Composite Electrode Whisker Coating for High Capacitance
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Solution Overview
Problem
Conventional electrochemical capacitors and lithium-ion batteries face challenges in achieving high capacitance and balancing capacitance with conductivity, with existing electrodes either relying solely on electric double layer capacitance or using single-composition whiskers that struggle to optimize performance.
Innovation Solution
A composite electrode is developed by forming a predetermined coating layer on whiskers or fibers made of metal or metal compounds, which are heat-treated and grown on a substrate, enhancing capacitance and responsiveness through improved conductivity and active material integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If oxide is deposited on activated carbon fibers to generate electrochemical capacitance, then electrochemical capacitance is achieved, but the activated carbon fibers only provide electric double layer capacitance and sufficient capacitance is not obtained
Solution Approach 1:
The invention uses composite materials by combining metal whiskers (such as zinc oxide, tungsten oxide, or titanium oxide) with coating layers containing active materials (such as manganese oxide, nickel oxide, cobalt oxide, or titanium oxide). This composite structure allows the electrode to achieve high capacitance through the synergistic effects of the conductive metal whiskers and the capacitive active material coating, while maintaining structural integrity and electrical conductivity.
Solution Approach 2:
The invention applies local quality by forming coating layers containing active materials on specific portions of the metal whiskers. The coating layer is formed on at least a part of the surface of the needle-shaped columns, allowing different regions of the electrode to have different functions: the metal whiskers provide conductivity and structural support, while the coating layers provide electrochemical capacitance through redox reactions.
2Quantity of substance
If whiskers with a single composition are used to generate electrochemical capacitance, then electrochemical capacitance is achieved, but it is difficult to strike a balance between capacitance and conductivity
Solution Approach 1:
The invention employs composite materials with a two-component structure: metal whiskers (such as zinc oxide, tungsten oxide, or titanium oxide) that provide excellent electrical conductivity and structural framework, combined with coating layers containing active materials (such as manganese oxide, nickel oxide, cobalt oxide, or titanium oxide) that provide high electrochemical capacitance. This composite approach allows simultaneous optimization of both capacitance and conductivity, resolving the trade-off between these two critical properties.
Solution Approach 2:
The invention implements local quality by assigning different functional roles to different components of the composite structure. The metal whiskers are optimized for conductivity and structural support, while the coating layers are optimized for electrochemical capacitance through redox reactions. This functional differentiation allows each component to excel at its specific function, achieving overall balance between capacitance and conductivity.
3Reliability
If a substrate with tungsten oxide whiskers is used as an electrode for lithium-ion battery, then preferred performance is achieved, but there is room for improvement in further increase of capacitance
Solution Approach 1:
The invention uses composite materials by combining metal whiskers (such as zinc oxide, tungsten oxide, or titanium oxide) with coating layers containing active materials (such as manganese oxide, nickel oxide, cobalt oxide, or titanium oxide). This composite structure allows the electrode to achieve high capacitance through the synergistic effects of the conductive metal whiskers and the capacitive active material coating, while maintaining structural integrity and electrical conductivity.
Solution Approach 2:
The invention applies dimensionality change by adding a coating layer dimension to the existing metal whisker structure. The coating layer is formed on the surface of the needle-shaped columns, creating a hierarchical structure that increases the effective surface area and provides additional redox reaction sites, thereby increasing capacitance without compromising the underlying whisker framework.
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 composite electrode achieves high capacitance and excellent responsiveness by leveraging the conductivity of whiskers or fibers and the active material coating, allowing for stable performance and efficient charge/discharge cycles.
Implementation Method 1
performing heat treatment for a raw material or a precursor of the substrate containing a constituent metal of the whisker or the fiber in an oxidizing atmosphere, and forming the whisker or the fiber on the substrate
Implementation Method 2
performing heat treatment for a raw material or a precursor of the substrate containing a constituent metal of the whisker or the fiber in an oxidizing atmosphere
Implementation Method 3
generate electrochemical capacitance by depositing titanium oxide and the like on surfaces of activated carbon fibers
Implementation Method 4
generate the electrochemical capacitance by forming amorphous oxide whiskers
Implementation Method 5
an electricity storage device using the composite electrode for the electricity storage device, the electricity storage device including: the composite electrode for the electricity storage device; and an electrolyte
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3~4
AI summary
A composite electrode for an electricity storage device of the present invention includes: a substrate; a whisker or a fiber which is made of at least one of a metal and a metal compound and is formed on the substrate; and a coating layer which contains an active material and is formed on at least a part of a surface of the whisker or the fiber.