DOCTORAL CANDIDATE
Anshika Binjrajka

SUPERVISORS
Junxian Zhang, Institut de Chimie et des Matériaux Paris-Est (ICMPE)
Mickael Mateos, Institut de Chimie et des Matériaux Paris-Est (ICMPE)
Prof. Francois Aguey-Zinsou, The University of Sydney (USYD)

Chemistry, Materials science, Solid-state chemistry, Electrochemistry

Hydrides have outstanding properties as both negative electrodes and solid electrolytes for Li-ion batteries. Metal hydrides can operate as anodes through the conversion reaction MHx + xLi <-> M + xLiH leading to high gravimetric (1000-2000 mAh/g) and volumetric (2000-4000 mAh/cm3) capacities with a typical potential < 0.6 V.

As solid electrolytes, complex hydrides have superior mechanical deformability and promising Li-ion conductivity of the order of 0.1 mS/cm at room temperature. The association of hydrides both as anode and solid electrolyte materials is also expected to ensure chemical compatibility of all the battery components and thus superior performances. However, the reversibility of the electrochemical conversion reaction of metal hydrides with lithium is poor and the level of Li-ion conductivity in complex hydrides at room temperature is still too low.

This PhD project will be devoted to study the association of novel metal hydrides as anode materials and complex hydrides as solid electrolytes for advancing all hydride-based Li-ion batteries working at room temperature. For overcoming current hurdles, novel hydride nanocomposites will be prepared with phase composition allowing for fast Li-mobility at room temperature. The goal will be to encompass fast Li-mobility in the active material of the electrode with high Li-conductivity in the solid electrolyte to gain a synergetic effect between the two components. The conductivity of the solid electrolyte will be improved in line with current nanocomposite strategies. Electrochemical studies to evaluate the performances of solid half-cells will be first done at high temperatures to minimize kinetic limitations and then this work will be progressed toward room temperature operation. If results are successful, the concept will be extended to Na-ion cells.