Cobalt Oxide/Graphene Nanosheets/Hexagonal Boron Nitride (Co₃O₄/CoO/GNS/h-BN) Catalyst for High Sulfur Utilization in Li–S Batteries at Elevated Temperatures

Abstract

The high theoretical energy density and low cost of lithium–sulfur (Li–S) batteries make them promising candidates for future energy storage devices. Here, we developed Co3O4/CoO/graphene nanosheets (GNS)/hexagonal boron nitride (h-BN) nanocomposite-based sulfur as cathodes for Li–S batteries. Due to the synergistic effects of GNS/h-BN and Co3O4/CoO, the reported Co3O4/CoO/GNS/h-BN nanocomposites not only effectively trap lithium polysulfides but also can accelerate the redox kinetics for the conversion of polysulfides. The enhanced electrochemical activity of Co3O4/CoO/GNS/h-BN is due to the (111) exposed surface of Co3O4 and the formation of CoO on Co3O4, which is the catalytically active phase of Co3O4-based catalysts. GNS/h-BN provides a large surface area for the high exposure of the Co3O4/CoO catalyst and can also influence the catalytic activity due to enhanced charge transfer. Co3O4/CoO/GNS/h-BN/S nanocomposites showed superior electrochemical performances and high sulfur utilization compared to GNS/h-BN/S and Co3O4/CoO/S. More significantly, a very high capacity retention of 89% was obtained with a reversible capacity of 356.29 mA h/g after 250 cycles at a current rate of 1 C. Also, enhanced redox conversion of lithium polysulfides was observed when the cell was operated at higher temperatures. Besides cobalt oxide, other metal oxides such as Fe2O3 and SnO2 on GNS/h-BN could also be potential candidates for high-performance Li–S batteries.

Recent Breakthroughs in the Bottleneck of Cathode Materials for Li–S Batteries

“…In addition, the metallic cobalt load further catalyzed the conversion of LiPSs. The highly active site Co 2+ /Co 3+ formed by the combination of Co 3 O 4 and CoO could perform strong chemisorption on LiPSs in the synthesized Co 3 O 4 /CoO/GNS/ h -BN/S . Graphene and h -BN also had coupling effects on the loading of Co 3 O 4 and CoO.…”

Metal-Free Catalytic Oxidative Desulfurization of Fuels─A Review

“…These are highly porous 2D materials containing sp 2 -hybridized B–N bonds, with a six-membered ring arrangement of boron and nitrogen atoms. They possess high surface area, high resistance to oxidation, and chemical inertness and have numerous structural defects . Hexagonal BN materials can activate oxidants, like H 2 O 2 , thereby generating OH radicals suitable for ODS reactions.…”

“…They possess high surface area, high resistance to oxidation, and chemical inertness and have numerous structural defects. 182 Hexagonal BN materials can activate oxidants, like H 2 O 2 , thereby generating OH radicals suitable for ODS reactions. Wu et al 183 developed a few-layer-structured h-BN catalyst for ODS of DBT and 4,6-DMDBT with H 2 O 2 as an oxidant.…”

Overview of the Latest Developments and Perspectives about Noncarbon Sulfur Host Materials for High Performance Lithium–Sulfur Batteries

“…Of course, a lithium anode also has many problems that need to be solved. Because lithium metal has a high reactivity, it will react with the electrolyte to form a solid electrolyte interface film (SEI) on the surface, and the inhomogeneity of the SEI cannot sufficiently passivate lithium. , On the metal surface, lithium metal and the electrolyte will have an undesirable reaction, which will eventually lead to the degradation of the specific capacity and life of the battery . The main problem is that the growth of lithium dendrites will penetrate the separator and cause a short circuit inside the battery, causing safety issues such as fire or explosion .…”

“…5,33 On the metal surface, lithium metal and the electrolyte will have an undesirable reaction, which will eventually lead to the degradation of the specific capacity and life of the battery. 45 The main problem is that the growth of lithium dendrites will penetrate the separator and cause a short circuit inside the battery, causing safety issues such as fire or explosion. 46 Due to the low conductivity of sulfur, it cannot be directly used as a cathode material.…”