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δ‐MnO 2 Nanofibers: A Promising Cathode Material for New Aluminum‐Ion Batteries
Author(s) -
Almodóvar Paloma,
Giraldo David A.,
Chancón Joaquín,
ÁlvarezSerrano Inmaculada,
López María Luisa
Publication year - 2020
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.202000425
Subject(s) - faraday efficiency , materials science , electrochemistry , cathode , raman spectroscopy , intercalation (chemistry) , nanofiber , battery (electricity) , ion , formula unit , chemical engineering , aluminium , analytical chemistry (journal) , nanotechnology , electrode , inorganic chemistry , composite material , chemistry , crystal structure , crystallography , thermodynamics , organic chemistry , power (physics) , physics , engineering , optics
δ‐MnO 2 nanofibers, synthesized by using a simple, low‐cost sol‐gel method, showed high electrochemical performance as a cathode for rechargeable Al‐ion batteries (AIBs). δ‐MnO 2 presented an initial discharge capacity of 59 mA h g −1 and stabilized at 37 mA h g −1 at a current rate of 100 mA g −1 after 15 cycles and for more than 100 cycles with almost a 99 % coulombic efficiency. Different plateaus in charge/discharge curves, consistent with CV peaks, revealed the Al‐ion insertion/deinsertion and the electrochemical stability of the battery. Moreover, different rate CV measurements revealed the pseudocapacitive behavior of δ‐MnO 2 in AIBs. The obtained charge/discharge capacities are ten times higher than previous studies performed with this material. Ex situ Raman and high‐resolution TEM measurements in different charge/discharge states revealed structural information of δ‐MnO 2 upon Al‐ion intercalation/deintercalation.