Inorganic Hydrogels can be Flexible and Highly Extensible
Tongming Zhou, Yan Wang, Jiu-Long Zhou, Lifeng Yao, Ke He, Lixun Chen, Song Zhang, Hong Liu, Xiaodong Chen, Shuxun Cui
Abstract
Abstract Inorganic hydrogels have great potential in many applications as sustainable materials, but lack flexibility due to rigid network structures. Here, a novel strategy is proposed—an inorganic polymer hydrogel, prepared by crosslinking long‐chain polyphosphate (LPP) with M 2+ ions (Ca 2+ , Mn 2+ , Mg 2+ , Ni 2+ ), which effectively address the rigidity and fragility issues commonly associated with traditional inorganic gels. With the most stable hydration shell among those ions, Ni 2+ tends to interact indirectly with LPP through hydrogen bonds rather than coordination bonds. The unique Ni 2+ ‐phosphate interaction endows the Ni‐LPP hydrogels with ultrahigh elongation at break (≈15 000×). Further experiments reveal that the Ni 2+ ‐phosphate motif can be applied to other hydrogels as an extension enhancement factor. The highly extensible, good conductive (1.06 ± 0.08 S m −1 ), self‐healing (within 30 s and without stimulation), arbitrarily shapeable, and nonflammable Ni‐LPP inorganic hydrogel indicates a bright future in flexible electronics, environmental remediation, and beyond.