Sub-nanometric Manganous Oxide Clusters in Nitrogen Doped Mesoporous Carbon Nanosheets for High-Performance Lithium–Sulfur Batteries

Abstract

The greatest challenge for lithium−sulfur (Li−S) batteries application is the development of cathode hosts to address the low conductivity, huge volume change, and shuttling effect of sulfur or lithium polysulfides (LiPs). Herein, we demonstrate a composite host to circumvent these problems by confining sub-nanometric manganous oxide clusters (MOCs) in nitrogen doped mesoporous carbon nanosheets. The atomic structure of MOCs is well-characterized and optimized via the extended X-ray absorption fine structure analysis and density functional theory (DFT) calculations. Benefiting from the unique design, the assembled Li−S battery displays remarkable electrochemical performances including a high reversible capacity (990 mAh g −1 after 100 cycles at 0.2 A g −1 ) and a superior cycle life (60% retention over 250 cycles at 2 A g −1 ). Both the experimental results and DFT calculations demonstrate that the well-dispersed MOCs could significantly promote the chemisorption of LiPs, thus greatly improving the capacity and rate performance.

Implanting Cobalt Atom Clusters within Nitrogen‐Doped Carbon Network as Highly Stable Cathode for Lithium–Sulfur Batteries

“…The characteristic peaks of elemental sulfur were observed in the XRD pattern of S@Co/PNC (Figure S10, Supporting Information), indicating that the crystalline sulfur was successfully loaded into the carbon matrix of S@Co/PNC. [ 6 ]…”

“…[ 4 ] For instance, mesoporous carbon was developed to contain a sulfur cathode, and the mesoporous materials could not only improve the contact between insulating sulfur or lithium sulfide and the carbon network and facilitate the ion/electron transfer but also reduce the volume change and maintain good structural durability to achieve long‐term cycling stability. [ 5 ] A variety of mesoporous carbons have been developed as scaffolds to stabilize the sulfur cathode for lithium–sulfur batteries, such as bimodal mesoporous carbon, [ 6 ] mesoporous carbon spheres, [ 7 ] and bioderived carbonaceous mesoporous carbons. [ 8 ] Thus far, based on the mesoporous carbon acting as a scaffold for hosting sulfur, the two problems of volume change and poor conductivity of sulfur cathode can be efficiently mitigated for Li–S batteries.…”

“…Currently, nonmetallic heteroatoms, which have higher electronegativity than carbon, are used to dope into the carbon structure to enhance the polarity of mesoporous carbons. [ 6,12 ] Compared to metal compounds, nonmetallic dopants typically have weaker polarity and cannot provide sufficient absorptivity to contain polysulfides. [ 13 ] However, metal‐based species with good polarity are often supported by nanoparticles.…”

A review of size engineering-enabled electrocatalysts for Li–S chemistry

“…(e) rate capabilities at various current densities of the S/rGO@mC-MnO-800 assembled cells. 46 Copyright 2020, American Chemical Society. (f, g) SEM and HR-TEM of N-PC@uCo/S.…”

Bimetal CoNi Active Sites on Mesoporous Carbon Nanosheets to Kinetically Boost Lithium−Sulfur Batteries

“…[1][2][3][4] Lithium−sulfur batteries (LSBs) have attracted great research interests due to their high theoretical specific capacity (1675 mAh g −1 ), low cost, and nontoxicity. [5][6][7] But it is limited by the insulation of sulfur, the volume expansion during discharging and the shuttle effect caused by lithium polysulfides dissolved in electrolytes. [8][9][10] The soluble polysulfide intermediates diffuse between the cathode and anode during charge/discharge process, leading to the rapid decay of batteries' cycling life.…”