University of North Texas

Wonbong Choi

Eunho Cha

Two-dimensional (2D) material-based metal or alloy catalysts synthesized on carbon materials (e.g., carbon nanotubes) prevent polysulfide shuttling and overcome technical challenges for developing practical lithium-sulfur (Li—S) batteries. Soluble lithium polysulfides (LiPSs) tend to shuttle during battery cycling and corrode a Li anode, leading to eventual performance fading in the Li—S battery. This shuttle effect can be reduced by accelerating the conversion of the dissolved polysulfides to the insoluble LiPSs and back to the sulfur. A 2D material-based alloy or 2D material synthesized on carbon materials can suppress polysulfide shuttling by catalyzing polysulfide reactions. 2D material-based alloys with 2H (semiconducting)-1T (metallic) mixed phase exhibit synergistic effects of accelerated electron transfer and catalytic performance as confirmed by the lower charge-transfer resistance of carbon nanotube (CNT)-S cathode and the high binding energy of LiPSs to the catalyst.

Two dimensional (2D) transition metal dichalcogenide (TMD) materials and alloys as catalysts for cathode in lithium-sulfur (Li-S) batteries

Two-dimensional (2D) material-based metal or alloy catalysts synthesized on carbon materials (e.g., carbon nanotubes) prevent polysulfide shuttling and overcome technical challenges for developing practical lithium-sulfur (Li&#x2014;S) batteries. Soluble lithium polysulfides (LiPSs) tend to shuttle during battery cycling and corrode a Li anode, leading to eventual performance fading in the Li&#x2014;S battery. This shuttle effect can be reduced by accelerating the conversion of the dissolved polysulfides to the insoluble LiPSs and back to the sulfur. A 2D material-based alloy or 2D material synthesized on carbon materials can suppress polysulfide shuttling by catalyzing polysulfide reactions. 2D material-based alloys with 2H (semiconducting)&#x2014;1T (metallic) mixed phase exhibit synergistic effects of accelerated electron transfer and catalytic performance as confirmed by the lower charge-transfer resistance of carbon nanotube (CNT)&#x2014;S cathode and the high binding energy of LiPSs to the catalyst.

Two dimensional (2D) transition metal dichalcogenide (TMD) materials and alloys as catalysts for cathode in lithium sulfur (Li-S) batteries

The present application relates to methods for depositing two-dimensional materials (e.g., MoS, WS, MoTe, MoSe, WSe, BN, BN&#x2014;C composite, and the like) onto lithium electrodes. Battery systems incorporating lithium metal electrodes coated with two-dimensional materials are also described. Methods may include intercalating the two-dimensional materials to facilitate flow of Lithium ions in and out of the lithium electrode. Two-dimensional material coated lithium electrodes provide for high cycling stability and significant performance improvements. Systems and methods further provide electrodes having carbon structures (e.g., carbon nanotubes (CNTs), graphene, porous carbon, free-standing 3D CNTs, etc.) with sulfur coatings.

Passivation of lithium metal by two-dimensional materials for rechargeable batteries

The invention includes supercapacitors and methods of making supercapacitor by fabricating transition metal dichalcogenide (MX) layers using a combination of magnetron sputtering followed by chemical vapor deposition.

Growing community of inventors

Coppell, TX, United States of America

Wonbong Choi