Ionic Liquid SEI Transplantation for Aqueous Lithium Anodes
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Solution Overview
Problem
Current lithium battery technologies face challenges with water reactivity, as lithium metal reacts spontaneously with water, and common organic electrolytes fail when water is present, leading to cell failure and the lack of a stable solid-electrolyte interphase (SEI) for lithium or lithium-ion anodes in aqueous environments.
Innovation Solution
The method involves forming a solid-electrolyte interphase (SEI) on lithium or lithium-ion electrodes using a library of SEI formation electrolytes containing lithium salts and ionic liquids, followed by multiple charge/discharge cycles to create protected anodes that can withstand wet electrolytes with water concentrations above 50 ppm, optimizing the Artificial SEI Transplantation (AST) system by selecting the most effective electrolyte based on measured electrochemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If lithium metal or lithium-ion anode is used in the presence of water, then the battery can operate in aqueous environments, but the anode reacts spontaneously with water causing cell failure
Solution Approach 1:
The patent applies preliminary action by forming a protective solid-electrolyte interphase (SEI) layer on the lithium or lithium-ion anode surface before the anode is exposed to water. This is achieved by performing multiple charge/discharge cycles in a first cell with a non-aqueous electrolyte containing ionic liquids, which pre-forms a stable SEI layer that subsequently protects the anode during operation in wet electrolyte environments
Solution Approach 2:
The patent uses an intermediary approach by introducing a mediator substance (ionic liquid-containing electrolyte) that forms a protective interface between the reactive lithium anode and the aqueous environment. The SEI layer formed by ionic liquids acts as an intermediary barrier that allows ion transport while preventing direct water-anode contact
2Ease of operation
If common organic electrolytes are used, then the battery can function in standard conditions, but the electrolytes fail when water is present
Solution Approach 1:
The patent applies parameter changes by modifying the electrolyte composition to include specific ionic liquids with particular chemical properties. The ionic liquids contain functional groups that enable them to form stable SEI layers even in the presence of water, changing the chemical parameters of the electrolyte to achieve water tolerance while maintaining operational functionality
3Reliability
If SEI is formed to protect the anode, then the anode stability improves, but the SEI may passivate the electrode and diminish conductivity
Solution Approach 1:
The patent applies local quality by creating an SEI layer with spatially varying properties. The SEI formed by ionic liquids has different compositions and structures at different locations and depths, with the outer layers being more protective and inner layers maintaining higher ion conductivity, thus achieving both protection and conductivity through localized property differentiation
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
This approach enables the creation of electrochemically stable protected anodes that maintain conductivity and stability in the presence of water, allowing for the use of lithium or lithium-ion cells with wet electrolytes, significantly improving their performance and longevity.
Implementation Method 1
forming a solid-electrolyte interphase (SEI) on the lithium or lithium-ion electrode by performing multiple charge/discharge cycles on the electrode in a cell having the SEI formation electrolyte
Implementation Method 2
forming a solid-electrolyte interphase (SEI) on the lithium or lithium-ion electrode by performing multiple charge/discharge cycles
Data Source
AI summary
An anode for a lithium or lithium-ion cell, protected with an SEI by pre-treatment in an SEI-formation cell, is stable for cell cycling even in the presence of substantial water in the cell electrolyte. A method for making the protected anode includes forming an SEI on a lithium or lithium-ion electrode by performing multiple charge/discharge cycles on the electrode in a first cell having an SEI formation electrolyte to produce the protected anode. The SEI formation electrolyte includes an ionic liquid having at least one of eight organic cations.