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New Barium Vanadate Ba x V 2 O 5 ( x ≈ 0.16) for Fast Lithium Intercalation: Lower Symmetry for Higher Flexibility and Electrochemical Durability
Author(s) -
Zhang Jiliang,
Li Hangkong,
Liao ChangZhong,
Lau Vincent Winghei,
Wong Kam Wa,
Chang ChungKai,
Sheu HwoShuenn,
Shih Kaimin,
Kang YongMook
Publication year - 2020
Publication title -
small methods
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.66
H-Index - 46
ISSN - 2366-9608
DOI - 10.1002/smtd.201900585
Subject(s) - intercalation (chemistry) , isostructural , octahedron , crystallography , barium , vanadate , materials science , cathode , metal , crystal structure , chemistry , inorganic chemistry , metallurgy
Na 0.33 V 2 O 5 ‐type metal vanadates generally show better cycling stability than α‐V 2 O 5 as a cathode in Li‐ion batteries, because they contain enough crystallographic voids that allow for lithium intercalation without significant structural deformation, but metal leaching upon cycling deteriorates their capacity retention. Here a new barium vanadate Ba 0.16(1) V 2 O 5 is reported that does not undergo Ba leaching during cycling and shows a great promise for fast Li intercalation. Sr 0.15(1) V 2 O 5 is isostructural to Na 0.33 V 2 O 5 (space group C 2/ m ), while Ba 0.16(1) V 2 O 5 adopts a new structure (space group P 2 1 / c ), a derivative of Na 0.33 V 2 O 5 . The framework of Ba 0.16(1) V 2 O 5 consists of edge‐shared VO 6 octahedral layers and the VO 5 pyramidal bridge, generating unidirectional tunnels. Unlike the in‐plane arrangement of atoms in Sr 0.15(1) V 2 O 5 , the nonplanar arrangement in Ba 0.16(1) V 2 O 5 makes the host framework more flexible and creates larger voids for Ba. Compared with the combination of displacement and intercalation mechanisms in the Sr 0.15(1) V 2 O 5 cathode, Li intercalation looks dominant in the Ba 0.16(1) V 2 O 5 cathode due to its increased flexibility. Hence, Ba 0.16(1) V 2 O 5 exhibits improved cycling stability compared to Sr 0.15(1) V 2 O 5 , suggesting that lower symmetry leads to higher cyclic stability in the V 2 O 5 ‐related compounds. This study illustrates how guest cations can tune the structural symmetry to modulate the reaction mechanism of electrode materials toward superior performances.