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Graphene Wrapped FeSe 2 Nano‐Microspheres with High Pseudocapacitive Contribution for Enhanced Na‐Ion Storage
Author(s) -
An Changsheng,
Yuan Yifei,
Zhang Bao,
Tang Linbo,
Xiao Bin,
He Zhenjiang,
Zheng Junchao,
Lu Jun
Publication year - 2019
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.201900356
Subject(s) - materials science , pseudocapacitance , graphene , chemical engineering , anode , nanotechnology , oxide , electrochemistry , faraday efficiency , hydrothermal circulation , ion , electrode , supercapacitor , engineering , chemistry , physics , quantum mechanics , metallurgy
Pseudocapacitance is a Faradaic process that involves surface or near surface redox reactions. Increasing the pseudocapacitive contribution is one of the most effective means to improve the rate performance of electrode materials. In this study, graphene oxide is used as a template to in situ synthesize burr globule‐like FeSe 2 /graphene hybrid (B‐FeSe 2 /G) using a facile one‐step hydrothermal method. Structural characterization demonstrates that graphene layers not only wrap the surfaces of FeSe 2 particles, but also stretch into the interior of these particles, as a result of which the unique nano‐microsphere structure is successfully established. When serving as anode material for Na‐ion batteries, B‐FeSe 2 /G hybrid displays high electrochemical performance in the voltage range of 0.5–2.9 V. The B‐FeSe 2 /G hybrid has high reversible capacity of 521.6 mAh·g −1 at 1.0 A g −1 . Meanwhile, after 400 cycles, high discharge capacity of 496.3 mAh g −1 is obtained at a rate of 2.5 A g −1 , with a high columbic efficiency of 96.6% and less than 1.0% loss of discharge capacity. Even at the ultrahigh rate of 10 A g −1 , a specific capacity of 316.8 mAh g −1 can be achieved. Kinetic analyses reveal that the excellent performance of the B‐FeSe 2 /G hybrid is largely attributed to the high pseudocapacitive contribution induced by the special nano‐micro structure.