Hybrid Metal Electrode Protective Layer for Battery Stability
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Solution Overview
Problem
Rechargeable batteries based on metal anodes, such as lithium, sodium, and aluminum, face instability issues due to chemical and physical interactions with electrolytes, leading to dendrite formation, internal shorts, and reduced Coulombic efficiency, limiting their commercial viability.
Innovation Solution
A hybrid electrode with an electrochemically active metal or metal salt protective layer is formed on the metal electrode through ion-exchange reactions, allowing for conformal contact and accommodating volume changes, thereby suppressing dendrite formation and enhancing ion transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is formed on the metal electrode to prevent chemical instability and dendrite formation, then reliability and safety improve, but ion transport resistance increases and Coulombic efficiency deteriorates
Solution Approach 1:
The patent applies the intermediary principle by introducing a thin aluminum oxide layer as a mediating protective coating between the reactive metal anode and the electrolyte. This intermediary layer prevents direct harmful chemical reactions while maintaining sufficient ion transport, thus improving reliability without excessively compromising Coulombic efficiency. The aluminum oxide layer acts as a controlled barrier that mediates the interaction between the metal electrode and electrolyte.
Solution Approach 2:
The patent employs parameter changes by precisely controlling the thickness and composition of the protective layer to optimize the balance between protection and ion transport. By adjusting parameters such as layer thickness, composition ratios, and formation conditions, the patent achieves a protective layer that provides adequate chemical stability while minimizing resistance to ion transport, thereby improving reliability without excessive energy loss.
2Stability of the object's composition
If the electrolyte composition is optimized to reduce dendrite formation, then morphology stability improves, but ion conductivity decreases and charge-discharge rate slows
Solution Approach 1:
The patent applies local quality by creating a protective layer with specific local properties on the metal electrode surface. The aluminum oxide layer provides localized protection at the electrode-electrolyte interface, ensuring uniform ion distribution and stable deposition morphology in critical areas without affecting the bulk electrolyte composition, thus maintaining fast charge-discharge rates while improving morphology stability.
Solution Approach 2:
The patent uses composite materials by combining the metal electrode with an aluminum oxide protective layer to create a composite structure. This composite electrode maintains the high conductivity and reactivity of the metal while incorporating the protective and morphology-stabilizing properties of aluminum oxide, enabling both stable deposition and fast ion transport.
3Quantity of substance
If alloying reactions are used to store lithium in high-energy metallic anodes, then specific capacity increases, but volume change destroys the SEI and causes chemical instability
Solution Approach 1:
The patent applies beforehand cushioning by pre-forming a robust aluminum oxide protective layer on the metal anode before lithium alloying reactions occur. This pre-formed protective layer acts as a cushion that accommodates volume changes during alloying reactions, preventing SEI destruction and maintaining chemical stability while allowing the high specific capacity of metallic anodes to be realized.
Solution Approach 2:
The patent uses flexible shells and thin films by employing a thin aluminum oxide protective layer that can flexibly accommodate volume changes during lithium alloying reactions. This thin film maintains conformal contact with the expanding and contracting metal anode, providing continuous protection against electrolyte decomposition and SEI instability while allowing the high capacity alloying reactions to proceed.
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 hybrid electrode enables stable, high-capacity, dendrite-free long-term cycling and improved energy density by maintaining mechanical and electrochemical stability, reducing interfacial impedance, and facilitating fast ion transport across the electrolyte-metal interface.
Implementation Method 1
A hybrid electrode with an electrochemically active metal or metal salt protective layer is formed on the metal electrode through ion-exchange reactions
Implementation Method 2
facilitating fast ion transport across the electrolyte-metal interface
Data Source
AI summary
Hybrid electrodes for batteries are disclosed having a protective electrochemically active layer on a metal layer. Other hybrid electrodes include a silicon salt on a metal electrode. The protective layer can be formed directly from the reaction between the metal electrode and a metal salt in a pre-treatment solution and/or from a reaction of the metal salt added in an electrolyte so that the protective layer can be formed in situ during battery formation cycles.