Highly Efficient Retention of Polysulfides in “Sea Urchin”-Like Carbon Nanotube/Nanopolyhedra Superstructures as Cathode Material for Ultralong-Life Lithium–Sulfur Batteries

Abstract

Despite high theoretical energy density, the practical deployment of lithium-sulfur (Li-S) batteries is still not implemented because of the severe capacity decay caused by polysulfide shuttling and the poor rate capability induced by low electrical conductivity of sulfur. Herein, we report a novel sulfur host material based on "sea urchin"-like cobalt nanoparticle embedded and nitrogen-doped carbon nanotube/nanopolyhedra (Co-NCNT/NP) superstructures for Li-S batteries. The hierarchical micromesopores in Co-NCNT/NP can allow efficient impregnation of sulfur and block diffusion of soluble polysulfides by physical confinement, and the incorporation of embedded Co nanoparticles and nitrogen doping (∼4.6 at. %) can synergistically improve the adsorption of polysulfides, as evidenced by beaker cell tests. Moreover, the conductive networks of Co-NCNT/NP interconnected by nitrogen-doped carbon nanotubes (NCNTs) can facilitate electron transport and electrolyte infiltration. Therefore, the specific capacity, rate capability, and cycle stability of Li-S batteries are significantly enhanced. As a result, the Co-NCNT/NP based cathode (loaded with 80 wt % sulfur) delivers a high discharge capacity of 1240 mAh g after 100 cycles at 0.1 C (based on the weight of sulfur), high rate capacity (755 mAh g at 2.0 C), and ultralong cycling life (a very low capacity decay of 0.026% per cycle over 1500 cycles at 1.0 C). Remarkably, the composite cathode with high areal sulfur loading of 3.2 mg cm shows high rate capacities and stable cycling performance over 200 cycles.

In Situ Assembly of 2D Conductive Vanadium Disulfide with Graphene as a High‐Sulfur‐Loading Host for Lithium–Sulfur Batteries

“…When cycled at 0.2 C, an initial capacity of 1015 mAh g −1 is attained for the 5.0 mg cm −2 electrode, corresponding to an areal capacity of 5.1 mAh cm −2 . The areal specific capacities under high sulfur loadings in this work are remarkable among the reported hybrid sulfur hosts (Figure 6d; Figure S17, Supporting Information), [17,20,25,[43][44][45][46][47] especially for the cycling at a high current density (1 C), where there has been a limited number of studies (Figure 6d). Further, the cycling stabilities of our hybrid electrodes could be well maintained even at high current densities.…”

Porous Carbon Nanosheets Prepared from Plastic Wastes for Supercapacitors

“…The amide carbonyl groups of PVP can be coordinated with Co and Zn ions 25,26 which promote the growth of CoZn-ZIF crystals on Mg(OH) 2 sheets and the product termed Mg(OH) 2 @-CoZn-ZIFs. When the mixture of Mg(OH) 2 @CoZn-ZIFs and PS is heated to 900°C, Zn element evaporates to generate more micro-or mesopores in the N-PCNs 25,27 and Co species work as catalysts to promote the degree of graphitization of N-PCNs. Furthermore, nitrogen is introduced into the carbon framework of N-PCNs through pyrolysis of imidazole ligands.…”

Highly Dispersed Cobalt Clusters in Nitrogen‐Doped Porous Carbon Enable Multiple Effects for High‐Performance Li–S Battery

“…However, the long battery life was obtained only at a low sulfur content (30 wt%) because of the special pore structure and electrical conductivity. Thus, more studies have focused on applying multifunctional pyrolytic carbon materials derived from MOF as host structures for Li–S batteries. For instance, Li et al reported that a new type of ZIF67‐derived sulfur host containing cobalt and N‐doped graphitic carbon exhibited an outstanding high rate response of up to 5C.…”