Descripción del proyecto
Materiales catódicos novedosos para baterías de iones de sodio de alta tensión y alta densidad energética
Las baterías de iones de sodio son un candidato prometedor para el posible almacenamiento de electricidad en aplicaciones de red. Sin embargo, su comercialización se ve obstaculizada por la falta de cátodos con alta tensión de salida que proporcionen alta densidad energética. Para hacer frente a esta problemática, el proyecto Mixed Anion Cathodes, financiado con fondos europeos, tiene por objeto diseñar una nueva clase de compuestos con aniones mixtos llamados oxifluoruros de vanadio, que ofrecerán altas capacidades específicas con una tensión operativa superior (≥ 3 V). Los materiales catódicos novedosos se sintetizarán mediante fluorización parcial con reactivos orgánicos no peligrosos y métodos en un solo paso asistidos por microondas. Los cátodos del proyecto se utilizarán para fabricar baterías de iones de sodio de alta densidad energética que ofrezcan un almacenamiento eficiente en la red.
Objetivo
Sodium-ion batteries (SIBs) are being developed and explored as potential electric storage for the grid applications due to infinite resources for sodium at cheaper price. The major impediment for its commercialization is unavailability of cathodes that possesses high output voltage and delivers high energy density. The state-of-art SIB positive electrodes consist of cathodes with the highest output potential (≤ 3.5 V) exhibiting lower specific capacities (150 mAh/g) while V2O5 cathodes delivered high specific capacity (225 mA/g) at low potential (2.5 V). Therefore, it will beneficial to design cathodes with high output voltage and capacity to build high energy density SIBs.
In this project, the above drawbacks are mitigated by designing a new class of mixed anion compounds, vanadium oxyfluorides as novel cathode materials which are expected to deliver high specific capacities at higher operating voltage (≥ 3 V). These compounds are synthesized by partial fluorination using a non-hazardous organic reagents and novel one-pot microwave assisted methods. The as-prepared materials are characterized to identify their chemical compositions and crystallography using TEM, neutron and synchrotron diffraction techniques. These cathodes are subjected to electrochemical testing in a typical CR2032 coin cells. The solid state NMR is used to study the local structure and Na+ mobility inside cathode host while in-situ XPS provides insight into change in electrode composition at various stages of cycling. The electrochemical pulsed technique and impedance spectroscopy are used to determine diffusion coefficient of Na+ and electrochemical mechanism. The optimized materials will be further tested in a pouch cells resembling a real device. Therefore, this project elucidates the designing of a new class of mixed anions cathodes with high output voltage (≥ 3 V) and deliver high specific capacity (225 mAh/g) for fabricating high energy density SIBs (675 Wh/kg) for efficient grid storage.
Ámbito científico
- natural scienceschemical scienceselectrochemistry
- natural scienceschemical sciencesinorganic chemistryalkali metals
- natural sciencesearth and related environmental sciencesgeologymineralogycrystallography
- natural scienceschemical sciencesinorganic chemistrytransition metals
- natural sciencesphysical sciencesopticsspectroscopy
Palabras clave
Programa(s)
Régimen de financiación
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinador
28040 Madrid
España