MXene-Coated Wool Yarn Supercapacitors for Flexible Energy Storage
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Solution Overview
Problem
Conventional energy storage devices, such as capacitors and batteries, are too rigid and bulky to be incorporated into clothing, necessitating the development of soft and flexible energy storage solutions.
Innovation Solution
The use of conductive protein-based yarns, specifically sheep wool yarns coated with Ti3C2Tx MXene flakes or conductive-polymer-coated MXene flakes, to create textile-based supercapacitors (TSCs) that are flexible and durable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional energy storage devices (capacitors and batteries) are used, then energy storage capacity is achieved, but the devices are too rigid and bulky to be incorporated into clothing
Solution Approach 1:
The patent applies this principle by replacing rigid capacitor and battery structures with flexible textile-based supercapacitor components. The electrodes are formed from conductive yarns woven into flexible fabric structures, eliminating the need for rigid housings and enabling integration into clothing while maintaining energy storage functionality.
Solution Approach 2:
The patent employs composite materials by combining conductive polymers with textile fibers to create conductive yarns. These composite yarns integrate the electrical conductivity needed for energy storage with the mechanical flexibility and softness required for wearable applications, resolving the contradiction between energy storage capacity and flexibility.
2Reliability
If MXene flakes are used to coat yarns for textile-based supercapacitors, then electrical conductivity and capacitance are improved, but the yarn becomes stiff and may break during knitting
Solution Approach 1:
The patent applies this principle by optimizing the size parameters of MXene flakes and controlling the coating thickness and distribution. By using smaller MXene flakes and achieving uniform thin coatings on the yarn surface, the electrical conductivity is enhanced while minimizing the stiffening effect that would compromise yarn flexibility and processability.
Solution Approach 2:
The patent implements local quality by ensuring MXene coating is distributed uniformly across the yarn surface rather than forming concentrated rigid patches. This localized, even coating approach maintains electrical conductivity throughout the yarn while preserving overall yarn flexibility and preventing stress concentration points that would lead to breakage.
3Quantity of substance
If MXene material is used for coating, then volumetric capacitance up to 1500 F/cm³ is achieved, but the material is susceptible to oxidation and degrades over time
Solution Approach 1:
The patent applies this principle by introducing protective intermediary layers or encapsulation structures that shield the MXene material from oxidative environments. These intermediary protective layers allow the MXene to maintain its high volumetric capacitance while preventing direct exposure to oxygen and moisture that would cause degradation.
Solution Approach 2:
The patent converts the harmful oxidation effect into a beneficial outcome by designing the supercapacitor system to utilize controlled oxidation products or by incorporating antioxidants that transform potential degradation pathways into stable, long-lasting structures that enhance overall device reliability while preserving MXene's high capacitance properties.
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 resulting TSCs demonstrate enhanced electrical performance, including specific linear capacitance greater than 0.15 mF/cm and specific areal capacitance greater than 180 mF/cm², while also offering improved oxidative stability and longevity compared to traditional MXene-coated fibers.
Implementation Method 1
coating yarns with conductive materials... MXene flakes act like a pigment and stiffen the yarn during the coating process
Implementation Method 2
a conductive polymer (e.g., polypyrrole (PPY) or polyaniline (PANI)) is polymerized in the presence of MXene flakes
Implementation Method 3
specific linear capacitance greater than 0.15 millifarad per centimeter (mF/cm)... specific areal capacitance greater than 180 millifarad per square centimeter (mF/cm2)
Implementation Method 4
the material is susceptible to oxidation, and upon oxidative degradation of the MXene flakes, titanium dioxide (TiO2) and carbon dioxide (CO2) are produced
Data Source
AI summary
Systems and methods are presented for fabricating conductive protein-based yarns to produce textile-based supercapacitors (TSCs). Conductive wool yarns are created by coating wool yarn with Ti3C2Tx MXene flakes, or by coating wool yarn in MXene@conductive-polymer composite material, such as MXene@polypyrrole (PPY) or MXene@polyaniline (PANI). In some examples, the conductive polymer (e.g., polypyrrole (PPY) or polyaniline (PANI)) is polymerized in the presence of MXene flakes to yield conductive-polymer-coated MXene flakes (MXene@conductive-polymer), and then this material is then used to coat wool yarn to yield a conductive protein-based yarn. MXene materials offer a high conductivity, but tend to oxidize quickly, while conductive polymers have a lower conductivity, but are more chemically stable and less likely to oxidize. As such, it is presently recognized that, by combining these materials, a chemically stable and highly conductive composite material is formed that can be used to coat yarns to make TSCs.