Textured Lithium Foils for Dendrite-Stable Metal Anodes
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Solution Overview
Problem
The growth of lithium dendrites in Li-metal anodes leads to poor cycle life and safety issues in batteries, limiting their practical application due to uneven electrode surfaces and potential short-circuits.
Innovation Solution
The preparation of Li or Na foils with {110} or {100} surface texturing through annealing, polishing, and rolling processes to achieve preferential crystallographic orientations, which stabilizes the surface and enhances nucleation and growth of lithium, reducing dendrite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If Li-metal anode is used to achieve high energy density, then energy density is improved, but lithium dendrite growth occurs leading to poor cycle life and safety issues
Solution Approach 1:
The patent applies local quality by creating specific crystallographic orientations ({100} and especially {110} planes) on different regions of the Li-metal anode surface. This texturing creates uniform nucleation sites with controlled surface energies, ensuring homogeneous Li deposition throughout the electrode rather than random dendritic growth, thereby improving cycle life while maintaining high energy density.
Solution Approach 2:
The patent changes the crystallographic parameter of the Li-metal surface by controlling the exposure of specific crystal planes ({100} and {110}) through annealing and mechanical processing. This parameter change in surface orientation fundamentally alters the nucleation and growth behavior of Li, suppressing dendrite formation and improving reliability without sacrificing energy density.
2Use of energy by moving object
If Li-metal anode is used to achieve high energy density, then energy density is improved, but safety issues arise due to dendrite-induced short-circuits
Solution Approach 1:
By creating uniform local crystallographic structures ({110} and/or {100} planes) across the Li-metal surface, the patent eliminates random high-energy sites that would otherwise promote dendrite initiation. This controlled local quality ensures uniform Li plating and prevents the formation of sharp dendrites that could pierce separators and cause short-circuits, thereby improving safety while maintaining high energy density.
Solution Approach 2:
The patent applies preliminary anti-action by pre-texturing the Li-metal surface with specific crystal orientations before battery assembly and operation. This pre-established uniform surface structure proactively prevents dendrite formation from the outset, counteracting the inherent tendency of Li to form dendrites during cycling, thus eliminating safety hazards before they can occur.
3Reliability
If severe plastic deformation is applied to create Li {100} texturing, then cycle performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent changes the crystallographic parameters of Li foils by controlling annealing temperature and duration, as well as the degree of cold rolling. By optimizing these parameters, the patent achieves desired texturing ({100} or especially {110} planes) through relatively simple thermal and mechanical processes, improving cycle performance without excessive manufacturing complexity.
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 {110} texturing significantly improves the cycle stability and safety of Li or Na metal electrodes, maintaining surface flatness and uniform deposition/stripping even at high current densities, outperforming electrodes without texturing and achieving comparable performance to those with artificial solid electrolyte interfaces.
Implementation Method 1
A lithium or sodium metal foil is provided with a thickness of about 600 μm which undergoes as needed the first annealing to a first temperature of about 70 to 90 percent of the melting point of the alkali metal foil
Implementation Method 2
The surface of the foil is polished using a chemical polishing solution, such as a naphthalene tetrahydrofuran solution
Implementation Method 3
For {110} texture, a first rolling is carried out at room temperature on the foil till the foil is about 300 μm in thickness
Implementation Method 4
The surface is scrapped along the same axis as the first rolling such that about 50 μm in thickness is removed from the alkali metal foil at a temperature of about 70 percent of the melting point of the alkali metal foil
Implementation Method 5
pressing was carried out using a hydraulic press at room temperature. The pressure varied for different alkali metal, such as about 5 MPa for lithium or 3 MPa for sodium
Data Source
AI summary
A method of forming a lithium or sodium foil for use as an electrode involves imposing a surface texturing that is predominately the {110} or {100} crystallographic orientation. For a Li {110} foil, a raw foil with a thickness of about 600 μm is heated to about 90° C. to randomize the crystallographic orientation and the foil is rolled to about 300 μm upon cooling. The rolled film is then scraped of about 50 μm of the lithium surface and heated to about 75° C. and rolled a second time to about 200 μm, and again cooled to room temperature. The cooled foil can be shaped into the electrode. The electrode can be employed in a battery to greatly extend the life of the battery relative to a lithium battery with a lithium anode that lacks the surface texturing. The alkali metal can be lithium electrochemically deposited on 3D scaffold such as carbon cloth with the deposited alkali metal maintaining the {110} texture.