TY - JOUR
T1 - Importance of Crystallographic Sites on Sodium-Ion Extraction from NASICON-Structured Cathodes for Sodium-Ion Batteries
AU - Wang, Qianchen
AU - Gao, Hongcai
AU - Li, Jingbo
AU - Liu, Gui Bin
AU - Jin, Haibo
N1 - Publisher Copyright:
©
PY - 2021/3/31
Y1 - 2021/3/31
N2 - The V4+/V3+ (3.4 V) redox couple has been well-documented in cathode material Na3V2(PO4)3 for sodium-ion batteries. Recently, partial cation substitution at the vanadium site of Na3V2(PO4)3 has been actively explored to access the V5+/V4+ redox couple to achieve high energy density. However, the V5+/V4+ redox couple in partially substituted Na3V2(PO4)3 has a voltage far below its theoretical voltage in Na3V2(PO4)3, and the access of the V5+/V4+ redox reaction is very limited. In this work, we compare the extraction/insertion behavior of sodium ions from/into two isostructural compounds of Na3VGa(PO4)3 and Na3VAl(PO4)3, found that, by DFT calculations, the lower potential of the V5+/V4+ redox couple in Na3VM(PO4)3 (M = Ga or Al) than that in Na3V2(PO4)3 is because of the extraction/insertion of sodium ions through the V5+/V4+ redox reaction at different crystallographic sites, that is, sodium ions extracting from the Na(2) site in Na3VM(PO4)3 while from the Na(1) site in Na3V2(PO4)3, and further evidenced that the full access of the V5+/V4+ redox reaction is restrained by the excessive diffusion activation energy in Na3VM(PO4)3.
AB - The V4+/V3+ (3.4 V) redox couple has been well-documented in cathode material Na3V2(PO4)3 for sodium-ion batteries. Recently, partial cation substitution at the vanadium site of Na3V2(PO4)3 has been actively explored to access the V5+/V4+ redox couple to achieve high energy density. However, the V5+/V4+ redox couple in partially substituted Na3V2(PO4)3 has a voltage far below its theoretical voltage in Na3V2(PO4)3, and the access of the V5+/V4+ redox reaction is very limited. In this work, we compare the extraction/insertion behavior of sodium ions from/into two isostructural compounds of Na3VGa(PO4)3 and Na3VAl(PO4)3, found that, by DFT calculations, the lower potential of the V5+/V4+ redox couple in Na3VM(PO4)3 (M = Ga or Al) than that in Na3V2(PO4)3 is because of the extraction/insertion of sodium ions through the V5+/V4+ redox reaction at different crystallographic sites, that is, sodium ions extracting from the Na(2) site in Na3VM(PO4)3 while from the Na(1) site in Na3V2(PO4)3, and further evidenced that the full access of the V5+/V4+ redox reaction is restrained by the excessive diffusion activation energy in Na3VM(PO4)3.
KW - NASICON-structured cathodes
KW - high-voltage cathodes
KW - sodium-ion batteries
KW - sodium-ion diffusion barriers
KW - the V/Vredox couple
UR - http://www.scopus.com/inward/record.url?scp=85103682223&partnerID=8YFLogxK
U2 - 10.1021/acsami.1c01663
DO - 10.1021/acsami.1c01663
M3 - Article
C2 - 33749228
AN - SCOPUS:85103682223
SN - 1944-8244
VL - 13
SP - 14312
EP - 14320
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 12
ER -
