Showing papers by "Mingming Chen published in 2018"

N-Doped Dual Carbon-Confined 3D Architecture rGO/Fe3O4/AC Nanocomposite for High-Performance Lithium-Ion Batteries

Abstract: To address the issues of low electrical conductivity, sluggish lithiation kinetics and dramatic volume variation in Fe3O4 anodes of lithium ion battery, herein, a double carbon-confined three-dimensional (3D) nanocomposite architecture was synthesized by an electrostatically assisted self-assembly strategy. In the constructed architecture, the ultrafine Fe3O4 subunits (∼10 nm) self-organize to form nanospheres (NSs) that are fully coated by amorphous carbon (AC), formatting core–shell structural Fe3O4/AC NSs. By further encapsulation by reduced graphene oxide (rGO) layers, a constructed 3D architecture was built as dual carbon-confined rGO/Fe3O4/AC. Such structure restrains the adverse reaction of the electrolyte, improves the electronic conductivity and buffers the mechanical stress of the entire electrode, thus performing excellent long-term cycling stability (99.4% capacity retention after 465 cycles relevant to the second cycle at 5 A g–1). Kinetic analysis reveals that a dual lithium storage mechanis...

2D porous carbon nanosheets constructed using few-layer graphene sheets by a “medium-up” strategy for ultrahigh power-output EDLCs

Abstract: 2D porous carbon nanosheets (PCNs) occupy the foreground in the field of electric double-layer capacitors (EDLCs). However, the mass production of PCNs with ultrathin thicknesses is still a serious challenge. Herein, PCNs constructed of few-layer graphene sheets were synthesized from a sulfonated pitch (SP) carbon precursor and soft-template F127 by a “medium-up” strategy. SP serves as a “medium material”, while F127 acts as a “string” and “spacer”, which plays the leading role of structure directing and prevents the self-restacking of small graphene layers. After activation, sample PCN6 with high carbon yield is constructed with a thickness of only 1.3 nm, sufficient specific surface area of 3006 m2 g−1 and high e-conductivity of 135 S m−1. By virtue of its unique architecture, the PCN6-based EDLC exhibits excellent energy storage properties. In EMIMBF4 electrolyte, it demonstrates an ultrahigh Cg of 157.8 F g−1 (57.4 F cm−3) at 20 A g−1, possessing a top-level rate capacity C20/0.05 of 86.7%. Simultaneously, its energy density can retain up to 67.1 W h kg−1 at a high power density of 17.5 kW kg−1. The ingenious structural design of PCNs can afford inspiration for constructing other 2D architecture carbon materials.