title: Rational Integration of Inbuilt Aperture with Mesoporous Framework in Unusual Asymmetrical Yolk-Shell Structures for Energy Storage and Conversion.
abstract: Despite the attractive benefits of hollow structures as electrodes for advanced energy storage-conversion capabilities, one prevailing shortcoming is their compromised structural integrity and volumetric energy density due to the introduction of an ultrathin shell with an excessively underutilized large hollow cavity. Herein, we report a facile and template-free synthetic route to realize unusual asymmetrical yolk-shell (AYs) structures composed of mixed-valence NiCo2O4material. Explicitly, this work highlights the unusual off-central core, an AYs structure that encompasses a hemispherical hollow interior, and a mesoporous solid counterpart. As such, it retains desirable hollow structural characteristics while favorably precludes the excessive unexploited hollow interior space for increased active material packing. Unlike the conventional symmetrical yolk-shell (SYs) which is composed of a porous shell framework radially throughout the structure, the mesoporous solid constitution of the AYs structure offers an inbuilt reinforced framework to support the partial porous shell and concurrently leaves sufficient void for volumetric buffering. Another unique structural feature of the AYs structure is the formation of a submicron aperture or opening on the shell that enhances accessibility of electrolyte diffusion. All of these synergistic structural features of NiCo2O4AYs structures enhance the pseudocapacitive and electrocatalytic properties.
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore , 4 Engineering Drive 3, Singapore 117583.
authors.forename: Ting
authors.initials: T
authors.lastname: Zhu
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore , 4 Engineering Drive 3, Singapore 117583.
authors.forename: Liangliang
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore , 4 Engineering Drive 3, Singapore 117583.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore , 4 Engineering Drive 3, Singapore 117583.|Engineering Science Programme, National University of Singapore , 9 Engineering Drive 1, Singapore 117575.|Institute of Materials Research and Engineering , A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602.
authors.forename: Ghim Wei
authors.initials: GW
authors.lastname: Ho
keywords: NiCo2O4; mesoporous; oxygen evolution reaction OER; supercapacitor; yolk−shell