title: Role of Nitrogen-Doped Graphene for Improved High-Capacity Potassium Ion Battery Anodes.
abstract: Potassium is an earth abundant alternative to lithium for rechargeable batteries, but a critical limitation in potassium ion battery anodes is the low capacity of KC8graphite intercalation compounds in comparison to conventional LiC6. Here we demonstrate that nitrogen doping of few-layered graphene can increase the storage capacity of potassium from a theoretical maximum of 278 mAh/g in graphite to over 350 mAh/g, competitive with anode capacity in commercial lithium ion batteries and the highest reported anode capacity so far for potassium ion batteries. Control studies distinguish the importance of nitrogen dopant sites as opposed to sp3carbon defect sites to achieve the improved performance, which also enables >6× increase in rate performance of doped vs undoped materials. Finally, in situ Raman spectroscopy studies elucidate the staging sequence for doped and undoped materials and demonstrate the mechanism of the observed capacity enhancement to be correlated with distributed storage at local nitrogen sites in a staged KC8compound. This study demonstrates a pathway to overcome the limitations of graphitic carbons for anodes in potassium ion batteries by atomically precise engineering of nanomaterials.
authors.affiliation: Interdisciplinary Materials Science Program, ‡Department of Mechanical Engineering, and §Department of Chemical and Biomolecular Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Keith
authors.initials: K
authors.lastname: Share
authors.affiliation: Interdisciplinary Materials Science Program, ‡Department of Mechanical Engineering, and §Department of Chemical and Biomolecular Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Adam P
authors.initials: AP
authors.lastname: Cohn
authors.affiliation: Interdisciplinary Materials Science Program, ‡Department of Mechanical Engineering, and §Department of Chemical and Biomolecular Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Rachel
authors.initials: R
authors.lastname: Carter
authors.affiliation: Interdisciplinary Materials Science Program, ‡Department of Mechanical Engineering, and §Department of Chemical and Biomolecular Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Bridget
authors.initials: B
authors.lastname: Rogers
authors.affiliation: Interdisciplinary Materials Science Program, ‡Department of Mechanical Engineering, and §Department of Chemical and Biomolecular Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
authors.forename: Cary L
authors.initials: CL
authors.lastname: Pint
keywords: anode; graphite intercalation compounds; in situ Raman spectroscopy; nitrogen doping; potassium ion battery