Semi-Solid Electrodes With High-Salt Electrolyte for Thick Cell Ion Transport
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Solution Overview
Problem
The production of electrochemical cells with conventional electrodes is limited by ion transport issues, particularly lithium ion depletion during fast charge or discharge, which restricts the thickness and performance of semi-solid electrodes.
Innovation Solution
The method involves creating high-viscosity semi-solid electrodes with a non-aqueous liquid electrolyte of high salt concentration, combined with active and conductive materials, and applying a carbon coating to enhance ion transport and contact with separators, allowing for thicker electrodes and improved rate capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electrode thickness is increased to improve capacity, then energy density is improved, but ion transport limitations worsen causing lithium ion depletion
Solution Approach 1:
The patent changes the physical and chemical parameters of the electrode by using a semi-solid slurry composition with high salt concentration electrolyte (at least 2,000 mol/m³), specific viscosity range (10-1,000 Pa·s), and controlled particle size distribution. These parameter changes enable the electrode to maintain good ion transport properties even at thicknesses of at least 150 μm, resolving the contradiction between increased capacity and ion transport limitations
Solution Approach 2:
The patent creates a composite semi-solid electrode structure combining active material particles, conductive material particles, and liquid electrolyte in a slurry formulation. This composite approach with specific material ratios and binding agents enables both high capacity and improved ion transport, allowing the electrode to achieve thicknesses that would normally cause lithium ion depletion
2Reliability
If semi-solid electrodes are made binderless to improve electroactive species movement, then ion transport is improved, but manufacturing complexity increases
Solution Approach 1:
The patent uses a slurry-based manufacturing approach with controlled viscosity (10-1,000 Pa·s) and salt concentration (at least 2,000 mol/m³) that allows the semi-solid electrode to be self-supporting without traditional binders. This parameter control enables binderless construction while maintaining structural integrity during manufacturing, resolving the contradiction between improved electroactive species movement and manufacturing complexity
Solution Approach 2:
The patent introduces a liquid electrolyte as an intermediary medium that provides both the liquid phase for ion transport and the binding function normally performed by solid binders. This intermediary approach enables binderless electrode construction while maintaining both structural integrity and excellent ion transport properties
3Power
If fast charge and discharge rates are increased to improve power output, then rate capability is improved, but lithium ion depletion worsens
Solution Approach 1:
The patent uses high salt concentration electrolyte (at least 2,000 mol/m³, preferably at least 3,000 mol/m³) and optimized viscosity (10-1,000 Pa·s) to enhance lithium ion availability and transport speed. These parameter changes enable the electrode to sustain fast charge and discharge rates (at least 1.5 C) without lithium ion depletion, resolving the contradiction between improved power output and ion depletion
Solution Approach 2:
The patent pre-saturates the electrode structure with high-concentration electrolyte during manufacturing, ensuring充足的 lithium ion supply is already in place before operation. This preliminary action of pre-loading the electrode with concentrated electrolyte enables the system to handle fast charge/discharge demands without experiencing ion depletion during operation
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 production of thicker, higher-capacity electrochemical cells with enhanced rate capabilities and energy density by reducing tortuosity and increasing electronic conductivity, while mitigating lithium ion depletion and internal impedance.
Implementation Method 1
improvement of ion transport can mitigate these issues
Implementation Method 2
combining an active material with a conductive material and a non-aqueous liquid electrolyte to form a semi-solid cathode
Implementation Method 3
coating the first surface of the separator with a carbon coating
Implementation Method 4
charging and discharging the electrochemical cell while the electrochemical cell is oriented such that the thickness of the cathode is in line with the direction of gravity
Data Source
AI summary
Embodiments described herein relate to electrode and electrochemical cell material recycling. Recycling electrode materials can save significant costs, both for quenching chemicals and for the costs of the materials themselves. Separation processes described herein include centrifuge separation, settler separation, flocculant separation, froth flotation, hydro cyclone, vibratory screening, air classification, and magnetic separation. In some embodiments, methods described herein can include any combination of froth flotation, air classification, and magnetic separation. In some embodiments, electrolyte can be separated from active and/or conductive materials via drying, subcritical or supercritical carbon dioxide extraction, solvent mass extraction (e.g., with non-aqueous or aqueous solvents), and/or freeze-drying. By applying these separation processes, high purity raw products can be isolated. These products can be re-used or sold to a third party. Processes described herein are scalable to large cell production facilities.