Solvent‐Exchange Strategy toward Aqueous Dispersible MoS2 Nanosheets and Their Nitrogen‐Rich Carbon Sphere Nanocomposites for Efficient Lithium/Sodium Ion Storage

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 15; no. 45; pp. e1903816 - n/a
• Main Authors: Wang, Yufeng, Wang, Kai, Zhang, Chao, Zhu, Jixin, Xu, Jingsan, Liu, Tianxi
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.11.2019
• Subjects: Anodes; Boiling points; Carbon; Discharge; Dispersion; Electrode materials; Electron transport; Ethanol; Exchanging; Ion storage; liquid‐phase exfoliation; Lithium; lithium/sodium ion batteries; Molybdenum disulfide; Nanocomposites; Nanosheets; Nanotechnology; Nitrogen; nitrogen‐rich carbon; Polypyrroles; Pyrolysis; Sodium-ion batteries; Solvents; solvent‐exchange strategies; Strategy; Structural integrity
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.201903816

Major challenges in developing 2D transition‐metal disulfides (TMDs) as anode materials for lithium/sodium ion batteries (LIBs/SIBs) lie in rational design and targeted synthesis of TMD‐based nanocomposite structures with precisely controlled ion and electron transport. Herein, a general and scalable solvent‐exchange strategy is presented for uniform dispersion of few‐layer MoS2 (f‐MoS2) from high‐boiling‐point solvents (N‐methyl‐2‐pyrrolidone (NMP), N,N‐dimethyl formaldehyde (DMF), etc.) into low‐boiling‐point solvents (water, ethanol, etc.). The solvent‐exchange strategy dramatically simplifies high‐yield production of dispersible MoS2 nanosheets as well as facilitates subsequent decoration of MoS2 for various applications. As a demonstration, MoS2‐decorated nitrogen‐rich carbon spheres (MoS2‐NCS) are prepared via in situ growth of polypyrrole and subsequent pyrolysis. Benefiting from its ultrathin feature, largely exposed active surface, highly conductive framework and excellent structural integrity, the 2D core–shell architecture of MoS2‐NCS exhibits an outstanding reversible capacity and excellent cycling performance, achieving high initial discharge capacity of 1087.5 and 508.6 mA h g−1 at 0.1 A g−1, capacity retentions of 95.6% and 94.2% after 500 and 250 charge/discharge cycles at 1 A g−1, for lithium/sodium ion storages, respectively. A solvent‐exchange strategy is presented for efficient exfoliation and uniform dispersion of few‐layer MoS2 nanosheets in low‐boiling‐point solvents, which facilitates further decorations of nitrogen‐rich carbon spheres for significantly enhanced Li/Na ion storage.