ion deposition, preventing direct uncontrolled growth of dendrites while still allowing efficient charge transfer
3Use of energy by moving object
If metallic lithium is used to increase specific energy, then energy density improves, but excessive electrolyte reduction occurs leading to passivation and reduced specific energy
Solution Approach 1:
The porous support structure increases the effective surface area for electrochemical reactions, distributing the current density more uniformly. This reduces localized excessive electrolyte reduction and passivation, improving both energy efficiency and specific energy retention over cycling
4Use of energy by moving object
If lithium foils are calendared to reduce thickness to decrease mass, then specific energy increases, but manufacturing becomes difficult due to poor mechanical properties
Solution Approach 1:
The composite structure of metallic lithium on porous support provides inherent mechanical stability, eliminating the need for extreme thinning through calendaring. The support structure acts as a scaffold that maintains structural integrity, allowing easier handling and manufacturing while still achieving low mass and high specific energy
Solution Approach 2:
The porous support structure provides mechanical strength that allows the lithium electrode to be manufactured without requiring extreme calendaring processes. The three-dimensional pore architecture naturally reduces mass while maintaining structural integrity, simplifying manufacturing compared to ultra-thin calendared foils
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 composite material provides a mechanically strong and lightweight electrode with improved electrochemical properties, including increased energy density and extended cycle life, while reducing the overall mass of lithium, thus addressing the limitations of metallic lithium in battery electrodes.
Implementation Method 1
a support defining pores; and an alkali metal deposit on the support within a plurality of said pores
Data Source
AI summary
A permeable composite material for making an electrode for an electrochemical cell, the composite material comprising: a support defining pores; and alkali metal deposited on the support within a plurality of said pores. An electrode comprising the composite material is also described, as are methods of making the material and cells and assemblies comprising the electrode.