Multiphase Metal Foil Anodes for Non-Aqueous Batteries
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Solution Overview
Problem
Current lithium-ion battery anodes face limitations in increasing gravimetric energy density due to low weight percentages of alloying compounds, poor cyclability, and volume changes, which compromise first cycle coulombic efficiency and rate capability.
Innovation Solution
Integrated metal foil anodes (IMFA) with a multiphase metallic system of active and conductive metals, such as aluminum-tin or zinc-tin, eliminate the need for a separate current collector, allowing for increased capacity and reduced volume expansion by selectively alloying with alkali or alkaline earth metals, thereby enhancing cyclability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If alloying compounds such as silicon, tin, germanium, and aluminum are added to graphite anodes to increase gravimetric energy density, then the theoretical capacity increases, but the low weight percentages and volume changes (>200%) with cycling compromise cyclability and coulombic efficiency
Solution Approach 1:
The patent merges the current collector function with the active alloying material by creating an integrated metal foil anode where the conductive metal matrix serves as both structural support and electrochemically active component. This eliminates the need for separate inactive current collector and reduces volume expansion issues.
Solution Approach 2:
The patent employs composite materials by creating a multiphase metallic system consisting of a conductive metal matrix (such as aluminum or zinc) with dispersed active alloying compounds (such as silicon, tin, germanium, or aluminum particles). This composite structure allows the conductive matrix to accommodate volume changes while the active particles provide high capacity.
2Quantity of substance
If higher theoretical capacity alloying compounds are added to increase energy density, then the capacity increases, but the low weight percentages limit the realized/utilized capacity
Solution Approach 1:
The patent applies local quality by creating a heterogeneous structure where active alloying compounds are distributed as particles within a conductive metal matrix. This ensures that active material is locally concentrated where needed while the conductive matrix provides continuous electron transport pathways throughout the anode structure.
Solution Approach 2:
The conductive metal matrix acts as an intermediary that facilitates electron transport between the active alloying compound particles and the current collector. This mediator ensures efficient charge transfer even when active material is distributed in small particles throughout the anode structure.
3Ease of manufacture
If materials with high ductility such as aluminum or tin are used to produce foils that act as both active material and current collector, then the foil production is enabled, but poor cyclability and low coulombic efficiency result due to large volume changes and undesired reactions with electrolyte
Solution Approach 1:
The patent changes the compositional parameters by creating a multiphase alloy system where the conductive metal matrix has optimized composition and microstructure. This allows the foil to maintain mechanical integrity and ductility for manufacturing while the specific alloy composition resists volume expansion and electrolyte reactions during cycling.
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 IMFA technology significantly increases effective capacity from 150 mAh/g to ≤300 mAh/g while minimizing volume expansion, improving cyclability and coulombic efficiency, and can be applied to various alkali metal and alkaline earth metal systems like sodium-ion, calcium-ion, and magnesium-ion batteries.
Implementation Method 1
a multiphase metallic system of at least one active material and a conductive metal... selectively alloying with alkali or alkaline earth metals
Data Source
AI summary
Disclosed herein are multiphase metal anodes useful in non-aqueous batteries. The anodes include at least one active metal and at least one conductive metal.