Multifunctional SnO2 QDs/MXene Heterostructures as Laminar Interlayers for Improved Polysulfide Conversion and Lithium Plating Behavior

• Published in: Nano-micro letters Vol. 16; no. 1; pp. 229 - 14
• Main Authors: Deng, Shungui, Sun, Weiwei, Tang, Jiawei, Jafarpour, Mohammad, Nüesch, Frank, Heier, Jakob, Zhang, Chuanfang
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 01.12.2024; Springer Nature B.V; SpringerOpen
• Subjects: Adsorption; Catalysis; Catalytic converters; Commercialization; Cycles; Electrochemical analysis; Electrolytic cells; Engineering; Heterogeneous catalysis; Heterostructure; Heterostructures; Interlayers; Lithium; Lithium dendrites; Lithium sulfur batteries; Lithium–sulfur battery; MXenes; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Polysulfides; Quantum dots; Reaction kinetics; Redox kinetics; Separators; Stability; Sulfur; Tin dioxide; Transition metals; Heterostructure; Heterogeneous catalysis; Redox kinetics; Lithium dendrites; Lithium–sulfur battery
• ISSN: 2311-6706; 2150-5551; 2150-5551
• DOI: 10.1007/s40820-024-01446-w

Highlights The interfacing between SnO 2 and MXene alters electronic structures, shifting the d -band center in transition metals, enhancing catalytic efficiency by reducing electron filling in antibonding orbitals. A binder-free, ultrathin, laminar heterostructured interlayer on polypropylene separator is demonstrated. The ionic sieving mechanism and efficient adsorption–catalysis process enable deeper charge/discharge cycle and improved stability. The improved catalytic conversion and suppressed lithium dendrites formation enable a high loading of 7.5 mg cm −2 and an initial area capacity of 7.6 mAh cm −2 . Poor cycling stability in lithium–sulfur (Li–S) batteries necessitates advanced electrode/electrolyte design and innovative interlayer architectures. Heterogeneous catalysis has emerged as a promising approach, leveraging the adsorption and catalytic performance on lithium polysulfides (LiPSs) to inhibit LiPSs shuttling and improve redox kinetics. In this study, we report an ultrathin and laminar SnO 2 @MXene heterostructure interlayer (SnO 2 @MX), where SnO 2 quantum dots (QDs) are uniformly distributed across the MXene layer. The combined structure of SnO 2 QDs and MXene, along with the creation of numerous active boundary sites with coordination electron environments, plays a critical role in manipulating the catalytic kinetics of sulfur species. The Li–S cell with the SnO 2 @MX-modified separator not only demonstrates superior electrochemical performance compared to cells with a bare separator but also induces homogeneous Li deposition during cycling. As a result, an areal capacity of 7.6 mAh cm −2 under a sulfur loading of 7.5 mg cm −2 and a high stability over 500 cycles are achieved. Our work demonstrates a feasible strategy of utilizing a laminar separator interlayer for advanced Li–S batteries awaiting commercialization and may shed light on the understanding of heterostructure catalysis with enhanced reaction kinetics.