Electrostatic Potential-Induced Co–N₄ Active Centers in a 2D Conductive Metal–Organic Framework for High-Performance Lithium–Sulfur Batteries

Abstract

The use of single-atom catalysts is a promising approach to solve the issues of polysulfide shuttle and sluggish conversion chemistry in lithium−sulfur (Li−S) batteries. However, a single-atom catalyst usually contains a low content of active centers because more metal ions lead to generation of aggregation or the formation of nonatomic catalysts. Herein, a 2D conductive metal−organic framework [Co 3 (HITP) 2 ] with abundant and periodic Co−N 4 centers was decorated on carbon fiber paper as a functional interlayer for advanced Li−S batteries. The Co 3 (HITP) 2 -decorated interlayer exhibits a chemical anchoring effect and facilitates conversion kinetics, thus effectively restraining the polysulfide shuttle effect. Density functional theory calculations demonstrate that the Co−N 4 centers in Co 3 (HITP) 2 feature more intense electron density and more negative electrostatic potential distribution than those in the carbon matrix as the singleatom catalyst, thereby promoting the electrochemical performance due to the lower reaction Gibbs free energies and decomposition energy barriers. As a result, the optimized batteries deliver a high rate capacity of over 400 mA h g −1 at 4 C current and a satisfying capacity decay rate of 0.028% per cycle over 1000 cycles at 1 C. The designed Co 3 (HITP) 2 -decorated interlayer was used to prepare one of the most advanced Li−S batteries with excellent performance (reversible capacity of 762 mA h g −1 and 79.6% capacity retention over 500 cycles) under high-temperature conditions, implying its great potential for practical applications.

Single-atom cobalt encapsulated in carbon nanotubes as an effective catalyst for enhancing sulfur conversion in lithium–sulfur batteries

“…The CoSAC@CNTs present a notable surface area (S BET ) of 920.15 m 2 g −1 , surpassing the reported values of other Co-containing catalysts from previous studies. 58,59 As per computations based on the density functional theory (DFT) methodology, the material has an average pore size of 9.7 nm and an overall pore volume of 1.4 cm 3 g −1 . The process of pyrolysis plays a role in controlling the specific surface area and porosity of substances.…”

Multifunctional Catalytic Hierarchical Interfaces of Ni12P5‐Ni2P Porous Nanosheets Enabled Both Sulfides Reaction Promotion and Li‐Dendrite Suppression for High‐Performance Li–S Full Batteries

“…It indicated that the space double layer could not induce obvious current signals under these testing conditions. [49] Then, using the electrolyte with 0. [50,51] Also, the peak currents of Ni 12 P 5 -Ni 2 P electrodes are higher than those of Ni 12 P 5 and Ni 2 P electrodes, demonstrating the enhanced Li 2 S 6 conversion by the interfaces in Ni 12 P 5 -Ni 2 P.…”

Single-atom site catalysis in Li–S batteries

“…9b). 203 Permeation test results of the functional separator showed CoHP could effectively suppress the shuttle of LiPS through chemical bonding. More importantly, the highly conductive CoHP provided rapid electron transfer to activate efficient single-atom active sites at Co-N 4 , which significantly improved catalytic performance.…”