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Microemulsion Assisted Assembly of 3D Porous S/Graphene@g‐C 3 N 4 Hybrid Sponge as Free‐Standing Cathodes for High Energy Density Li–S Batteries
Author(s) -
Zhang Juan,
Li JinYi,
Wang WenPeng,
Zhang XingHao,
Tan XingHua,
Chu WeiGuo,
Guo YuGuo
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201702839
Subject(s) - materials science , cathode , microemulsion , chemical engineering , anode , graphene , porosity , sulfur , nanotechnology , electrode , composite material , chemistry , pulmonary surfactant , engineering , metallurgy
Abstract A 3D porous sulfur/graphene@g‐C 3 N 4 (S/GCN) hybrid sponge, which can be directly applied as a free‐standing cathode for Li–S batteries, is realized via a microemulsion assisted assembly approach. In this strategy, the interior oil emulsion droplets serve as soft templates to form pores to accommodate sulfur and the hydrophilic GCN stacks around oil droplets to assemble into a crosslinked 3D network. Through this microemulsion encapsulation route, S/GCN cathodes with a sulfur loading as high as 82 wt% can be achieved. Furthermore, the enriched N‐sites in GCN macropores offer numerous adhesion sites for polysulfides, realizing a “physical‐chemical” dual‐confinement for polysulfides from diffusion. Moreover, the robust and highly porous 3D graphene frameworks render efficient electron/Li + transport pathways for fast kinetics as well as good structure integrity. Consequently, in comparison to the conventional G‐sponge/Li 2 S n catholyte system, S/GCN delivers a higher specific capacity, superior high‐rate capability (612 mA h g −1 at 10 C), and alleviated anode corrosion issues. Particularly, an energy density as high as 1493 W h kg −1 (calculated on the total weight of the cathode) and an extremely low capacity fading rate of 0.017% per cycle over 800 cycles at 0.3 C are achieved.