Catalytically Active Site Identification of Molybdenum Disulfide as Gas Cathode in a Nonaqueous Li-CO2Battery
Journal
ACS Applied Materials and Interfaces
Journal Volume
13
Journal Issue
5
Pages
6156-6167
Date Issued
2021
Author(s)
Abstract
Li-CO2 batteries have recently attracted attention as promising candidates for next-generation energy storage devices due to their extremely high theoretical energy density. The real application of Li-CO2 cells involves addressing several drawbacks, including high charging potential, poor coulombic efficiency, and low rechargeability. Molybdenum disulfide supported on carbon nanotubes (MoS2/CNT) with various ratios functioned as a cathode catalyst for Li-CO2 batteries. The optimal MoS2/CNT composite achieved a maximum discharge capacity of 8551 mAh g-1 with a coulombic efficiency of 96.7%. This hybrid also obtained an initial charging plateau of 3.87 V at a current density of 100 mA g-1 with a cutoff capacity of 500 mAh g-1. It provided ideal electrochemical stability of 142 cycles at the current densities of 100 mA g-1, which was comparable with that of some precious metal catalysts. This optimized MoS2/CNT was also cycled at 200 and 400 mA g-1 for 112 and 55 times, respectively. Density functional theory calculations demonstrated that the sulfided Mo-edge (s-Mo-edge) on MoS2 materials showed appropriate adsorption strengths of Li, CO2, and Li2CO3. Moreover, joint results of Raman profiles and extended X-ray absorption fine structure spectra elucidated that the catalytic efficiencies of MoS2/CNT hybrids were proportional to the quantities of exposed s-Mo-edge active sites. ? 2021 American Chemical Society.
Subjects
Carbon dioxide; Catalysts; Cathodes; Charging (batteries); Density functional theory; Energy storage; Extended X ray absorption fine structure spectroscopy; Layered semiconductors; Lithium compounds; Secondary batteries; Sulfur compounds; X ray absorption; Adsorption strength; Catalytic efficiencies; Coulombic efficiency; Discharge capacities; Electrochemical stabilities; Extended x-ray absorption fine structure spectrum; Molybdenum disulfide; Precious metal catalysts; Molybdenum compounds
SDGs
Type
journal article