Separators play a critical role in lithium-ion batteries. However, the restrictions of thermal stability and inferior electrical performance in commercial polyolefin separators significantly limit their applications under harsh conditions. Here, we report a cellulose-assisted self-assembly strategy to construct a cellulose-based separator massively and continuously. With an ultrahigh ionic conductivity in electrolytes of 3.7 mS·cm⁻¹ and the ability to regulate ion transport, the obtained separator is a promising alternative for high-performance lithium-ion batteries. In addition, integrated with high thermal stability, the cellulose-based separator endows batteries with high safety at high temperatures, greatly expanding the application scenarios of energy storage devices in extreme environments.

Different forms of construction materials (e.g., paints, foams, and boards) dramatically improve the quality of life. With the increasing environmental requirements for buildings, it is necessary to develop a comprehensive sustainable construction material that is flexible in application and exhibits excellent performance, such as fireproofing and thermal insulation. Herein, an adjustable multiform material strategy by water regulation is proposed to meet the needs of comprehensive applications and reduce environmental costs. Multiform gels are constructed based on multiscale cellulose fibers and hollow glass microspheres, with fireproofing and thermal insulation. Unlike traditional materials, this multiscale cellulose-based gel can change forms from dispersion to paste to dough by adjusting its water content, which can realize various construction forms, including paints, foams, and low-density boards according to different scenarios and corresponding needs.