With the rapid advancement of technology, smart wearable devices are becoming increasingly ubiquitous, integral to our daily lives, sports activities, health monitoring, and even personal safety. However, achieving truly “body-integrated” intelligence hinges on solving the challenge of power supply: conventional batteries are bulky and rigid, making it difficult to incorporate them into soft textile materials; moreover, their lifespan, charge–discharge performance, and wash durability all present significant challenges.

Therefore, the development of lightweight, flexible, washable energy storage devices with superior performance has emerged as a critical breakthrough for advancing the smart wearable industry. Supercapacitors, with their high power density, long cycle life, and rapid charge–discharge capabilities, stand out as one of the most promising options. The ultimate goal of the industry is to directly integrate supercapacitors into textiles.

Today, we will introduce an exciting technological breakthrough: using aerosol jet printing (AJP) to directly “print” high-performance MXene materials onto fabrics, creating flexible, washable, and exceptionally performing micro-supercapacitors that are poised to revolutionize wearable electronics.

Working Principle

1. What are MXene materials?

MXenes are a class of two-dimensional materials composed of layered transition-metal carbides or nitrides, exhibiting exceptionally high electrical conductivity, rich surface chemical reactivity, and outstanding mechanical properties. These characteristics make MXenes an ideal electrode material for supercapacitors.

2. Aerosol Jet Printing (AJP)

Aerosol Jet Printing (AJP) is, in essence, a high-precision material deposition technique. Unlike conventional printing methods, AJP delivers micrometer-level resolution, offers flexible operation, and is compatible with a wide range of viscosities, making it particularly well-suited for the direct fabrication of electronic components on soft, irregular surfaces such as fabrics.

3. Technology Integration: Binder-Free MXene Ink

At the heart of this technology is the use of “pure, water-based MXene ink,” which is deposited layer by layer onto textile surfaces via aerosol jet printing (AJP) to form a continuous, uniform conductive coating. These MXene coatings exhibit exceptionally high conductivity and require no binders or additional metallic electrodes, thereby significantly simplifying device architecture and reducing the weight of the final product.

4. Energy Storage Mechanism

The resulting supercapacitor leverages MXene’s electric double-layer capacitance and surface redox reactions (pseudocapacitance) to achieve rapid charge–discharge kinetics and long cycle life for energy storage. Simply put, conductive “storage units” formed on the textile surface enable the storage and release of electrical energy, providing a portable power source.

Innovation Highlights

1. High-performance electrode

Ultra-high specific capacitance: up to 4.4 farads per square centimeter can be achieved per unit area, representing a substantial improvement over conventional flexible electrodes.

Wide voltage window: a operating range of –0.65 V to 0.2 V, which enhances energy density.

Outstanding cycle life: After 10,000 charge–discharge cycles, the capacity remains virtually unchanged, demonstrating exceptional stability.

Wash-resistant and durable: The electrodes maintain excellent performance even after up to 100 wash cycles, simulating real-world washing conditions.

2. Textiles as Direct Electrodes

By employing aerosol jet printing (AJP)—a maskless, high-precision jetting technique—electrode patterns can be directly “printed” onto a wide range of textile materials, including cotton and polyester.

Thin, uniform, and highly adhesive, with no adverse impact on the fabric’s hand or appearance.

3. Flexible and Customizable

Design diversified electrode structures—such as interleaved, parallel, or series configurations—to meet the requirements of various electronic devices.

No restrictions on shape or size—designs can be freely customized to suit a wide range of devices and apparel.

Application Prospects

1. Energy Supply in Smart Clothing

Directly sewn into sportswear, medical monitoring garments, military equipment, and more, creating an “on-body” energy storage solution.

It does not affect everyday wear and is easy to wash and maintain.

2. Wearable Medical Devices

Designed for smart wristbands and health-monitoring apparel, providing continuous and stable power supply.

The supercapacitor’s rapid charge–discharge characteristics make it well suited for the dynamic acquisition and storage of physiological data.

3. Smart Sports Equipment

Such as smart running shoes and yoga apparel, which both ensure adequate energy supply during exercise and provide exceptional comfort.

Enables wireless communication and power supply for sensors, enhancing the user experience.

4. Flexible Electronic Skin and Biomimetic Materials

Integration into robots, bionic gloves, and other applications will spearhead the future of flexible electronics.

Illustrated Guide

Figure 1. Characterization of additive-free aqueous Ti3C2Tx ink. a) Schematic illustration of the atomization and pneumatic focusing aerosol jet printing (AJP) process for Ti3C2Tx ink. b) TEM image of Ti3C2Tx flakes. c) Histogram of the size distribution of Ti3C2Tx flakes in the ink, determined by ImageJ analysis across multiple images (Figures S1 and S5, Supporting Information), followed by statistical analysis. d) TEM image after ultrasonic atomization in aerosol jet printing (AJP), showing wrinkled Ti3C2Tx flakes. e) Optical microscopy image of an interdigitated device (IDD) printed on cotton, demonstrating the high-resolution imaging capability of aerosol jet printing (AJP). f) Relationship between the resistance of a (1 × 6) mm² sample on cotton and the number of AJP deposition layers. The inset shows a strong linear correlation between mass loading and the number of printed layers (R² = 0.98896), confirming the consistency and precision of material deposition via aerosol jet printing (AJP). SEM images of Ti3C2Tx MXene deposited by aerosol jet printing (AJP) on g) cotton (C), h) polyester-cotton blend (PC), and i) polyester (PR). The blue dashed line indicates the boundary between the pristine fabric (left) and the printed Ti3C2Tx film (right). j) Close-up view of the cotton surface, highlighting individual Ti3C2Tx ink droplets on the fabric. k) XRD spectra comparing Ti3C2Tx MXene films with MXene-printed fabrics (MX@C, MX@PC, MX@PR). The spectra reveal characteristic MXene-related peaks as well as distinct fabric-specific peaks, underscoring successful integration and tailored material–fabric interactions; further details are provided in Figures S10–S14 (Supporting Information).

Figure 2. Electrochemical characteristics of MX@Fabric electrodes fabricated by aerosol jet printing (AJP). a) Cyclic voltammograms of the MX@C-10L electrode at scan rates of 5, 10, 11, 12, 13, 15, 16, 20, 30, 50, 100, 200, 300, 500, and 1000 mV s−1, demonstrating the pseudocapacitive behavior of Ti3C2Tx in sulfuric acid. b) Galvanostatic charge–discharge curves of the MX@C-10L electrode at current densities of 10, 20, 50, 100, 200, and 500 mA cm−2, exhibiting a symmetrical yet nonlinear profile. c) Comparative cyclic voltammograms of the MX@C-10L, MX@PC-10L, and MX@PR-10L electrodes at a scan rate of 5 mV s−1. d) Comparison of the rate capability of the MX@C-10L, MX@PC-10L, and MX@PR-10L electrodes, expressed in terms of areal capacitance. e) Rate performance of MX@C electrodes with 10, 20, 30, 50, and 100 printed layers. f) Comparative galvanostatic charge–discharge curves of MX@C electrodes with 10, 20, 30, 50, and 100 printed layers at a current density of 10 mA cm−2. g) Analysis of charge-storage kinetics via b-value evaluation for the MX@C-10L, MX@PC-10L, and MX@PR-10L electrodes. A dashed line with a slope of b = 1 indicates an ideal capacitive/pseudocapacitive charging mechanism and rapid ion diffusion. h) Cycling stability study of the MX@C-10L, MX@PC-10L, and MX@PR-10L electrodes, conducted through 10,000 long-cycle voltammetric tests at a scan rate of 100 mV s−1.

Figure 3. Wash durability study of the MX@C-10L-#W electrode (conducted in accordance with ISO 105-C06, Test A1M), using microscopic observation and electrochemical analysis. a–c) Optical microscopy (left) and scanning electron microscopy (right) images show, respectively, the as-received (0W), after 5 washes (5W), and after 60 washes (60W) samples, highlighting fabric integrity, MXene distribution, and microstructural changes as the number of washes increases. d) Cyclic voltammograms at a scan rate of 5 mV s−1 for different washing cycles, exhibiting distinct cathodic and anodic peaks. e) Rate-performance plot summarizing the capacitance variation over multiple washing cycles. f) Analysis of charge-storage kinetics at different washing stages based on the b value. The dashed line with a slope of b = 1 indicates an ideal capacitive/pseudocapacitive charging mechanism and rapid ion diffusion.

Figure 4. Aerosol jet-printed (AJP) Ti3C2Tx MX@C MSCs with an IDD electrode architecture. a) Cyclic voltammograms of the MX@C-30L MSC at scan rates of 2, 5, 10, 20, 30, and 50 mV s−1. b) Galvanostatic charge–discharge curves of the MX@C-30L MSC at current densities of 0.5, 1, 2, and 4 mA cm−2. c) Comparison of areal capacitance among printed MSCs reported in the literature [4, 23, 51, 55–65], with samples marked by * having been fabricated in this study; see Table S3 in the Supporting Information for details. d) Ragone plot comparing the reported printed MSCs [23, 51, 56, 57, 60, 64], with samples marked by * having been fabricated in this study; see Table S4 in the Supporting Information for details. e) Electrochemical performance of the MX@C MSC under bending at 0°, 45°, 90°, 135°, and 180° at a scan rate of 10 mV s−1. f) Retention of areal capacitance as a function of bending angle. g) Comparison of single-series, two-series (2S), and two-parallel (2P) MSC devices, as well as a four-series series-connected device used to power an LED bulb; see the figure caption.

Thanks to rapid technological advances, it is now possible to deeply integrate “electrification” into our everyday clothing. This groundbreaking innovation—using aerosol jet printing (AJP) to directly fabricate supercapacitors on textiles—offers a brand-new solution for the future of smart apparel. With its high performance, washability, lightweight design, and customizable features, it is poised to usher in a new era for the wearable electronics industry.

We believe that in the near future, each of us will be able to wear smart clothing that “generates its own energy,” eliminating concerns about insufficient battery capacity, inconvenient charging, and even damage from washing. Technology is making life more convenient and smarter, and this innovation is the key to unlocking the “smart wardrobe” of the future.