In:
Advanced Energy Materials, Wiley, Vol. 10, No. 7 ( 2020-02)
Abstract:
Rationally designed P2‐K 0.75 [Ni 1/3 Mn 2/3 ]O 2 is introduced as a novel cathode material for potassium‐ion batteries (KIBs). P2‐K 0.75 [Ni 1/3 Mn 2/3 ]O 2 cathode material designed through electrochemical ion‐exchange from P2‐Na 2/3 [Ni 1/3 Mn 2/3 ]O 2 exhibits satisfactory electrode performances; 110 mAh g −1 (20 mA g −1 ) retaining 86% of capacity for 300 cycles and unexpectedly high reversible capacity of about 91 mAh g −1 (1400 mA g −1 ) with excellent capacity retention of 83% over 500 cycles. According to theoretical and experimental investigations, the overall potassium storage mechanism of P2‐K 0.75 [Ni 1/3 Mn 2/3 ]O 2 is revealed to be a single‐phase reaction with small lattice change upon charge and discharge, presenting the Ni 4+/2+ redox couple reaction. Such high power capability is possible through the facile K + migration in the K 0.75 [Ni 1/3 Mn 2/3 ]O 2 structure with a low activation barrier energy of ≈210 meV. These findings indicate that P2‐K 0.75 [Ni 1/3 Mn 2/3 ]O 2 is a promising candidate cathode material for high‐rate and long‐life KIBs.
Type of Medium:
Online Resource
ISSN:
1614-6832
,
1614-6840
DOI:
10.1002/aenm.201903605
Language:
English
Publisher:
Wiley
Publication Date:
2020
detail.hit.zdb_id:
2594556-7