Hybrid Active Material Structures for Battery Electrodes
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Solution Overview
Problem
Rechargeable batteries face a tradeoff between capacity and cycle life, with layered active materials offering long cycle lives but limited capacity, while non-layered materials have higher capacity but poor durability due to structural changes during ion insertion and extraction.
Innovation Solution
Hybrid active material structures are formed by combining different layered active materials in a specific arrangement, where one material forms a stable solid electrolyte interface layer and another has higher capacity, enhancing both capacity and cycle life by integrating them into a single structure before forming an electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If non-layered active materials are used, then initial capacity is improved, but cycle life deteriorates due to structural changes during ion insertion and extraction
Solution Approach 1:
The patent combines non-layered active materials with layered active materials to form a composite structure. The non-layered material (e.g., silicon, tin) provides high capacity while the layered material (e.g., graphite, MoS2) provides structural stability. This composite approach allows the system to achieve both high initial capacity and long cycle life by leveraging the complementary properties of each material type.
Solution Approach 2:
The patent employs layered active materials as protective shells or coatings around non-layered active material particles. This shell structure accommodates the volume expansion and contraction of the non-layered material during ion insertion/extraction, preventing structural degradation while maintaining high capacity. The layered shell acts as a flexible protective barrier that maintains structural integrity over many cycles.
2Reliability
If layered active materials are used, then cycle life is improved, but initial capacity deteriorates due to limited ion insertion sites
Solution Approach 1:
The patent creates composite structures where high-capacity non-layered materials are combined with stable layered materials. The non-layered material contributes high capacity while the layered material contributes structural stability and long cycle life. This composite approach overcomes the capacity limitation of pure layered materials while maintaining their durability advantages.
Solution Approach 2:
The patent structures the electrode with non-layered active material particles nested within or coated by layered active material shells. This nested configuration allows the high-capacity non-layered material to be protected and supported by the stable layered structure, enabling the system to achieve both high capacity and long cycle life simultaneously.
3Quantity of substance
If high-capacity non-layered materials are used, then capacity is improved, but structural stability deteriorates during ion insertion and extraction
Solution Approach 1:
The patent uses layered active materials to form flexible shells around non-layered active material particles. These shells accommodate the significant volume changes that occur during ion insertion and extraction in high-capacity materials like silicon or tin. The layered shell structure maintains structural stability while allowing the inner high-capacity material to undergo necessary volume expansion and contraction.
Solution Approach 2:
The patent creates composite structures where non-layered high-capacity materials are combined with layered stable materials. The layered component provides structural stability and prevents degradation during cycling, while the non-layered component provides high capacity. This composite approach resolves the contradiction between capacity and structural stability.
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 allows for synergistic effects, utilizing the high capacity and conductivity of one material while stabilizing it with a layer that forms a stable interface, thereby improving the overall performance of electrochemical cells by extending cycle life and maintaining high capacity.
Implementation Method 1
a layered active material, which forms a stable solid electrolyte interface (SEI) layer, may be form an outer shell of a hybrid active material structure and interface with electrolyte
Implementation Method 2
Layered active materials allow insertion and extractions of ions between adjacent layers of these materials, which results in minimal impact to the host structure of each layer
Implementation Method 3
The one or more first substructures interface and are attached to the one or more second substructures
Data Source
AI summary
Provided are hybrid active material structures for use in electrodes of electrochemical cells and methods of forming these structures. A hybrid active material structure comprises at least one first substructure and at least one second substructures, each comprising a different layered active material and interfacing each other. Combining multiple layered active materials into the same structure and arranging these materials in specific ways allow achieving synergetic effects of their desirable characteristics. For example, a layered active material, which forms a stable solid electrolyte interface (SEI) layer, may be form an outer shell of a hybrid active material structure and interface with electrolyte. This shell may surround another layered active material, which has a higher capacity but would otherwise forma a less stable SEI layer. Furthermore, multiple layered active materials may be arranged into a stack, in which one of these materials may operate as an ionic and/or electronic conductor.