A Transmetalation Synthetic Strategy to Engineer Atomically Dispersed MnN₂O₂ Electrocatalytic Centers Driving High‐Performance LiS Battery

Abstract

Sluggish sulfur redox reaction (SROR) kinetics accompanying lithium polysulfides (LiPSs) shuttle effect becomes a stumbling block for commercial application of LiS battery. High‐efficient single atom catalysts (SACs) are desired to improve the SROR conversion capability; however, the sparse active sites as well as partial sites encapsulated in bulk‐phase are fatal to the catalytic performance. Herein, high loading (5.02 wt.%) atomically dispersed manganese sites (MnSA) on hollow nitrogen‐doped carbonaceous support (HNC) are realized for the MnSA@HNC SAC by a facile transmetalation synthetic strategy. The thin‐walled hollow structure (≈12 nm) anchoring the unique trans‐MnN2O2 sites of MnSA@HNC provides a shuttle buffer zone and catalytic conversion site for LiPSs. Both electrochemical measurement and theoretical calculation indicate that the MnSA@HNC with abundant trans‐MnN2O2 sites have extremely high bidirectional SROR catalytic activity. The assembled LiS battery based on the MnSA@HNC modified separator can deliver a large specific capacity of 1422 mAh g−1 at 0.1 C and stable cycling over 1400 cycles with an ultralow decay rate of 0.033% per cycle at 1 C. More impressively, a flexible pouch cell on account of the MnSA@HNC modified separator may release a high initial specific capacity of 1192 mAh g−1 at 0.1 C and uninterruptedly work after the bending‐unbending processes.

Multi-heterostructured MXene/NiS2/Co3S4 with S-Vacancies to Promote Polysulfide Conversion in Lithium–Sulfur Batteries

“…In addition, based on the corresponding Tafel region on the LSV curves, the slopes of MXene/NiS 2 , MXene/Co 3 S 4 and MXene/NiS 2 /Co 3 S 4 are determined to be 1734, 904, and 344 mV dec –1 , respectively (Figure e). The smallest slope of MXene/NiS 2 /Co 3 S 4 also manifests its best electrocatalytic activity among the three catalysts, which is attributable to the following aspects . First, the presence of the built-in electric field can accelerate the transfer of charges and ions.…”

“…The smallest slope of MXene/ NiS 2 /Co 3 S 4 also manifests its best electrocatalytic activity among the three catalysts, which is attributable to the following aspects. 32 First, the presence of the built-in electric field can accelerate the transfer of charges and ions. Second, the abundant vacancies and heterostructures at the interface provide adequate active sites to participate in the catalytic conversion.…”

High-Entropy Metal Oxide-Coated Carbon Cloth as Catalysts for Long-Life Li–S Batteries

“…Peak A and peak B emerge in the cathodic scanning, which can be ascribed as the transformation of S into soluble polysulfides and finally the precipitation of Li 2 S, while peak C in the anodic side means the formation of sulfur by the oxidation of lithium sulfide. − It should be noted that the voltage difference between peak C and peak B for the cell with CC/HEO is 0.40 V while for the cell with CC, it is 0.45 V. Besides, the current density is larger for the cell with CC/HEO than that of CC. It can be explained as the lower polarization of the cell with CC/HEO. − Figure b shows the column of the Tafel slope value derived from Figure S7. It can be seen that the Tafel slope for the cell with CC/HEO is smaller, which matches well with the conclusion in Figure a.…”

Nonmetallic‐Bonding Fe–Mn Diatomic Pairs Anchored on Hollow Carbonaceous Nanodisks for High‐Performance Li–S Battery

“…[56] As shown in Figure 8g, the dissociation energy of Li 2 S on these substrates is much greater than the Li ion migration barrier, indicating that the Li-S bond breaking is a rate-limiting step in the decomposition process. [37] Compared with Fe@FeN 4 (1.22 eV) and Mn@MnN 4 (1.27 eV), the dissociation energy barriers of Li 2 S on Fe@FeN 4 /MnN 4 and Mn@FeN 4 /MnN 4 are lower to 1.11 and 1.14 eV, implying the improved transformation kinetics of Li 2 S on both metal sites. The DFT calculation shows that the enhanced bidirection catalytic conversion of LiPSs reduction and Li 2 S dissociation corresponding to the discharge and charging processes, respectively, improves the utilization of sulfur substances, which matches the greatly improved electrochemical performance of Li-S battery.…”

“…Subsequently, polydopamine (PDA) coated 𝛼-Fe 2 O 3 /PDA precursor and MnCl 2 •4H 2 O were placed in tube furnace separately and MnCl 2 •4H 2 O was placed in upstream to introduce manganese into the PDA precursor and corrode the 𝛼-Fe 2 O 3 template. [37] After high temperature pyrolysis treatment, as shown in Figure S2a in the Supporting Information, the 𝛼-Fe 2 O 3 was reduced to a mixture of different valence compounds (marked as FeO x , 0 ≤ x ≤ 3), and the TEM images of intermediate FeO x /FeMnDA@NC present the disappearance of partial FeO x indicating that Cl − reacted with FeO x to release gaseous Fe species under the high temperature (Figure S2b,c, Supporting Information). PDA-derived nitrogen-doped carbon captured the gaseous Fe and Mn species forming atomically dispersed Fe/Mn-N x active sites during pyrolysis process.…”