PVDF/PAN-based triboelectric nanogenerator for biomechanical energy harvesting and health monitoring applications Open Access

Recently, with the continuous advancement of technology and the increasingly perfect solutions, the digital transformation of various industries driven by the rapid development of the digital economy is accelerating comprehensively.^1,2 The application scenarios of IoT technology in fields such as intelligent manufacturing, smart homes, and smart transportation are becoming increasingly diverse and gradually maturing.³ In this context, the form and function of wearable smart devices are also continuously evolving, showing broad application prospects in multiple fields, especially in human health monitoring and personalized medicine. Wearable devices are gradually transforming from traditional motion tracking devices to intelligent systems with multi-parameter physiological monitoring capabilities.^4,5 By collecting and analyzing real-time physiological data such as heart rate, blood oxygen saturation, body temperature, and respiratory rate, these devices can provide users with accurate health assessments and risk predictions while supporting personalized health management. In addition, the importance of wearable devices in chronic disease management, postoperative rehabilitation monitoring, and remote healthcare is becoming increasingly prominent.⁶ The implementation of these functions not only optimizes the allocation of medical resources but also reduces users’ dependence on traditional medical institutions, providing the possibility for building a smart medical ecosystem. However, one of the core challenges facing the widespread adoption of wearable devices is how to provide them with a reliable and sustainable energy supply. Due to the fact that these devices often require continuous operation and are strictly limited in size and weight, it is crucial to develop efficient, lightweight, and durable energy solutions suitable for power levels ranging from microwatts to milliwatts.^7,8 At present, research on this issue is focusing on energy harvesting and storage technology, which collects mechanical energy, thermal energy, or light energy from the environment to power devices. This energy self-supply capability will effectively improve the endurance of wearable devices and significantly enhance their reliability in practical applications.

Triboelectric nanogenerators (TENGs), as an emerging energy harvesting technology, offer an innovative and efficient solution for converting low-frequency mechanical energy into electrical energy through the coupling of triboelectric and electrostatic induction effects.^9–23 TENGs exhibit several advantages, including a simple structure, low cost, high energy conversion efficiency, and strong adaptability.^24,25 They can be flexibly designed to harvest mechanical energy from physiological energy from the human body (e.g., respiratory movements, heartbeats, and blood pressure fluctuations).²⁶ In the field of human health monitoring, TENGs demonstrate significant potential, functioning not only as a sustainable energy source for wearable devices but also as passive sensors for real-time monitoring of physiological parameters such as respiratory rate, heartbeat patterns, and blood pressure. These capabilities provide novel solutions for personalized health management and chronic disease monitoring. Moreover, the integration of TENGs into wearable devices enables continuous physiological state monitoring, reduces dependence on external energy sources, and enhances the portability and reliability of these systems.^27–29 To further improve the power density and broaden the application scope of TENGs in complex environments, the development of advanced materials with high charge density, superior mechanical properties, and excellent biocompatibility is imperative. Flexible, lightweight, and biocompatible materials can enhance the adhesion between TENGs and human tissues, increase the sensitivity of signal acquisition, and improve the reliability of TENGs under high-humidity or challenging environmental conditions.³⁰ These advancements provide robust support for the widespread application of TENGs in health monitoring and medical equipment, paving the way for more efficient and reliable wearable healthcare technologies.^31,32 Polyvinylidene fluoride (PVDF) is widely recognized as an ideal material for TENGs due to its exceptional dielectric properties, flexibility, and piezoelectric characteristics.³³ As a semicrystalline polymer, PVDF exhibits a strong ability to gain electrons during triboelectric interactions, enhancing the surface charge density and overall energy conversion efficiency of TENGs. Its high mechanical strength and thermal stability ensure durability under repeated mechanical stress, making it suitable for long-term applications.^34,35 Furthermore, PVDF’s excellent processability allows for the fabrication of thin films and nanostructures, enabling versatile designs for various energy harvesting and sensing applications, including wearable devices and biomedical monitoring systems. Polyacrylonitrile (PAN) is a versatile polymer widely utilized in various applications due to its excellent mechanical properties, high thermal stability, and chemical resistance.³⁶ As a semicrystalline material, PAN exhibits strong intermolecular interactions, which contribute to its exceptional tensile strength and durability. PAN is often used as a precursor for carbon fiber production because of its high carbon yield and structural stability during thermal treatment. In the field of functional materials, PAN’s polar nitrile groups provide strong electron-accepting capabilities, making it an ideal candidate for enhancing the triboelectric performance of composite materials, such as PVDF/PAN.

Here, the PVDF/PAN electrospun film-based triboelectric nanogenerator (PP-TENG) was designed to harvest mechanical energy. The PVDF/PAN electrospun film acts as the negative triboelectric material, while the nylon film serves as the positive counterpart. The PVDF/PAN film exhibits uniform morphology, excellent flexibility, and optimal triboelectric performance at a PAN concentration of 4%, underscoring its suitability for flexible TENG applications and the critical role of PAN content optimization in enhancing output performance. The PVDF/PAN composite film demonstrates remarkable performance improvements over the pure PVDF film. The enhancements include over 2.3 times higher V_OC, 2.72 times higher I_SC, and 1.92 times greater Q_SC. The PP-TENG achieves an open-circuit voltage (V_OC) of 160 V, a short-circuit current (I_SC) of 60 μA, and a transferred charge (Q_SC) of 87 nC. Its maximum power output reaches ∼1.99 mW at an optimal load resistance of 2 MΩ. Furthermore, the PP-TENG demonstrates significant potential for health monitoring and energy harvesting applications. It can efficiently charge capacitors for powering low-energy devices while providing sensitivity to environmental factors like humidity. Its versatility is highlighted in various health monitoring scenarios, including motion tracking (finger and wrist bending), respiratory monitoring, and gait analysis, where it can distinguish between normal and abnormal patterns. This makes the PP-TENG a promising candidate for self-powered wearable health monitoring systems and fitness tracking.

The materials utilized in this study were procured from reputable suppliers to ensure consistency and quality. Poly(vinylidene fluoride) (PVDF) powder was obtained from Shanghai Yujia Plastic Raw Materials Co., Ltd., China. Polyacrylonitrile (PAN) powder was sourced from Shaanxi Guben Biotechnology Co., Ltd., China. Analytical-grade N,N-dimethylformamide (DMF, ≥99%) and acetone were supplied by Shandong Mingcheng New Materials Co., Ltd., China. Nylon film was acquired from Linyi Sirius Plastic Products Co., Ltd., China, while copper tape and acrylic boards were procured from Dongguan Yuanteng Electronic Materials Co., Ltd. and Guangzhou ByteDance Technology Co., Ltd., China, respectively.

The preparation of PVDF/PAN films followed a systematic procedure to ensure high-quality outcomes. Initially, PVDF and PAN powders were accurately weighed in a mass ratio of 5:3 and transferred into a glass beaker. A solvent mixture of DMF and acetone, prepared in a volume ratio of 8:2, was then gradually added to the beaker containing the PVDF/PAN powders. The resulting mixture was stirred at 60 °C for 2 h to achieve complete dissolution and preliminary homogenization, yielding a PVDF/PAN solution with a concentration of 12% (w/v). To enhance the uniformity and stability of the mixture, the solution was subjected to additional stirring at room temperature (∼25 °C) using a magnetic stirrer for 3 h. The fully homogenized solution was subsequently utilized in the electrospinning process to fabricate PVDF/PAN films. As shown in Figs. 1(a) and 1(b), electrospinning was conducted under a high electric field generated by a high-voltage direct current power supply, with the process parameters optimized for consistent film production. The applied voltage was set to 18 kV, the feed rate to 0.6 ml/h, and the distance between the syringe tip and the collector (TCD) to 20 cm. The film thickness was precisely controlled by adjusting the electrospinning duration. The resulting PVDF/PAN film exhibited a uniform microstructure and stable performance, meeting the requirements for subsequent applications.

In Fig. 1(c), the fabrication process of the PVDF/PAN membrane-based device is illustrated. The procedure begins with a plastic substrate [Fig. 1(c1)], which serves as the base material for device construction. In Fig. 1(c2), a copper layer is adhered to the plastic substrate, forming a conductive electrode layer. Subsequently, in Fig. 1(c3), the electrospun PVDF/PAN membrane is applied over the copper layer, completing the structural assembly. This multilayer structure integrates the flexible properties of the plastic substrate with the conductive functionality of the copper electrode and the triboelectric characteristics of the PVDF/PAN membrane, providing the foundational configuration for the PP-TENG device. Figure 1(d) demonstrates the structural schematic of the assembled PP-TENG. The device comprises two key components: the PVDF/PAN membrane as the triboelectric active layer and the copper layer as the electrode. The connection to an external resistor signifies the device’s capability to generate and transfer electrical signals, showcasing its potential for energy harvesting applications.

In Fig. 1(f), the scanning electron microscopy (SEM) image of the PVDF/PAN membrane is presented, highlighting its nanofibrous morphology. The image demonstrates a uniform distribution of interconnected fibers with diameters in the micro- to nanoscale range. These fibers form a porous network, which is critical for enhancing surface area and facilitating effective charge transfer during triboelectric interactions. The observed morphology indicates that the electrospinning process was successful in producing a highly uniform and interconnected structure, essential for the functional performance of the membrane in TENGs. Figure 1(g) depicts the X-ray diffraction (XRD) pattern of the PVDF/PAN membrane, revealing the crystallographic characteristics of the composite material. The diffraction peaks are assigned to the characteristic planes of PAN, including the (100) and (110) reflections, while additional peaks correspond to the α and β phases of PVDF. The coexistence of these peaks indicates a synergistic crystalline structure formed by the PVDF and PAN components, which is expected to enhance the mechanical stability and triboelectric properties of the membrane. The predominance of the β-phase in PVDF suggests a high degree of polarization, which is advantageous for optimizing the electrical output of the PP-TENG device. A magnetic stirrer (C-MAG HS7) was employed to achieve consistent and thorough mixing of the prepared solutions. The electrospinning process for fabricating a PVDF/PAN membrane was conducted using a YFSP-T electrospinning system. The V_OC, I_SC, and Q_SC were measured with precision using a Keithley 6514 electrometer. Furthermore, an adjustable mechanical motor, custom-designed for this study, was used to apply controlled actuation forces, allowing for a systematic evaluation of the material’s performance under specific mechanical conditions.

Figure 2(a) illustrates the working principle of the PP-TENG during its contact-separation operation mode. The sequence provides a step-by-step depiction of charge generation, accumulation, and transfer facilitated by the device’s layered structure. In Fig. 2(a1), as the nylon layer approaches the PVDF/PAN membrane under external force, surface contact occurs, initiating charge transfer due to the difference in triboelectric polarity. Positive charges accumulate on the surface of the nylon, while negative charges are retained on the PVDF/PAN membrane, creating an electric dipole within the system. In Fig. 2(a2), the external force is released, and the layers begin to separate. During this process, the displacement of charges between the triboelectric surfaces induces a potential difference across the electrodes, driving electron flow through the connected external circuit. This separation phase is critical for generating an electrical signal. In Fig. 2(a3), the layers are fully separated, maximizing the charge separation and the potential difference across the electrodes. At this stage, the transferred charges stabilize, and the system is ready for subsequent cycles of operation. In Fig. 2(a4), the external force is reapplied, bringing the layers back into contact. The compression restores equilibrium by neutralizing the surface charges, completing the cycle, and enabling continuous energy harvesting. The cyclic contact and separation motions, facilitated by the PP-TENG device’s mechanical flexibility, enable consistent triboelectric charge generation, making the PP-TENG suitable for applications in mechanical energy harvesting and self-powered sensing systems.

In Fig. 2(b1), the fabricated PVDF/PAN film is displayed, showcasing its uniform morphology and smooth surface, indicative of the successful electrospinning process. The uniform distribution of fibers and the film’s consistent structure are critical for enhancing its triboelectric properties. In Fig. 2(b2), the flexibility of the PVDF/PAN film is demonstrated, where the material can be easily bent without damage. This flexibility ensures the film’s adaptability for diverse applications, including wearable devices and dynamic energy harvesting systems. The mechanical robustness and pliability of the PVDF/PAN membrane highlight its suitability for practical deployment in flexible and portable TENGs. In Fig. 2(c), the V_OC for the PVDF film is ∼56.03 V, whereas the PVDF/PAN composite film achieves around 107.78 V. This represents an increase of over 1.92 times. The incorporation of PAN into the PVDF matrix improves surface charge density and triboelectric performance, resulting in a significantly higher V_OC. Figure 2(d) compares the I_SC of the two films. The PVDF film produces a maximum current of about 4.51 μA, while the PVDF/PAN film generates nearly 12.31 μA. This corresponds to a threefold enhancement. PAN enhances the charge capture and separation efficiency on the composite material’s surface, leading to a substantial improvement in triboelectric current output. In Fig. 2(e), the Q_SC of the PVDF film is ∼26.36 nC, whereas the PVDF/PAN composite film achieves around 50.62 nC, indicating an increase of 1.92 times. This suggests that the PVDF/PAN composite film is significantly more effective at capturing triboelectric charges, with greatly improved charge storage capabilities. Hence, the PVDF/PAN composite film demonstrates remarkable performance improvements over the pure PVDF film. The enhancements include over 2.3 times higher V_OC, 2.72 times higher I_SC, and 1.92 times greater Q_SC. These substantial improvements in electrical performance significantly boost the output capabilities of the PP-TENG, making it more promising for applications in energy harvesting and self-powered sensing technologies.

In Fig. 3(a), the V_OC for different PAN concentrations is shown. The voltage increases with higher PAN concentrations, reaching a peak at 4% PAN, with a maximum output of ∼140 V. Beyond this concentration, the V_OC begins to decline, likely due to excessive PAN content affecting the dielectric properties and reducing charge transfer efficiency. This trend underscores the importance of optimizing the PAN concentration for maximum voltage output. Figure 3(b) illustrates the I_SC as a function of PAN concentration. Similar to the voltage output, the current exhibits a peak at 4% PAN, achieving a maximum of ∼27.47 μA. The decline in I_SC at higher PAN concentrations suggests that excessive PAN content disrupts the uniformity of the electrospun fibers, thereby impeding charge generation and transport. Figure 3(c) depicts the Q_SC for the same PAN concentrations. The Q_SC also reaches its maximum value at 4% PAN, indicating optimal charge transfer and storage capabilities at this concentration. The reduction in Q_SC at higher PAN levels further corroborates the adverse effects of excessive PAN on the triboelectric performance. The optimization of PAN concentration at 4% can be attributed to the interplay between charge transfer efficiency and mechanical properties. PAN, as a polymer with strong electron-withdrawing nitrile groups (–C≡N), enhances the triboelectric charge density by increasing electron capture capability. At low PAN concentrations (1%–2%), the charge transfer efficiency remains suboptimal due to insufficient electron affinity. However, as the PAN content increases, the triboelectric performance improves, reaching a maximum at 4% PAN. Beyond this threshold, excessive PAN disrupts the uniformity of the electrospun fibers, leading to reduced dielectric performance and mechanical brittleness. The high PAN content also increases the stiffness of the composite film, which negatively affects its flexibility and adhesion to the counter triboelectric layer, ultimately reducing charge generation efficiency. Therefore, 4% PAN achieves the best balance between high charge density and mechanical stability, resulting in the highest V_OC, I_SC, and Q_SC values observed in this study. In Fig. 3(d), the V_OC under different frequencies is presented. The results demonstrate that the V_OC remains relatively constant at ∼160 V, regardless of the applied frequency. This behavior indicates that the triboelectric voltage is primarily governed by the intrinsic material properties, such as the dielectric and triboelectric characteristics of the PVDF/PAN film and the counter electrode, rather than the external frequency. The stability of V_OC under varying mechanical frequencies underscores the robustness of the device in maintaining voltage output under different operating conditions. Figure 3(e) shows the variation in I_SC with increasing frequency. Unlike V_OC, the I_SC exhibits a clear increasing trend as the frequency rises. At 2 Hz, the I_SC is ∼12 μA, whereas at 6 Hz, it reaches around 60 μA. This behavior can be attributed to the higher rate of contact and separation cycles at increased frequencies, which accelerates the movement of charges and enhances current flow through the external circuit. The dependence of I_SC on frequency highlights the dynamic nature of charge transfer in triboelectric systems and the potential for improved current output at higher operational frequencies. In Fig. 3(f), the Q_SC is shown to remain nearly constant across the tested frequency range, similar to V_OC. The consistent Q_SC, ∼87 nC, suggests that the total amount of charge transferred during each contact-separation cycle is independent of the frequency. This behavior implies that the charge generation process is determined by the contact electrification mechanism, which remains stable regardless of how quickly the cycles are performed. The stability of Q_SC is indicative of the high reliability of the TENG in maintaining consistent charge transfer under varying operational conditions. In Fig. 3(g), the relationship between the output voltage and current as a function of external load resistance is depicted. The voltage increases significantly as the resistance rises, while the current exhibits an inverse trend. This behavior reflects the fundamental Ohmic relationship, where the load resistance directly impacts the distribution of voltage and current in the circuit. The observed trends indicate that the PP-TENG can adapt its output characteristics to match varying load conditions, making it suitable for powering devices with different electrical requirements. Figure 3(h) illustrates the power output as a function of load resistance. The power initially increases, reaches a maximum value of ∼1.99 mW at an optimal resistance of 2 MΩ, and then decreases as the resistance continues to rise. This behavior is consistent with the maximum power transfer theorem, where maximum power is delivered to the load when the load resistance matches the internal resistance of the PP-TENG device. The peak power output at 2 MΩ demonstrates the high efficiency of the PP-TENG in energy conversion under optimized load conditions, showcasing its potential for practical energy harvesting applications. In Fig. 3(i), the long-term durability of the PP-TENG is evaluated over 50 000 continuous operational cycles, with the V_OC measured both at the beginning and at the end of the cycling test. The results demonstrate remarkable stability, as no significant degradation in V_OC is observed, indicating the excellent structural integrity and mechanical resilience of the device. The consistent electrical output before and after prolonged mechanical actuation highlights the superior fatigue resistance of the PVDF/PAN-based triboelectric layers, ensuring sustained energy generation even under extended operational conditions. This high durability is particularly crucial for real-world applications, where TENG-based devices are frequently subjected to repetitive mechanical forces, such as those encountered in wearable electronics, biomechanical sensing, and smart textiles. The ability of the PP-TENG to maintain stable performance over an extensive number of cycles underscores its suitability for long-term deployment in self-powered health monitoring systems, motion detection applications, and other energy harvesting scenarios. Furthermore, these results suggest that the electrospun PVDF/PAN composite film effectively mitigates mechanical degradation, reinforcing its potential for flexible and high-performance TENG applications. Future research may focus on further enhancing durability through material optimization and encapsulation strategies, ensuring even greater reliability under extreme environmental conditions.

In Fig. 4(a), the V_OC is shown to increase linearly with the gap distance, rising from ∼80 V at 1 mm to 160 V at 9 mm. This behavior is attributed to the enhanced electric potential difference generated by larger separation distances, which amplify the electrostatic induction effect. Figure 4(b) illustrates the I_SC for different gap distances. The current increases steadily with the gap distance, with values ranging from ∼13 μA at 1 mm to 30 μA at 9 mm. This trend is consistent with the enhanced charge transfer and stronger electric field induced by greater separation distances during the contact-separation cycles. In Fig. 4(c), the Q_SC is depicted as a function of the gap distance. The transferred charge increases proportionally with the gap distance, reaching ∼110 nC at 9 mm. This result confirms that larger gap distances facilitate more effective charge accumulation and transfer due to improved surface charge separation during operation. In Fig. 4(d), the V_OC increases significantly with the applied force, from ∼82 V at 5 N to 200 V at 25 N. The increased voltage can be attributed to improved contact intimacy and enhanced triboelectric charge generation as the applied force intensifies. Figure 4(e) presents the I_SC as a function of applied force. Similar to V_OC, the I_SC exhibits a positive correlation with force, increasing from ∼11 μA at 5 N to 24 μA at 25 N. The enhanced current is due to more effective charge transfer enabled by the stronger compressive forces, which increase the contact area and improve triboelectric charge generation. In Fig. 4(f), the Q_SC also shows a clear dependence on the applied force, rising from ∼40 nC at 5 N to 101 nC at 25 N. This behavior highlights the importance of applied force in maximizing charge transfer efficiency, as higher forces lead to better contact and separation dynamics between the triboelectric layers.

Figure 5(a) depicts the circuit configuration of the PP-TENG integrated with a rectifier and capacitor for energy storage. The rectifier ensures unidirectional current flow, allowing the capacitor to store energy harvested by the PP-TENG. Figure 5(b) shows the charging curves for capacitors with different capacitances (5, 10, and 15 μF). The voltage across the capacitors increases with time, with smaller capacitors (5 μF) charging more rapidly due to their lower energy storage capacity. The results highlight the feasibility of using the PP-TENG for powering low-energy devices by efficiently storing the harvested energy. The ability to charge capacitors demonstrates the PP-TENG’s practical application in self-powered systems for portable and wearable electronics. Figure 5(c) examines the impact of environmental humidity on the output performance of the PP-TENG. The results show a significant decrease in V_OC as humidity rises from 30% to 70%, with the V_OC dropping from 160 to ∼80 V. This decline is primarily attributed to the formation of a moisture layer on the surface of the triboelectric materials, which increases surface conductivity and facilitates charge dissipation, thereby inhibiting effective charge retention and transfer. In addition, excessive humidity can alter the dielectric properties of the triboelectric layers, further reducing the overall charge separation efficiency. These findings highlight the crucial role of environmental conditions in determining the stability and reliability of TENG-based devices, particularly for long-term applications in humid environments. To mitigate the adverse effects of humidity, potential solutions include surface modification techniques, such as hydrophobic coatings, material engineering strategies to improve water resistance, and encapsulation methods to enhance environmental durability. Incorporating these approaches can significantly improve the operational stability of the PP-TENG, making it more suitable for real-world applications in wearable electronics and healthcare monitoring. In Fig. 5(d), the PP-TENG is attached to a finger, generating a voltage signal during bending motions. The consistent and repeatable voltage peaks indicate the PP-TENG’s capability to capture subtle mechanical deformations, enabling its application in monitoring finger movements for rehabilitation or gesture recognition. Figure 5(e) illustrates the voltage response of the PP-TENG during wrist bending. The output voltage reaches ∼40 V, showcasing the device’s ability to detect larger-scale body motions. This functionality could be employed in wearable devices for tracking joint movements or providing feedback for physical therapy exercises. Figure 5(f) demonstrates the PP-TENG’s use in respiratory monitoring by attaching it to a mask. The cyclic voltage output corresponds to inhalation and exhalation patterns, with distinct peaks representing each respiratory cycle. This application is particularly valuable for respiratory health monitoring, offering a non-invasive method to track breathing rates and detect irregularities such as apnea or shallow breathing. Such a system could be integrated into smart healthcare devices for real-time respiratory diagnostics and health management. The multi-functionality of the PP-TENG highlights its versatility for both energy harvesting and health monitoring. The ability to charge capacitors demonstrates its potential for powering small electronics, while its environmental sensitivity points to the need for optimization in specific applications. The health monitoring demonstrations underline its relevance in wearable technology, with applications ranging from motion detection to respiratory monitoring. These features make the PP-TENG a promising candidate for self-powered, flexible devices in healthcare, fitness tracking, and environmental sensing. Future research could focus on improving its performance under varying environmental conditions and integrating the device into more complex health monitoring systems, such as multi-sensor networks or real-time diagnostic platforms. Figure 5(g) illustrates the integration of a PP-TENG into a shoe, showcasing its ability to harvest bio-mechanical energy during walking or other physical activities. The close-up image demonstrates the compact design and flexibility of the PP-TENG, making it suitable for embedding into wearable devices like footwear. This configuration enables real-time collection of mechanical energy from foot movements, laying the foundation for self-powered health monitoring systems. Figure 5(h) compares the voltage signals generated by the PP-TENG under two different gait patterns: simulated knee injury gait and healthy gait. For the knee injury gait, the generated voltage signals are irregular, with significantly lower amplitudes and inconsistent waveforms. In contrast, the healthy gait produces regular and higher-amplitude voltage signals, reflecting stable and uniform bio-mechanical movements. These results demonstrate the PP-TENG’s sensitivity to variations in walking patterns, making it a valuable tool for detecting abnormalities in gait, such as those caused by injuries or chronic health conditions. Hence, the PP-TENG shows excellent potential for health monitoring by capturing bio-mechanical signals during physical activities. Its ability to distinguish between normal and abnormal gait patterns highlights its utility in applications such as rehabilitation monitoring, injury detection, and fitness tracking. The self-powered nature of the PP-TENG further enhances its appeal, enabling continuous, maintenance-free operation for wearable health monitoring systems. We have briefly highlighted that, in addition to energy harvesting and health monitoring, the PP-TENG could be applied in human-machine interactions, environmental sensing, and intelligent systems.

In summary, this study developed a PVDF/PAN electrospun film-based triboelectric nanogenerator (PP-TENG) for efficient mechanical energy harvesting. The PVDF/PAN film, optimized at a PAN concentration of 4%, served as the negative triboelectric material, paired with Nylon as the positive counterpart. The PVDF/PAN composite film demonstrates remarkable performance improvements over the pure PVDF film. The enhancements include over 2.3 times higher V_OC, 2.72 times higher I_SC, and 1.92 times greater Q_SC. The material exhibited uniform morphology, excellent flexibility, and enhanced triboelectric performance, achieving an V_OC of 160 V, a I_SC of 60 μA, and a Q_SC of 87 nC, with a maximum power output of 1.99 mW at an optimal load resistance of 2 MΩ. Beyond energy harvesting, the PP-TENG demonstrated significant potential in health monitoring by effectively detecting mechanical deformations from finger and wrist movements and tracking respiratory patterns. These features position the PP-TENG as a versatile and promising candidate for applications in rehabilitation, physical therapy, respiratory diagnostics, and wearable, self-powered healthcare systems, advancing technologies in fitness tracking, health management, and environmental sensing. Future research directions may focus on incorporating biodegradable or bio-derived triboelectric materials, such as cellulose, silk fibroin, or chitosan, to enhance the sustainability of TENGs. In addition, adopting eco-friendly fabrication methods, such as solvent-free processing or water-based electrospinning, could further reduce the environmental impact of these devices while maintaining high-performance output.

The author has no conflicts to disclose.

Yuhong Liu: Conceptualization (lead); Data curation (lead); Formal analysis (lead); Funding acquisition (lead); Investigation (lead); Methodology (lead); Project administration (lead); Resources (lead); Software (lead); Supervision (lead); Validation (lead); Visualization (lead); Writing – original draft (lead); Writing – review & editing (lead).

The data that support the findings of this study are available from the corresponding author upon reasonable request.