Spray-Assisted Deep-Frying Process for the In Situ
Spherical Assembly of Graphene for Energy-Storage Devices
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Abstract
To take full advantage of graphene
in macroscale devices, it is
important to integrate two-dimensional graphene nanosheets into a
micro/macrosized structure that can fully utilize graphene’s
nanoscale characteristics. To this end, we developed a novel spray-assisted
self-assembly process to create a spherically integrated graphene
microstructure (graphene microsphere) using a high-temperature organic
solvent in a manner reminiscent of deep-frying. This graphene microsphere
improves the electrochemical performance of supercapacitors, in contrast
to nonassembled graphene, which is attributed to its structural and
pore characteristics. Furthermore, this synthesis method can also
produce an effective graphene-based hybrid microsphere structure,
in which Si nanoparticles are efficiently entrapped by graphene nanosheets
during the assembly process. When used in a Li-ion battery, this material
can provide a more suitable framework to buffer the considerable volume
change that occurs in Si during electrochemical lithiation/delithiation,
thereby improving cycling performance. This simple and versatile self-assembly
method is therefore directly relevant to the future design and development
of practical graphene-based electrode materials for various energy-storage
devices