3D Ferroconcrete‐Like Aminated Carbon Nanotubes Network Anchoring Sulfur for Advanced Lithium–Sulfur Battery

Abstract

To address the serious capacity fading in lithium–sulfur batteries, a 3D ferroconcrete‐like aminated carbon nanotubes network with polyaniline coating as an effective sulfur host to contain polysulfide dissolution is presented here. In this composite, the cross‐linked aminated carbon nanotubes framework provides a fast charge transport pathway and enhancement in the reaction kinetics of the active material to greatly improve the rate capability and sulfur utilization. The ethylenediamine moieties provide strong adhesion of polar discharge products to nonpolar carbon surfaces and thus efficiently prevent polysulfide dissolution to improve the cycle stability, confirmed by density functional theory calculations. The outside polyaniline layers structurally restrain polysulfides to prevent the shuttle effect and active material loss. Benefiting from these advantages, the synthesized composite exhibits a high initial capacity of 1215 mAh g−1 and a capacity of 975 mAh g−1 after 200 cycles at 0.2 C. Even after 200 cycles at 0.5 C, a capacity of 735 mAh g−1 can be maintained, among the best performance reported. The strategy in this work can shed some light on modifying nonpolar carbon surfaces via the amination process to chemically attach sulfur species for high‐performance lithium–sulfur batteries.

Host Materials Anchoring Polysulfides in Li–S Batteries Reviewed

“…Yan et al used EDA to modify CNT networks and then covered these with polyaniline, forming a 3D ferroconcrete-like architecture (P@E-CNT). [132] The prepared P@E-CNT/S composite preserved the initial morphology (Figure 6e). The EDA moieties were very effective to anchor the polar discharge products at nonpolar carbon, hence efficiently preventing polysulfides from dissolving into the electrolyte.…”

“…(e,f) Reproduced with permission. [132] Copyright 2018, Wiley-VCH. space to accommodate sulfur, which is beneficial to the polysulfide confinement.…”

Chemical Confinement and Utility of Lithium Polysulfides in Lithium Sulfur Batteries

“…For instance, functionalizing reduced graphene oxide with ethylene diamine existing amine groups which served as chemical anchoring sites of LiPS by providing lone pair of electrons to coordinate with lithium improved the cycling stability of Li–S batteries . Yan et al modified CNT network with ethylenediamine moieties by nucleophilic attack on several types of carbon atom which connected with oxygen containing functional groups ( Figure a) . Though the polyaniline consisting of nitrogen‐containing groups was coated as an outside layer to encapsulate the sulfur composite according to the synthesis process, the grafting of ethylenediamine moieties on the surface of CNT had much more effect on the cycling performance of Li–S batteries.…”

“…a) Synthesis process of the polyaniline (PANI) coating ethylenediamine (EDA)‐modified carbon nanotubes/sulfur. Reproduced with permission . Copyright 2018, Wiley‐VCH.…”

Embedding tin disulfide nanoparticles in two-dimensional porous carbon nanosheet interlayers for fast-charging lithium-sulfur batteries

“…To overcome these shortcomings, carbon materials like carbon nanotubes [11], carbon nanofibers [12], hollow carbon spheres [13], and graphene [14,15] have been highlighted for their excellent electrical conductivity and physical adsorption with polysulfides [16,17]. Among these materials, two-dimensional (2D) layered carbon materials have been developed as new energy storage materials.…”