title: Low-Cost High-Energy Potassium Cathode.
abstract: Potassium has as rich an abundance as sodium in the earth, but the development of a K-ion battery is lagging behind because of the higher mass and larger ionic size of K+than that of Li+and Na+, which makes it difficult to identify a high-voltage and high-capacity intercalation cathode host. Here we propose a cyanoperovskite KxMnFe(CN)6(0 ≤ x ≤ 2) as a potassium cathode: high-spin MnIII/MnIIand low-spin FeIII/FeIIcouples have similar energies and exhibit two close plateaus centered at 3.6 V; two active K+per formula unit enable a theoretical specific capacity of 156 mAh g-1; Mn and Fe are the two most-desired transition metals for electrodes because they are cheap and environmental friendly. As a powder prepared by an inexpensive precipitation method, the cathode delivers a specific capacity of 142 mAh g-1. The observed voltage, capacity, and its low cost make it competitive in large-scale electricity storage applications.
authors.affiliation: Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Leigang
authors.identifier: 0000-0002-7359-7915
authors.initials: L
authors.lastname: Xue
authors.affiliation: Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Yutao
authors.initials: Y
authors.lastname: Li
authors.affiliation: Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Hongcai
authors.identifier: 0000-0002-3671-8765
authors.initials: H
authors.lastname: Gao
authors.affiliation: Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Weidong
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Earth and Environmental Sciences Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States.
authors.forename: Xujie
authors.identifier: 0000-0001-8402-7160
authors.initials: X
authors.lastname: Lü
authors.affiliation: Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Watchareeya
authors.initials: W
authors.lastname: Kaveevivitchai
authors.affiliation: Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Arumugam
authors.initials: A
authors.lastname: Manthiram
authors.affiliation: Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: John B
authors.identifier: 0000-0001-9350-3034
authors.initials: JB
authors.lastname: Goodenough