Functional Differentiation of Three Pores for Effective Sulfur Confinement in Li–S Battery

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 14; no. 11; pp. e1703279 - n/a
• Main Authors: Wang, Qian, Yang, Minghui, Wang, Zhen‐Bo, Li, Chao, Gu, Da‐Ming
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.03.2018
• Subjects: Carbon; Cycles; Decay rate; functional separation of three pores; high cyclic stability under high loading; in situ oxidation preparation; Lithium; Nanotechnology; Oxidation; Porosity; rambutan‐shaped sulfur/carbon composites; self‐assembled ZnS precursors; Sulfur; Synthesis; Zinc coatings; Zinc sulfide; self-assembled ZnS precursors; functional separation of three pores; rambutan-shaped sulfur/carbon composites; high cyclic stability under high loading; in situ oxidation preparation
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201703279

Shuttle effect of the dissolved intermediates is regarded as the primary cause that leads to fast capacity degradation of Li–S battery. Herein, a microporous carbon‐coated sulfur composite with novel rambutan shape (R‐S@MPC) is synthesized from microporous carbon‐coated rambutan‐like zinc sulfide (R‐ZnS@MPC), via an in situ oxidation process. The R‐ZnS is employed as both template and sulfur precursor. The carbon frame of R‐S@MPC composite possesses three kinds of pores that are distinctly separated from each other in space and are endowed with the exclusive functions. The central macropore serves as buffer pool to accommodate the dissolved lithium polysulfides (LPSs) and volumetric variation during cycling. The marginal straight‐through mesoporous, connected with the central macropore, takes the responsibility of sulfur storage. The micropores, evenly distributed in the outer carbon shell of the as‐synthesized R‐S@MPC, enable the blockage of LPSs. These pores are expected to perform their respective single function, and collaborate synergistically to suppress the sulfur loss. Therefore, it delivers an outstanding cycling stability, decay rate of 0.013% cycle−1 after 500 cycles at 1 C, when the sulfur loading is kept at 4 mg cm−2. A rambutan‐shaped microporous carbon‐coated sulfur composite is synthesized from the self‐assembled ZnS precursor, through the in situ oxidation process. The functions of the three pores in the unique framework are divided and singularized, macropores for accommodation, mesopores for storage, and micropores for blockage. The excellent cycling stability is exactly originated from the functional separation and cooperation of the three pores.