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Abstract Porous carbon plays a significant role in all‐solid‐state lithium‐sulfur batteries (ASSLSBs) to enhance the electronic conductivity of sulfur. However, the conventional porous carbon used in cell with liquid electrolyte exhibits low efficiency in ASSLSBs because the immobile solid electrolyte (SE) cannot reach sulfur confined in the deep pores. The structure and distribution of pores in carbon highly impact the electrochemical performance of ASSLSBs. Herein, a N‐doped carbon fiber with micropores located only at the surface with an ultrahigh surface area of 1519 m2 g–1is designed. As the porous layer is only on the surface, the sulfur hosted in the pores can effectively contact SE; meanwhile the dense core provides excellent electrical conductivity. Therefore, this structurally designed carbon fiber enhances both electron and ion accessibilities, promotes charge transfer, and thus dramatically improves the reaction kinetic in the ASSLSBs and boosts sulfur utilization. Compared to the vapor grown carbon fibers, the ASSLSBs using PAN‐derived porous carbon fibers exhibit three times enhancement in the initial capacity of 1166 mAh g–1at C/20. An exceedingly cycling stability of 710 mAh g–1is maintained after 220 cycles at C/10, and satisfactory rate capability of 889 mAh g–1at C/2 is achieved.
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Two‐Dimensional Arrays of Transition Metal Nitride Nanocrystals
Abstract The synthesis of low‐dimensional transition metal nitride (TMN) nanomaterials is developing rapidly, as their fundamental properties, such as high electrical conductivity, lead to many important applications. However, TMN nanostructures synthesized by traditional strategies do not allow for maximum conductivity and accessibility of active sites simultaneously, which is a crucial factor for many applications in plasmonics, energy storage, sensing, and so on. Unique interconnected two‐dimensional (2D) arrays of few‐nanometer TMN nanocrystals not only having electronic conductivity in‐plane, but also allowing transport of ions and electrolyte through the porous nanosheets, which are obtained by topochemical synthesis on the surface of a salt template, are reported. As a demonstration of their application in a lithium–sulfur battery, it is shown that 2D arrays of several nitrides can achieve a high initial capacity of >1000 mAh g−1at 0.2 C and only about 13% degradation over 1000 cycles at 1 C under a high areal sulfur loading (>5 mg cm−2).
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- Award ID(s):
- 1719875
- PAR ID:
- 10375518
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 31
- Issue:
- 33
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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