Thermally Resistant, Mechanically Robust, Enamel-Inspired Hydroxyapatite/Polyethylene Nanocomposite Battery Separator

Microporous polyethylene (PE) membrane is a representative lithium-ion battery (LIB) separators but regularly shrinks especially in high-temperature conditions, and is facilely pierced while growing Li dendrites, leading to severe consequences such as short circuits, thermal runaway, and even explosion. Herein, this article reports a quasi-continuous strategy that utilizes in situ enamel mineralization engineering followed by thermal treatment to easily develop a large-area, 3D interlaced hydroxyapatite nanosheets array-reinforced PE nanocomposite separator with robust mechanical properties and excellent resistance to thermal shrinkage. Specifically, the 120 degrees C-heated nanocomposite possesses excellent breaking stress, an ultrahigh toughness of approximate to 434.4 MJ m-3, and an enhanced friction coefficient of approximate to 0.69, which are distinctly higher than those of commercial PE separators, respectively, and far exceeding those of reported ceramic modified-PE separators. The elongation of the resultant nanocomposite can achieve an extraordinary approximate to 2456.4% without any fracture under a 180 degrees C-heating temperature. In situ observation and finite element simulation indicate that the impressive mechanical and thermostable integration profits from the co-effect of efficient energy dissipation at organic-inorganic interfaces and mechanically interlocked, mutually-supported hybrid microstructure. The enamel-inspired separator can be potentially applied in safer high-temperature LIBs and this strategy provides a valuable guide to develop other high-performance polymer-based nanocomposites. A quasi-continuous preparation strategy that utilizes in situ enamel mineralization engineering followed by thermal treatment is proposed to develop a large-area, enamel-3D interlaced hydroxyapatite nanosheets array-reinforced polyethylene nanocomposite separator with robust mechanical properties and excellent resistance to thermal shrinkage. The nanocomposite separator can be potentially applied in safer high-temperature Li-ion batteries.image

Automated summary

This article reports a strategy that utilizes in situ enamel mineralization engineering followed by thermal treatment to develop a large-area, 3D interlaced hydroxyapatite nanosheets array-reinforced polyethylene nanocomposite separator with strong mechanical properties and excellent resistance to thermal shrinkage. The nanocomposite separator shows better performance than commercial PE separators and ceramic modified-PE separators, with high breaking stress, ultrahigh toughness, enhanced friction coefficient, and extraordinary elongation without fracture under high temperature. The impressive mechanical and thermostable integration is attributed to the efficient energy dissipation at organic-inorganic interfaces and the mechanically interlocked, mutually-supported hybrid microstructure. This enamel-inspired separator has potential applications in safer high-temperature Li-ion batteries and provides a valuable guide for developing other high-performance polymer-based nanocomposites.