Constructing Patch‐Ni‐Shelled Pt@Ni Nanoparticles within Confined Nanoreactors for Catalytic Oxidation of Insoluble Polysulfides in Li‐S Batteries. Issue 34 (17th June 2019)

• Record Type: Journal Article
• Authors: Liu, Yang; Kou, Wei; Li, Xiangcun; Huang, Chuqing; Shui, Ruobing; He, Gaohong
• Is Part Of: Small. Volume 15:Issue 34(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-06-17
• Subjects: catalytic oxidation -- lithium‐sulfur batteries -- nanoreactors -- polysulfide conversion -- synergic effects; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.201902431
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: 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 Li2 S2 /Li2 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 Li2 S to polysulfides. The Li2 S bound to adjacent Pt sites reacts with abundant ‐S‐Li species and then releases the Pt sites for the next round of reactions. Abstract : A Pt@Ni core‐shell catalyst with a synergic effect in confined nanoreactors shows dual functions for catalytic oxidation of insoluble products to soluble polysulfides by effectively reducing the energy barrier with strong adsorption. Electronic migration from Ni to Pt becomes a driving force to activate Li2 S molecules to form Ni‐S‐Li, the presence of ‐S‐Li is more active to oxidize Li2 S2 /Li2 S to polysulfides.