Buffering Zone Anode Coatings for Fast Charging Safety
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Solution Overview
Problem
Lithium ion batteries face safety risks due to thermal runaway, cell breakdown, and the potential for fire or explosion, particularly when overheated or overcharged, and are prone to lithium metallization and dendrite growth, which can lead to battery failure.
Innovation Solution
The development of an anode with a buffering zone that partly masks the positive charge of lithium ions, allowing them to move into the anode material for lithiation, using electron donating groups interspaced with non-electron donating groups at a specific ratio to prevent lithium ion accumulation and dendrite growth, thereby enhancing safety and enabling fast charging rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium ion batteries use conventional anode materials, then they can achieve standard charging rates, but they are prone to lithium metallization and dendrite growth which compromise safety
Solution Approach 1:
The patent introduces a buffering zone comprising electron-donating groups (such as lithium borates/phosphates and polymer coatings) as an intermediary layer between the electrolyte and the anode active material particles. This intermediary buffering zone partially masks the positive charge of lithium ions, enabling them to move into the anode material for lithiation while preventing direct contact that would cause metallization and dendrite growth, thus resolving the contradiction between safety and charging rate.
Solution Approach 2:
The patent changes the charge state parameter of lithium ions by introducing electron-donating groups in the buffering zone that partially mask the positive charge of lithium ions, transforming them into partly masked lithium ions. This parameter change allows lithium ions to be incorporated into the anode material without causing metallization, enabling fast charging while maintaining safety.
2Productivity
If lithium ion batteries are designed for fast charging, then charging rates increase, but the probability of thermal runaway and cell breakdown increases
Solution Approach 1:
The patent applies beforehand cushioning by pre-configuring a buffering zone with electron-donating groups on the anode surface before lithium ion insertion begins. This buffering zone acts as a protective cushion that partially masks lithium ion charges and prevents direct metallization reactions, allowing fast charging to proceed without triggering thermal runaway or cell breakdown, thus enabling high charging rates while preventing harmful thermal effects.
3Speed
If lithium ions are allowed to accumulate on the anode surface, then charging speed increases, but dendrite growth occurs leading to battery failure
Solution Approach 1:
The buffering zone with electron-donating groups serves as an intermediary that prevents direct accumulation of fully charged lithium ions on the anode surface. Instead, it facilitates the formation of partly masked lithium ions that can be smoothly incorporated into the anode material, eliminating the conditions for dendrite growth while maintaining fast charging capability.
Solution Approach 2:
The patent changes the charge parameter of lithium ions from fully positive (Li+) to partly masked (Liδ+), preventing the accumulation condition that leads to dendrite formation. This parameter transformation allows high charging speeds without compromising battery stability or causing dendrite growth.
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 significantly reduces the probability of lithium metallization and dendrite growth, improving the safety and performance of lithium ion batteries by allowing for high charging and discharging rates while maintaining mechanical stability and preventing thermal runaway.
Implementation Method 1
the buffering zone comprises a plurality of electron donating groups interspaced between non-electron donating groups at a ratio of at least 1:2
Implementation Method 2
enable the partly masked lithium ions to move into an inner zone of the anode active material particles for lithiation therein
Implementation Method 3
partly mask a positive charge of the received lithium ions
Implementation Method 4
preventing thermal runaway
Data Source
AI summary
Improved anodes and cells are provided, which enable fast charging rates with enhanced safety due to much reduced probability of metallization of lithium on the anode, preventing dendrite growth and related risks of fire or explosion. Anodes and/or electrolytes have buffering zones for partly reducing and gradually introducing lithium ions into the anode for lithiation, to prevent lithium ion accumulation at the anode electrolyte interface and consequent metallization and dendrite growth. Various anode active materials and combinations, modifications through nanoparticles and a range of coatings which implement the improved anodes are provided.