Nanoparticle Polymer Dielectrics for High-Voltage Capacitors
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Solution Overview
Problem
Existing capacitors face challenges in achieving high energy density storage at high voltages while maintaining reliability, especially in environments with high ionizing radiation and requiring flexibility and robustness, as conventional dielectric materials tend to degrade and lose functionality.
Innovation Solution
A dielectric material comprising a polymer with nanoscale particles, specifically titanium dioxide, is developed, where the particles are homogeneously dispersed and have a diameter below the de Broglie wavelength of electrons, enhancing permittivity and radiation resistance, allowing for high energy density storage and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dielectric materials (polymers, ceramics) are used in capacitors, then the capacitor can be manufactured with standard materials, but the energy density storage capability is limited and reliability deteriorates in high voltage and radiation environments
Solution Approach 1:
The patent uses a composite dielectric material consisting of polymer matrix combined with nanoscale particles (titanium dioxide, barium titanate, or strontium titanate) with diameters below the de Broglie wavelength of electrons. This composite structure achieves both high energy density storage (exceeding 1 Joule per cubic centimeter) and improved reliability in radiation environments, resolving the contradiction between energy density and reliability.
2Reliability
If the particle diameter is reduced to nanoscale below de Broglie wavelength, then the permittivity and radiation resistance are enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise parameter ranges for the nanoscale particles, particularly the diameter being below the de Broglie wavelength of electrons (less than approximately 0.0037 nanometers at typical operating fields), and relative permittivity between 100-1000. These parameter specifications enable enhanced radiation resistance and permittivity while providing clear manufacturing targets for achieving the desired performance.
3Quantity of substance
If high voltage is applied to increase energy storage, then the energy density increases, but the dielectric breakdown risk increases
Solution Approach 1:
The patent incorporates nanoscale high permittivity particles distributed throughout the polymer matrix to create local regions of enhanced electrical properties. These localized high permittivity zones increase the overall energy storage capacity while the nanoscale dimensions and specific material selection (titanium dioxide, barium titanate, strontium titanate) provide localized protection against dielectric breakdown, enabling high voltage operation with improved reliability.
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 solution enables capacitors to store extremely high energy densities at high voltages, maintain reliability in radiation environments, and provide flexibility, suitable for applications like satellites and medical devices, with potential for fail-safe operation and rapid charge discharge.
Implementation Method 1
the diameter of said particles being in the nanometre range, characterised in that said particles are homogenously dispersed within the polymer, and the diameter of each of the particles is below the de Broglie wavelength of the electrons in the polymer
Implementation Method 2
The capability of the dielectric to store charge is measured in terms of its relative permittivity, that being the ability of a material to align along a field which promotes additional capability for storage of electrical energy
Implementation Method 3
This phenomenon is commonly described as Debye Dispersion, and can be described in the non-ideal case by the Havriliak and Negami semi-empirical relationship for a single isolated relaxation response
Implementation Method 4
As the field is established, the dipolar molecules move to align themselves along and against the field lines, and in so doing they increase the energy storage capacity of the material
Implementation Method 5
a further disadvantage to using polymers is that in many applications a capacitor might need to work in an environment of high ionising radiation, and few polymers retain their capability to function in such environments
Data Source
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Figure 4
AI summary
A dielectric material (14) for a capacitor comprising a first material and a second material, the first material being a polymer and the second material comprising particles. The particles are dispersed within the polymer, and are selected to have a relative permittivity higher than that of the polymer, characterised in that the diameter of the particles is in the nanometer range and the particles are geometrically controlled to a predermined shape.