Role of the voltage window on the capacity retention of P2-Na2/3[Fe1/2Mn1/2]O2 cathode material for rechargeable sodium-ion batteries
[EN] P2-Na-2/3[Fe1/2Mn1/2]O-2 layered oxide is a promising high energy density cathode material for sodium-ion batteries. However, one of its drawbacks is the poor long-term stability in the operating voltage window of 1.5-4.25 V vs Na+/Na that prevents its commercialization. In this work, additiona...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2022 |
| País: | España |
| Institución: | Universidad del País Vasco |
| Repositorio: | Addi. Archivo Digital para la Docencia y la Investigación |
| OAI Identifier: | oai:addi.ehu.eus:10810/55488 |
| Acceso en línea: | http://hdl.handle.net/10810/55488 |
| Access Level: | acceso abierto |
| Palabra clave: | solid-electrolyte interphase electrochemical impedance na2ti3o7 electrodes positive electrode layered oxide ac-impedance stability graphite phase performance |
| Sumario: | [EN] P2-Na-2/3[Fe1/2Mn1/2]O-2 layered oxide is a promising high energy density cathode material for sodium-ion batteries. However, one of its drawbacks is the poor long-term stability in the operating voltage window of 1.5-4.25 V vs Na+/Na that prevents its commercialization. In this work, additional light is shed on the origin of capacity fading, which has been analyzed using a combination of experimental techniques and theoretical methods. Electrochemical impedance spectroscopy has been performed on P2-Na-2/3[Fe1/2Mn1/2]O-2 half-cells operating in two different working voltage windows, one allowing and one preventing the high voltage phase transition occurring in P2-Na-2/3[Fe1/2Mn1/2]O-2 above 4.0 V vs Na+/Na; so as to unveil the transport properties at different states of charge and correlate them with the existing phases in P2-Na-2/3[Fe1/2Mn1/2]O-2. Supporting X-ray photoelectron spectroscopy experiments to elucidate the surface properties along with theoretical calculations have concluded that the formed electrode-electrolyte interphase is very thin and stable, mainly composed by inorganic species, and reveal that the structural phase transition at high voltage from P2- to "Z"/OP4-oxygen stacking is associated with a drastic increased in the bulk electronic resistance of P2-Na-2/3[Fe1/2Mn1/2]O-2 electrodes which is one of the causes of the observed capacity fading. P2-Na-2/3[Fe1/2Mn1/2]O-2 is a promising high energy density cathode material for rechargeable sodium-ion batteries, but its poor long-term stability in the operating voltage window of 1.5-4.25 V vs Na+/Na hinders its commercial application. Here, the authors use a combination of electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and DFT calculations to investigate the origin of the capacity fading, which is attributed to an increase in bulk electronic resistance at high voltage that, among other factors, is nested in a structural phase transition. |
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