High-Performance and Rapid-Response Electrical Heaters Derived from Cellulose Nanofiber/Silver Nanowire Nanopapers for Portable Thermal Management

High-performance electrical heaters with outstanding flexibility, superior portability, and mechanical properties are highly desirable for portable thermal management. However, it is still a huge challenge to simultaneously achieve competent electrical heating performances and excellent mechanical properties. Herein, inspired by the Janus structure, versatile electrical heaters are developed via a sequential assembly followed by a hot-pressing strategy. The elaborately designed Janus structure is composed of a nanofibrillated cellulose (NFC) layer and a partially wrapped silver nanowire (AgNW) skeleton in the NFC substrate. Owing to the perfect introduction of nano-soldered points induced by thermal welding decoration, the resultant NFC/AgNW papers (NAPs) possess great flexibility, excellent mechanical strength (176.75 MPa), extremely low sheet resistance (0.60 Omega/sq), and superior electrical stabilities against mechanical deformations. Moreover, benefitting from these fascinating attributes, the NAP-based electrical heaters exhibit a remarkable heating temperature (similar to 220 degrees C), ultrafast electro-thermal response (<10 s), and groundbreaking long-term stability (similar to 105 degrees C for >186 h) and repeatability (>20,000 cycles) with low AgNW contents and driving voltages (0.5-5.0 V), which far surpass those of the previously reported and conventional indium tin oxide-based Joule heaters. Impressively, large-area production feasibilities of NAPs are demonstrated and assembled into multifunctional applications, including personal thermal management, healthcare thermotherapy, multifunctional cups, and smart homes, indicating their promising potential for wearable devices, artificial intelligence, and specific heating systems in the fields of aerospace, military, and intelligent life.

Automated summary

High-performance electrical heaters with outstanding flexibility, superior portability, and mechanical properties have been developed via a sequential assembly followed by a hot-pressing strategy. The resultant electrical heaters exhibit great flexibility, excellent mechanical strength, low sheet resistance, and superior electrical stabilities. They also show remarkable heating temperature, ultrafast electro-thermal response, and groundbreaking long-term stability and repeatability, surpassing previously reported heaters. The large-area production feasibilities of these heaters are also demonstrated, making them promising for various applications.