Dry Electrode Films With Electrolyte Salt for Solid-State Energy Storage
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Solution Overview
Problem
Existing energy storage devices face challenges in achieving improved electrical performance, reduced equivalent series resistance, increased power density, and energy density, while also requiring safer and less costly fabrication processes, particularly in solid-state lithium ion capacitors and batteries.
Innovation Solution
The development of dry electrode films comprising a dry active material, dry binder, and dry electrolyte salt, which are free-standing and solvent-free, allowing for controlled electrode film density and porosity through calendering processes, and optionally incorporating a foam or solid polymer electrolyte film, enabling pre-lithiation and solid-state operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wet electrode fabrication processes are used, then electrode films can be formed with adequate flexibility and adhesion, but the process requires flammable solvents which create safety hazards and increases manufacturing costs
Solution Approach 1:
The patent removes the solvent component from the electrode fabrication process entirely, transitioning from wet to dry processing. This extraction of the flammable solvent eliminates the safety hazard while maintaining the ability to form cohesive electrode films through alternative binding mechanisms.
Solution Approach 2:
The invention changes the physical state parameter of the electrode components from wet/slurry form to dry powder form. This parameter change eliminates the need for flammable solvents while requiring modified fabrication parameters such as higher compression pressures and controlled calendering temperatures to achieve proper film formation.
2Reliability
If dry electrode films are used without electrolyte salt, then the fabrication process is simpler and safer, but the electrical performance and ionic conductivity are insufficient
Solution Approach 1:
The patent merges the electrolyte salt directly into the electrode film matrix during fabrication, creating a composite structure where the electrolyte is distributed throughout the electrode. This integration ensures adequate ionic conductivity pathways while maintaining a relatively simple single-step fabrication process.
Solution Approach 2:
The invention creates a composite electrode material combining active material, binder, and electrolyte salt in a dry powder mixture. This composite approach provides both the electrical functionality of the active material and the ionic conductivity of the electrolyte within a single integrated structure.
3Quantity of substance
If electrode film thickness is increased to improve energy density, then more active material is stored, but the equivalent series resistance increases and cycling performance deteriorates
Solution Approach 1:
The patent incorporates porous structures within the electrode film that provide extensive internal surface area and interconnected pathways. This porosity allows increased active material loading for higher energy density while maintaining short ionic and electronic transport paths that prevent excessive resistance and ensure good cycling performance.
Solution Approach 2:
The invention transitions from planar, two-dimensional electrode structures to three-dimensional porous architectures. This dimensional change enables significantly increased active material volume within the same footprint while maintaining efficient transport pathways through the vertical and lateral pore networks.
4Power
If equivalent series resistance is reduced to improve power density, then faster charge-discharge rates are achieved, but the electrode formulation becomes more complex
Solution Approach 1:
The patent employs spherical or near-spherical active material particles instead of irregular shapes. This geometric optimization provides uniform packing, maximizes surface area for electrochemical reactions, and creates consistent current distribution throughout the electrode, thereby reducing equivalent series resistance while maintaining a relatively straightforward formulation approach.
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 solution results in energy storage devices with enhanced electrical and mechanical performance, higher electrode film densities, increased thickness, and safer operation without flammable solvents, reducing manufacturing costs and minimizing the risk of fires or explosions.
Implementation Method 1
controlled electrode film density and porosity through calendering processes
Implementation Method 2
a dry electrolyte salt... enabling pre-lithiation and solid-state operation
Data Source
AI summary
An energy storage device can include a cathode, an anode, and a separator between the cathode and the anode. At least one of the electrodes can include an electrode film prepared by a dry process. The electrode film, the electrode and/or the separator can comprise a salt, improved porosity, increased density, be prelithiated, and/or a foam. An energy storage device can include a dry composite solid polymer electrolyte (SPE) film. Processes and apparatuses used for fabricating the composite solid polymer electrolyte film, electrode and/or electrode film are also described.