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Nb 2 O 5 /RGO Nanocomposite Modified Separators with Robust Polysulfide Traps and Catalytic Centers for Boosting Performance of Lithium–Sulfur Batteries
Author(s) -
Guo Pengqian,
Sun Kai,
Shang Xiaonan,
Liu Dequan,
Wang Yanrong,
Liu Qiming,
Fu Yujun,
He Deyan
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201902363
Subject(s) - nanocomposite , polysulfide , materials science , graphene , chemical engineering , catalysis , electrochemistry , nucleation , oxide , sulfur , separator (oil production) , redox , nanotechnology , electrode , chemistry , metallurgy , organic chemistry , electrolyte , thermodynamics , physics , engineering
Lithium–sulfur batteries (LSBs) have shown great potential for application in high‐density energy storage systems. However, the performance of LSBs is hindered by the shuttle effect and sluggish reaction kinetics of lithium polysulfides (LiPSs). Herein, heterostructual Nb 2 O 5 nanocrystals/reduced graphene oxide (Nb 2 O 5 /RGO) composites are introduced into LSBs through separator modification for boosting the electrochemical performance. The Nb 2 O 5 /RGO heterostructures are designed as chemical trappers and conversion accelerators of LiPSs. Originating from the strong chemical interactions between Nb 2 O 5 and LiPSs as well as the superior catalytic nature of Nb 2 O 5 , the Nb 2 O 5 /RGO nanocomposite possesses high trapping efficiency and efficient electrocatalytic activity to long‐chain LiPSs. The effective regulation of LiPSs conversion enables the LSBs enhanced redox kinetics and suppressed shuttle effect. Moreover, the Nb 2 O 5 /RGO nanocomposite has abundant sulfophilic sites and defective interfaces, which are beneficial for the nucleation and growth of Li 2 S, as evidenced by analysis of the cycled separators. As a result, LSBs with the Nb 2 O 5 /RGO‐modified separators exhibit excellent rate capability (816 mAh g −1 at 3 A g −1 ) and cyclic performance (628 mAh g −1 after 500 cycles). Remarkably, high specific capacity and stable cycling performance are demonstrated even at an elevated temperature of 50 °C or with higher sulfur loadings.