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Impact of Mg 2+ and Al 3+ Substitutions on the Structural and Electrochemical Properties of NASICON‐Na x VMn 0.75 M 0.25 (PO 4 ) 3 (M = Mg and Al) Cathodes for Sodium‐Ion Batteries
Author(s) -
Ghosh Subham,
Barman Nabadyuti,
Senguttuvan Premkumar
Publication year - 2020
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.202003973
Subject(s) - fast ion conductor , electrochemistry , cathode , ion , sodium , jahn–teller effect , materials science , intercalation (chemistry) , sodium ion battery , conductivity , covalent bond , polarization (electrochemistry) , inorganic chemistry , analytical chemistry (journal) , chemistry , electrode , electrolyte , metallurgy , organic chemistry , faraday efficiency , chromatography
Sodium superionic conductor (NASICON)‐Na 4 VMn(PO 4 ) 3 (NVMP) cathode is attractive for sodium‐ion battery application due to its reduced cost and toxicity, and high energy density (≈425 Wh kg −1 ). However, it exhibits significant polarization, limited rate and cycling performances due to its lower electronic conductivity and formation of Jahn–Teller active Mn 3+ during cycling. In this report, a chemical approach is presented to partially replace Mn 2+ of the NVMP framework by Mg 2+ and Al 3+ substitutions. The Mg‐ and Al‐substituted NVMP cathodes present smoother voltage profiles, facile sodium (de)intercalation, enhanced rate performances (80 mA h g −1 at 5C rate) and capacity retention (≈96% after 100 cycles) in comparison with the unsubstituted sample. Their enhanced performances are attributed to suppressed Jahn–Teller effect, increased covalent character and sodium ion vacancies of the NASICON framework. These results highlight the significance of fine tuning the chemical compositions to attain high performance NASICON cathodes.