High-Throughput Electrospinning System| Micro-nano fibers with core-shell forenhancing flame retardancy and high.temperature resistance of biodegradabletriboelectric materials

Nano Energy by Academician Wang Shuangfei’s Team at Guangxi University: Flame-Retardant Biodegradable Triboelectric Material with Core-Shell Fiber Structure

Research Background:
With the advent of the intelligent era, advanced technologies such as the Internet of Things, big data, and artificial intelligence have driven the rapid development of portable wearable devices. However, these devices require power sources and are prone to failure or damage in high-temperature and fire environments. Although triboelectric nanogenerators (TENGs), based on the coupling effect of contact electrification and electrostatic induction, offer a new solution, charge dissipation caused by thermionic emission under high temperatures and material destruction by flames severely limit TENG applications. Thus, ensuring stable performance and effective use of TENGs in extreme environments remains a critical challenge.

Article Summary:
Recently, Associate Professor Duan Qingshan from Academician Wang Shuangfei’s team at Guangxi University, collaborating with Dr. He Juanxia from the School of Resources, Environment, and Materials, developed a flame-retardant polylactic acid (PLA)-based triboelectric material with a core-shell structure, achieving stable self-powered sensing in high-temperature environments. The material’s double-layer hydrogen bond crosslinking enhances the dispersion of the flame-retardant shell (PLA/calcium phytate, PLA/PA-Ca) and the triboelectricity-boosted core (PLA/carboxylated carbon nanotubes, PLA/C-MWCNT), improving both flame retardancy and triboelectric performance. A single-electrode wireless self-powered alarm system with adjustable thresholds was constructed for high-temperature and fire warnings.The study, titled "Micro-nano fibers with core-shell for enhancing flame retardancy and high-temperature resistance of biodegradable triboelectric materials," was published in Nano Energy. Dr. He Juanxia is the first author, with Associate Professor Duan Qingshan as the corresponding author. Contributors include Ruan Xingzhe, Yang Lihong, Liu Zechun, Liao Kezhang, Xie Xuecai, Shu Xueming, Zhan Yongzhong, Pang Xingzhi, Yang Wenchao, and Zhang Hanbing.

Graphical Abstract:

1. Design Strategy: Core-shell flame-retardant triboelectric fibers were fabricated via coaxial electrospinning. PA-Ca in the shell forms P=O···H hydrogen bonds with PLA, while C-MWCNT in the core forms C=O···H bonds. This dual-network prevents particle aggregation and enhances flame retardancy and triboelectricity.

   

   
   

   Figure 1. Design and application of flame-retardant PLA-based triboelectric material.

   
   

2. Material Characterization: Modified PLA fibers exhibit uniform morphology, increased diameter, and improved crystallinity. FTIR, XRD, XPS, and DSC analyses confirm hydrogen bonding and phase transition (β→α). Tensile strength and elongation are also enhanced.

   

   
   

   Figure 2. Structure and characterization of flame-retardant PLA-based triboelectric material.

   
   

3. Flame Retardancy: With higher PA-Ca content, dripping vanishes (VTM-0 rating). Combustion tests show reduced heat release and viscous melt that suppresses flame spread. Dense char layers isolate heat/oxygen, while PO· radicals quench flames.

   

   
   

   Figure 3. Flame-retardant performance of PLA-based triboelectric material.

   
   

4. Biodegradability: Protease K degradation tests reveal >70% weight loss in 4 days. C=O absorbance decline confirms PLA ester hydrolysis into lactic acid, demonstrating eco-friendliness.

   

   Figure 4. Biodegradability of flame-retardant PLA-based triboelectric material.

   
   

5. Triboelectric Performance: C-MWCNT boosts electron conduction, and hydrogen bonds enhance polarization. Output voltage/current increase 5.1×/4.5× vs. pure PLA. At 160°C, 71.29% voltage retention is achieved, with only 3% drop after 5,000 cycles. Post-combustion (20 s), 13.4% output remains.

   

   Figure 5. Triboelectric performance of flame-retardant PLA-based triboelectric material.

   
   

6. Applications: A single-electrode TENG-based wireless sensor converts motion (e.g., finger tapping) into signals for fire alarms (0.1–0.16 V threshold at 160°C) and posture monitoring, even post-flame exposure.

   

   Figure 6. Self-powered sensor for high-temperature and fire alarm applications.

   
   

   Conclusion:
   The core-shell nanofiber TENG exhibits exceptional flame retardancy, high-temperature resistance (52.19 V at 160°C; 9.81 V post-20s flame), durability (3% decay after 5,000 cycles), and biodegradability. It enables real-time fire alerts and motion tracking, showing great potential for smart firefighting and human-machine interaction.