Nacre-Inspired Aramid Nanofibers/Basalt Fibers Composite Paper with Excellent Flame Retardance and Thermal Stability by Constructing an Organic–Inorganic Fiber Alternating Layered Structure

The flame-retardant paper has gradually evolved into a necessary material in various industries as a result of the rising importance of fire safety, energy efficiency, and environmental preservation. Traditional cellulose paper requires the addition of a large amount of flame retardants to achieve flame retardancy, which poses a serious threat to mechanical quality and the environment. Therefore, there is an urgent need to develop inorganic fiber flame-retardant paper with good flexibility, high thermal stability, and inherent flame retardancy. Herein, inspired by the “brick-and-mortar” layered structure of nature nacre, we developed a layered composite paper with a unique alternating arrangement of organic–inorganic fibers by synergistically integrating environmentally sustainable basalt fiber (BF) and high-performance aramid nanofibers (ANFs) through a vacuum-assisted filtration process. The as-prepared ANFs/BF composite paper exhibited low thermal conductivity (0.024 W m–1 K–1), high tensile strength (54.22 MPa), and excellent flexibility. Thanks to its excellent thermal stability, the mechanical strength remains at a high level (92%) after heat treatment at 300 °C for 60 min. Furthermore, the peak heat release rate and smoke generation of ANFs/BF composite paper decreased by 44.6 and 95.3%, respectively. Therefore, the composite paper is promising for applications as a protective layer in flexible electronic devices, cables, and fire-retardant and high-temperature fields.