Semi-Solid Cathode Composition for Thick High-Rate Batteries
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Solution Overview
Problem
Conventional battery manufacturing methods result in electrodes with limited thickness, lower capacity, lower energy density, and higher inactive component ratios, making it difficult to produce batteries with both high rate capability and high charge capacity, and are costly and complex to manufacture.
Innovation Solution
The development of semi-solid electrodes with a suspension of 35% to 75% active material and 0.5% to 8% conductive material in a non-aqueous liquid electrolyte, allowing for thicker electrodes (250 μm to 2,000 μm) with reduced tortuosity and increased electronic conductivity, eliminating the need for binders and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional solid electrode methods are used, then manufacturing is simplified, but electrode thickness is limited to less than 100 μm resulting in lower capacity and energy density
Solution Approach 1:
The patent changes the physical state parameter of the electrode from solid to semi-solid, enabling thicker electrodes (250-2000 μm) to be manufactured using simpler infiltration processes rather than complex coating and drying methods required for solid electrodes
Solution Approach 2:
The patent uses liquid electrolyte infiltration (hydraulic principle) to impregnate the semi-solid electrode structure, allowing thick electrodes to be formed without complex manufacturing equipment by simply infiltrating the liquid electrolyte into the porous structure
2Reliability
If binder materials are added to solid electrodes, then electrode structural stability is improved, but tortuosity increases and ionic conductivity decreases
Solution Approach 1:
The patent extracts and eliminates binder materials from the electrode formulation, using semi-solid active material particles suspended in liquid electrolyte that self-assemble into stable structures without requiring additional binding agents, thereby reducing tortuosity and improving ionic conductivity
Solution Approach 2:
The patent creates a composite semi-solid electrode structure where active material particles are suspended in liquid electrolyte, forming a stable composite that provides both structural integrity and high ionic conductivity without binders
3Quantity of substance
If electrode thickness is increased to improve capacity, then charge capacity increases, but rate capability decreases due to higher inactive component ratios
Solution Approach 1:
The patent changes the electrode from solid to semi-solid state, enabling thick electrodes with high active material content (35-75% by volume) to achieve both high capacity and high rate capability by eliminating binder-induced tortuosity and improving electrolyte access to active material particles
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 batteries with superior rate capability and charge capacity, reducing the volume and cost of inactive components, and increasing energy density while simplifying the manufacturing process.
Implementation Method 1
a suspension of about 35% to about 75% by volume of an active material and about 0.5% to about 8% by volume of a conductive material in a non-aqueous liquid electrolyte
Data Source
AI summary
Embodiments described herein relate generally to electrochemical cells having high rate capability, and more particularly to devices, systems and methods of producing high capacity and high rate capability batteries having relatively thick semi-solid electrodes. In some embodiments, an electrochemical cells includes an anode and a semi-solid cathode. The semi-solid cathode includes a suspension of an active material of about 35% to about 75% by volume of an active material and about 0.5% to about 8% by volume of a conductive material in a non-aqueous liquid electrolyte. An ion-permeable membrane is disposed between the anode and the semi-solid cathode. The semi-solid cathode has a thickness of about 250 μm to about 2,000 μm, and the electrochemical cell has an area specific capacity of at least about 7 mAh/cm2 at a C-rate of C/4. In some embodiments, the semi-solid cathode slurry has a mixing index of at least about 0.9.