Ordered Macro-Microporous Metal-Organic Framework Single Crystals and Their Derivatives for Rechargeable Aluminum-Ion Batteries.

Constructing ordered hierarchical porous structures while maintaining their overall crystalline order is highly desirable but remains an arduous challenge. Herein, we successfully achieve the growth of single-crystalline metal-organic frameworks (MOFs) in three-dimensional (3D) ordered macroporous template voids by a saturated solution-based double-solvent-assisted strategy with precise control over the nucleation process. The as-prepared single-crystalline ordered macro-microporous Co-based MOFs (SOM ZIF-67) exhibit an ordered macro-microporous structure with robust single-crystalline nature. Moreover, SOM ZIF-67 can serve as a precursor to derive 3D-ordered macroporous cobalt diselenide@carbon (3DOM CoSe2@C) through a facile carbonization-selenization treatment. The as-derived 3DOM CoSe2@C can well preserve the 3D-ordered macroporous structure of the precursor. More importantly, CoSe2 nanoparticles could be uniformly confined in the conductive ordered macroporous carbon framework, affording regularly interconnected macroporous channels and large surface area. As a result, when evaluated as a cathode material for aluminum-ion batteries, the ordered macroporous structure could not only effectively facilitate the diffusion of large-sized chloroaluminate anions but also increase the contact area with electrolyte and provide more exposed active sites, thereby exhibiting superior reversible rate capacity (86 mA h g-1 at 5.0 A g-1) and remarkable cycling performance (125 mA h g-1 after 1000 cycles at 2.0 A g-1).