In the present study, we report the synthesis of a high-quality, single-crystal hexagonal β-Co(OH)2 nanosheet, exhibiting a thickness down to ten atomic layers and an aspect ratio exceeding 900, by using graphene oxide (GO) as an exfoliant of β-Co(OH)2 nanoflowers. Unlike conventional approaches using ionic precursors in which morphological control is realized by structure-directing molecules, the β-Co(OH)2 flower-like superstructures were first grown by a nanoparticle-mediated crystallization process, which results in large 3D superstructure consisting of ultrathin nanosheets interspaced by polydimethoxyaniline (PDMA). Thereafter, β-Co(OH)2 nanoflowers were chemically exfoliated by surface-active GO under hydrothermal conditions into unilamellar single-crystal nanosheets. In this reaction, GO acts as a two-dimensional (2D) amphiphile to facilitate the exfoliation process through tailored interactions between organic and inorganic molecules. Meanwhile, the on-site conjugation of GO and Co(OH)2 promotes the thermodynamic stability of freestanding ultrathin nanosheets and restrains further growth through Oswald ripening. The unique 2D structure combined with functionalities of the hybrid ultrathin Co(OH)2 nanosheets on rGO resulted in a remarkably enhanced lithium-ion storage performance as anode materials, maintaining a reversible capacity of 860 mA h g(-1) for as many as 30 cycles. Since mesocrystals are ubiquitous and rich in morphological diversity, the strategy of the GO-assisted exfoliation of mesocrystals developed here provides an opportunity for the synthesis of new functional nanostructures that could bear importance in clean renewable energy, catalysis, photoelectronics, and photonics.

No abstract

… in flower-like mesocrystals are interspaced by organic additives and held together by complex intersheet interactions. Therefore, the ability to exfoliate mesocrystals requires an appropriate modifier that can interact with the organic additive and weaken the interaction between the nanosheets. In their Full paper on page 12444 ff., S. Deng, H.-M. Fan et al. show that graphene oxide (GO), a quasi-two-dimensional (2D) structure tethered with abundant functional groups with dual molecular-colloidal properties, acts as an exfoliant of the mesocrystals.