阴极
材料科学
离子
组态熵
氧化物
钠
相变
热力学
化学
冶金
物理化学
物理
有机化学
作者
Sören L. Dreyer,Ruizhuo Zhang,Junbo Wang,Aleksandr Kondrakov,Qingsong Wang,Torsten Brezesinski,Jürgen Janek
出处
期刊:JPhys energy
[IOP Publishing]
日期:2023-05-19
卷期号:5 (3): 035002-035002
被引量:4
标识
DOI:10.1088/2515-7655/acd41a
摘要
Abstract Sodium-ion batteries (SIBs) see intensive research and commercialization efforts, aiming to establish them as an alternative to lithium-ion batteries. Among the reported cathode material families for SIBs, Na-deficient P2-type layered oxides are promising candidates, benefiting from fast sodium diffusion and therefore high charge/discharge rates. However, upon sodium extraction at high potentials, a transition from the P2 to O2 phase occurs, with the corresponding change in cell volume resulting in particle fracture and capacity degradation. A possible solution to this is to increase configurational entropy by introducing more elements into the transition-metal layer (so-called high-entropy concept), leading to some kind of structural stabilization. In this work, the acoustic emission (AE) of a series of P2-type layered oxide cathodes with increasing configurational entropy [Na 0.67 (Mn 0.55 Ni 0.21 Co 0.24 )O 2 , Na 0.67 (Mn 0.45 Ni 0.18 Co 0.24 Ti 0.1 Mg 0.03 )O 2 and Na 0.67 (Mn 0.45 Ni 0.18 Co 0.18 Ti 0.1 Mg 0.03 Al 0.04 Fe 0.02 )O 2 ] is recorded during SIB operation and correlated to the materials properties, namely change in c lattice parameter and cracking behavior. A structure-property relationship between entropy, manifested in the extent of phase transition, and detected AE is derived, supported by the classification of signals by peak frequency. This classification in combination with microscopy imaging allows to distinguish between inter- and intragranular fracture. Relatively more intergranular and less intragranular crack formation is observed with increasing configurational entropy.
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