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Constructing Patch‐Ni‐Shelled Pt@Ni Nanoparticles within Confined Nanoreactors for Catalytic Oxidation of Insoluble Polysulfides in Li‐S Batteries
Author(s) -
Liu Yang,
Kou Wei,
Li Xiangcun,
Huang Chuqing,
Shui Ruobing,
He Gaohong
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.201902431
Subject(s) - bimetallic strip , catalysis , polysulfide , nanodot , nanoreactor , chemical engineering , nanoparticle , chemistry , redox , materials science , electron transfer , inorganic chemistry , nanotechnology , photochemistry , electrolyte , electrode , organic chemistry , engineering
Reducing the deposit of discharge products and suppressing the polysulfide shuttle are critical to enhancing reaction kinetics in Li‐S batteries. Herein, a Pt@Ni core–shell bimetallic catalyst with a patch‐like or complete Ni shell based on a confined catalysis reaction in porous carbon spheres is reported. The Pt nanodots can effectively direct and catalyze in situ reduction of Ni 2+ ions to form core–shell catalysts with a seamless interface that facilitates the charge transfer between the two metals. Thus, the bimetallic catalysts offer a synergic effect on catalyzing reactions, which shows dual functions for catalytic oxidation of insoluble polysulfides to soluble polysulfides by effectively reducing the energy barrier with simultaneous strong adsorption, ensuring a high reversible capacity and cycling stability. A novel process based on the Pt@Ni core–shell bimetallic catalyst with a patch‐like Ni shell is proposed: electronic migration from Ni to Pt forces Ni to activate Li 2 S 2 /Li 2 S molecules by promoting the transformation of Li‐S‐Li to Ni‐S‐Li, consequently releasing Li + and free electrons, simultaneously enhancing protonic/electronic conductivity. The presence of the intermediate state Ni‐S‐Li is more active to oxidize Li 2 S to polysulfides. The Li 2 S bound to adjacent Pt sites reacts with abundant ‐S‐Li species and then releases the Pt sites for the next round of reactions.