LiSICon Membrane Crossflow for Stable LiOH and Hydrogen Production
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Solution Overview
Problem
Existing processes for recovering lithium from spent lithium-ion batteries are uneconomical and inefficient due to the high reactivity of lithium, short service life of LiSICon membranes, and impurities that damage the membranes, making it difficult to operate on an industrial scale while maintaining high purity and energy efficiency.
Innovation Solution
A process using a flat-sheet electrochemical cell with a LiSICon membrane, operating at high crossflow velocities and continuous flow conditions, to separate lithium ions from impurities, and produce lithium hydroxide and hydrogen efficiently, utilizing inorganic materials like LATP, LAGP, or LAGTSP for the membrane, and maintaining laminar flow in the catholyte compartment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LiSICon membranes are used to separate lithium ions from impurities, then lithium recovery efficiency is improved, but membrane service life is reduced due to impurity damage
Solution Approach 1:
The process divides the lithium recovery operation into multiple electrochemical cells arranged in series, where each cell handles a portion of the feed stream. This segmentation allows the system to process large volumes while maintaining manageable impurity loads per cell, reducing cumulative damage to individual membranes and extending their service life while preserving overall productivity.
Solution Approach 2:
The patent operates at controlled current densities and flow rates to optimize the balance between lithium recovery efficiency and membrane durability. By adjusting these operational parameters, the system maximizes lithium extraction while minimizing the rate of impurity accumulation on membrane surfaces, thereby extending membrane service life without sacrificing productivity.
2Productivity
If conventional electrolysis is used to produce lithium hydroxide, then production capacity is achieved, but energy consumption is excessive
Solution Approach 1:
The patent combines lithium ion separation through the LiSICon membrane with water electrolysis in a single integrated electrochemical cell. This merging allows simultaneous lithium recovery and hydrogen production, achieving high production capacity while utilizing the electrical energy more efficiently for dual purposes rather than separate processes.
Solution Approach 2:
The process maintains continuous operation with constant feed flow and electrical current through the electrochemical cells, ensuring uninterrupted lithium hydroxide production. This continuity eliminates startup/shutdown energy losses and maintains optimal efficiency throughout operation, achieving high production capacity with reduced specific energy consumption.
3Productivity
If high current density is applied to increase production rate, then productivity is improved, but membrane stability deteriorates due to impurity accumulation
Solution Approach 1:
By distributing the total current across multiple electrochemical cells in series, each cell operates at moderate current density that maintains membrane stability. The segmented arrangement allows the system to achieve high overall production rate through increased throughput rather than excessive current density in single cells, preventing impurity accumulation and maintaining membrane stability.
Solution Approach 2:
The system monitors operational parameters to maintain current density within ranges that preserve membrane stability while achieving target production rates. This feedback control ensures that productivity improvements do not compromise membrane integrity by adjusting operating conditions in real-time.
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 process achieves high membrane stability and efficiency, allowing the recovery of lithium hydroxide with high purity and reduced energy consumption, even in the presence of impurities, thereby making it economically viable for industrial use.
Implementation Method 1
the flat-sheet membrane comprises an inorganic material that possesses conductivity for Li ions and that is electrically insulating
Implementation Method 2
electrochemical production of hydrogen and lithium hydroxide
Data Source
AI summary
The problem addressed by the present invention is that of specifying a process for the electrochemical production of LiOH from Li+-containing water with the aid of an electrochemical cell with LiSICon membrane that can be operated economically on an industrial scale too. In particular, the process should have good energy efficiency and achieve a high membrane lifetime even when the employed feed contains impurities that are harmful to LiSICon materials. The problem is solved by the flow conditions in the anodic compartment of the electrochemical cell being established such that the anolyte flows along the membrane with a certain minimum crossflow velocity.