Hybrid Capacitor Electrolyte and 3D Network Anode for Energy Density
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Solution Overview
Problem
Hybrid capacitors face a trade-off between high energy density and low electrical conductivity due to the use of metal compound particles that occlude and release lithium ions, often requiring significant amounts of carbon as a conductive additive, which can reduce energy density.
Innovation Solution
Employing metal compound particles with a three-dimensional network structure as the negative electrode active material, combined with a lithium salt electrolyte concentration of 1.6 M or more, and a solvent mixture of cyclic and chain carbonate esters, which reduces the need for carbon additives and enhances electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If metal compound particles that can occlude and release lithium ions are used as negative electrode active material, then energy density is improved, but electrical conductivity deteriorates
Solution Approach 1:
The patent uses metal compound particles (such as lithium titanate) as the negative electrode active material, which forms a composite structure that provides both high energy density through lithium ion occlusion/release capability and adequate electrical conductivity through the inherent properties of the metal compound and its network structure
Solution Approach 2:
The patent changes the concentration parameter of the electrolyte by using a lithium salt with a molar concentration of 1.6 M or more, which improves the electrical conductivity of the electrolytic solution and compensates for the low conductivity of the metal compound particles, thereby maintaining high energy density without requiring excessive carbon additives
2Reliability
If carbon is combined with metal compound particles to improve electrical conductivity, then electrical conductivity is improved, but energy density is reduced
Solution Approach 1:
The patent adjusts the electrolyte concentration parameter to 1.6 M or higher, which significantly improves the electrical conductivity of the electrolytic solution. This parameter change allows the system to achieve adequate conductivity without adding excessive carbon to the negative electrode, thereby preserving energy density
Solution Approach 2:
The patent uses the electrolyte as an intermediary medium to improve electrical conductivity. By using a lithium salt with high molar concentration (1.6 M or more), the electrolyte provides sufficient ionic conductivity to compensate for the low electronic conductivity of metal compound particles, eliminating the need for large amounts of carbon additives that would reduce energy density
3Reliability
If lithium salt concentration is increased to 1.6 M or more, then cycle characteristics are improved, but internal resistance increases
Solution Approach 1:
The patent optimizes the lithium salt concentration parameter to 1.6 M or more, which forms a stable solid electrolyte interface (SEI) layer that improves cycle characteristics. The high concentration provides sufficient lithium ions for continuous SEI formation and maintenance, ensuring long-term stability while the metal compound particles maintain low internal resistance through their inherent conductivity and network structure
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 increases energy density while improving cycle characteristics and discharging rate performance, reducing internal resistance and maintaining high conductivity without the need for excessive carbon, thus achieving a balance between energy storage and conductivity.
Implementation Method 1
metal compound particles which can occlude and release lithium ions
Implementation Method 2
The electrolytic solution includes a lithium salt with a molar concentration of 1.6 M or more as an electrolyte
Implementation Method 3
a positive electrode including a polarizable electrode having an electrical double-layer capacitance
Data Source
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AI summary
A hybrid capacitor with further increased energy density, and a manufacturing method thereof are provided. This hybrid capacitor is configured from a positive electrode which is a polarizable electrode that has double-layer capacitance, and a negative electrode which has a negative electrode active material which can occlude and release lithium ions and which is formed from metal compound particles having a three-dimensional network structure, wherein, as an electrolyte, the electrolytic solution contains lithium salts in a molar concentration greater than or equal to 1.6M.