Thick film formation on Li-O2 cathodes – breaking the true capacity barrier

Abstract The theoretical energy density of Li-O2 batteries is more than an order of magnitude larger than the current generation of Li-ion batteries. However, their practical performance is far less, in part due to their low true capacities, that is, capacity including the mass of the typically poro...

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Main Authors: Michael D. Womble, Kevin R. McKenzie, Michael J. Wagner
Format: Article
Language:English
Published: Nature Portfolio 2025-02-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-025-89655-0
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author Michael D. Womble
Kevin R. McKenzie
Michael J. Wagner
author_facet Michael D. Womble
Kevin R. McKenzie
Michael J. Wagner
author_sort Michael D. Womble
collection DOAJ
description Abstract The theoretical energy density of Li-O2 batteries is more than an order of magnitude larger than the current generation of Li-ion batteries. However, their practical performance is far less, in part due to their low true capacities, that is, capacity including the mass of the typically porous active material, electrolyte in the pores and the Li2O2 discharge product. This is further limited by the particulate nature of the product, yielding a theoretical maximum packing density of 74%, impacting both gravimetric and volumetric capacities. Here we introduce carbon nanochains (CNCs), a material synthesized from biomass that is structurally similar to a commonly studied cathode material, multiwalled carbon nanotubes (MWCNTs). CNCs form densely packed agglomerates with mesoporosity that is similar to that of MWCNTs but far less microporosity, resulting in nearly twice the volumetric capacity and significantly larger true capacity despite obtaining essentially identical gravimetric capacity. Finally, while the initial discharge product is found to be toroidal Li2O2 particles typical of Li-O2 cathodes, it proceeds with the formation of thick films covering the surface of the cathode. This is, to our knowledge, the first report of thick film formation in Li-O2 cells, overcoming the 74% density limit of particulate formation.
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spelling doaj-art-2267618ddcf0459292871e40f524cbf22025-08-20T03:11:07ZengNature PortfolioScientific Reports2045-23222025-02-0115111110.1038/s41598-025-89655-0Thick film formation on Li-O2 cathodes – breaking the true capacity barrierMichael D. Womble0Kevin R. McKenzie1Michael J. Wagner2Department of Chemistry, The George Washington UniversityDepartment of Chemistry, The George Washington UniversityDepartment of Chemistry, The George Washington UniversityAbstract The theoretical energy density of Li-O2 batteries is more than an order of magnitude larger than the current generation of Li-ion batteries. However, their practical performance is far less, in part due to their low true capacities, that is, capacity including the mass of the typically porous active material, electrolyte in the pores and the Li2O2 discharge product. This is further limited by the particulate nature of the product, yielding a theoretical maximum packing density of 74%, impacting both gravimetric and volumetric capacities. Here we introduce carbon nanochains (CNCs), a material synthesized from biomass that is structurally similar to a commonly studied cathode material, multiwalled carbon nanotubes (MWCNTs). CNCs form densely packed agglomerates with mesoporosity that is similar to that of MWCNTs but far less microporosity, resulting in nearly twice the volumetric capacity and significantly larger true capacity despite obtaining essentially identical gravimetric capacity. Finally, while the initial discharge product is found to be toroidal Li2O2 particles typical of Li-O2 cathodes, it proceeds with the formation of thick films covering the surface of the cathode. This is, to our knowledge, the first report of thick film formation in Li-O2 cells, overcoming the 74% density limit of particulate formation.https://doi.org/10.1038/s41598-025-89655-0
spellingShingle Michael D. Womble
Kevin R. McKenzie
Michael J. Wagner
Thick film formation on Li-O2 cathodes – breaking the true capacity barrier
Scientific Reports
title Thick film formation on Li-O2 cathodes – breaking the true capacity barrier
title_full Thick film formation on Li-O2 cathodes – breaking the true capacity barrier
title_fullStr Thick film formation on Li-O2 cathodes – breaking the true capacity barrier
title_full_unstemmed Thick film formation on Li-O2 cathodes – breaking the true capacity barrier
title_short Thick film formation on Li-O2 cathodes – breaking the true capacity barrier
title_sort thick film formation on li o2 cathodes breaking the true capacity barrier
url https://doi.org/10.1038/s41598-025-89655-0
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