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Core-shell structured sulfur composite nanoparticles (NPs) and their various derivatives have been widely inves- tigated as a promising cathode material for Li-S batteries (LSBs) thanks to their unique features in suppressing the lithium polysulfides shuttle effect, accommodating the sulfur electrode volume change, and providing abundant electrochemically active sites. The commonly used infiltration strategy falls short in producing a near ideal core- shell structure. Accordingly, the strategy of encapsulation, in which the prefabricated sulfur or sulfur precursor nanocore is encapsulated by a subsequently formed host shell has attracted broad interest, and this technique has significantly accelerated the LSB development. To advance the state of the art in producing encapsulated sulfur NPs, it becomes necessary to systematically survey the past relevant works and sum up research gaps. This review first takes an excursion to the infiltration strategy to highlight its limitations, followed by surveys on studies of synthesizing sulfur NPs, encapsulating sulfur NPs, and producing encapsulated sulfur NPs from metal sulfides. The strengths and weaknesses of each method, the resulted NPs, their electrochemical properties and the associated LSB performances are particularly emphasized. The rationales to design and the results of applying structural derivatives of the conventional core-shell configuration are then assessed. The encapsulated sulfur NPs applied in aqueous batteries are also discussed. This comprehensive review on sulfur encapsulation is concluded by a summary on further challenges and opportunities as well as our perspectives on possible future research directions, towards fundamental understanding and practical development of encapsulated sulfur NP-based LSB technology.
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A Programmable Nanoparticle Conversion Pathway to Monodisperse Polyelemental High Entropy Alloy, Intermetallic, and Multiphase Nanoparticles
Abstract Polyelemental nanoparticles (PE NPs), those consisting of four or more elements, exhibit unique properties from synergistic compositional effects. Examples include high entropy alloys, high entropy intermetallics, and multiphase types, including Janus and core‐shell architectures. Although colloidal syntheses offer excellent structural control for mono‐ and bi‐elemental compositions, achieving the same control for PE NPs remains challenging. Here, this challenge is addressed with a NP conversion strategy wherein different types of PE NPs – including high entropy alloy, high entropy intermetallic, and multiphase Janus nanoparticles – are achieved through thermal transformation of readily synthesized colloidal core‐shell NPs. Through systematic variations in stoichiometry and metal identity to the core‐shell precursor NPs, along with atomistic simulations that probe phase stabilities, we deduce that the final mixing states of the various NPs are governed by the balance between the enthalpy and entropy of mixing. Moreover, our annealing method allows us to trap NPs at intermediate states of mixing, creating distinct surface ensembles that were evaluated as catalysts for the hydrogen evolution reaction. This study is the first, to our knowledge, to report colloidally derived precursor NPs enabling the synthesis of all types of PE NPs in a single process. This NP conversion strategy offers a general route to diverse PE NPs.
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- Award ID(s):
- 2203349
- PAR ID:
- 10587505
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 64
- Issue:
- 26
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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