Biotemplating Growth of Nepenthes-like N-Doped Graphene as a Bifunctional Polysulfide Scavenger for Li–S Batteries

Abstract

The practical application of lithium-sulfur (Li-S) batteries is hindered by their poor cycling stabilities that primarily stem from the "shuttle" of dissolved lithium polysulfides. Here, we develop a nepenthes-like N-doped hierarchical graphene (NHG)-based separator to realize an efficient polysulfide scavenger for Li-S batteries. The 3D textural porous NHG architectures are realized by our designed biotemplating chemical vapor deposition (CVD) approach via the employment of naturally abundant diatomite as the growth substrate. Benefiting from the high surface area, devious inner-channel structure, and abundant nitrogen doping of CVD-grown NHG frameworks, the derived separator favorably synergizes bifunctionality of physical confinement and chemical immobilization toward polysulfides, accompanied by smooth lithium ion diffusions. Accordingly, the batteries with the NHG-based separator delivers an initial capacity of 868 mAh g with an average capacity decay of only 0.067% per cycle at 2 C for 800 cycles. A capacity of 805 mAh g can further be achieved at a high sulfur loading of ∼7.2 mg cm. The present study demonstrates the potential in constructing high-energy and long-life Li-S batteries upon separator modification.

Rationalizing Electrocatalysis of Li–S Chemistry by Mediator Design: Progress and Prospects

“…With these advantages, the S/VN cathode delivered an impressive areal capacity of 5.81 mAh cm −2 with a high sulfur loading of 5.4 mg cm −2 and showed a capacity retention of 74.3% at 0.5 C after 200 cycles. Li et al also developed a nepenthes‐like N‐doped hierarchical graphene (NHG) via direct chemical vapor deposition (CVD) approach by the employment of naturally abundant diatomite as the growth template (Figure b) . Benefiting from the conformal growth of graphene on diatomite, the nepenthes‐like NHG presented 3D textural porous structure and light‐weight features.…”

“…b) N‐doped hierarchical graphene. Reproduced with permission . Copyright 2018, American Chemical Society.…”

Microporous Carbon Nanofibers Derived from Poly(acrylonitrile‐co‐acrylic acid) for High‐Performance Supercapacitors

“…As a result, some of the nitrogen atoms in the CNF are converted to gas after activation, and this leads to a much lower nitrogen content of 0.8 % for ACNF‐12. As the AA fraction in the copolymer changes, the oxygen content and bonding mode of the obtained CNFs varies, as observed in the C 1s XP spectrum of the material (Figure c).The C 1s XP spectrum can be split into five separate component peaks, that is, C1 for C−C, C2 for C−OH/C‐O‐C, C3 for C=O, C4 for COOH, and C5 for oscillatory satellite peaks, respectively . The O 1s XP spectra of all of the materials can be split to three independent peaks, corresponding to OH, C−O, and C=O (Figure S3 in the Supporting Information).…”

Two‐Dimensional Material‐Functionalized Separators for High‐Energy‐Density Metal–Sulfur and Metal‐Based Batteries

“…f) Schematic illustration of the suppression of PS shuttling in an LSB using an N‐doped graphene‐modified separator. Reproduced with permission . Copyright 2017, American Chemical Society.…”

“…The lightweight separator showed excellent PS‐entrapping capability, which contributed to a capacity retention of 81.2 % after 400 cycles at 0.5 C for a cathode with sulfur content of 70 wt % and loading of 6.0 mg cm −2 (Figure c, d) . Constructing 2 D N‐doped graphene into 3 D structure with rich interchannels can further enhance the permselectivity of Li ions versus polysulfides and the trapping capability of lithium PSs (LiPSs) . The role of N doping was investigated by DFT simulations (Figure e).…”