Non-alloy Mg anode for Ni-MH batteries: Multiple approaches towards a stable cycling performance. (28th May 2021)

• Record Type: Journal Article
• Authors: Xu, Yaolin; Mulder, Fokko M.
• Is Part Of: International journal of hydrogen energy. Volume 46:Number 37(2021)
• Page Start: 19542
• Page End: 19553
• Publication Date: 2021-05-28
• Subjects: Ni-MH batteries -- Electrochemical hydrogen storage -- MgH2 -- Encapsulation -- Ionic liquid -- Alkaline polymer membrane; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2021.03.073
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Mg attracts much research interest as anode material for Ni-MH batteries thanks to its lightweight, cost-effectiveness and high theoretical capacity (2200 mA h g −1 ). However, its practical application is tremendously challenged by the poor hydrogen sorption kinetics, passivation from aggressive aqueous electrolytes, and insulating nature of MgH2 . Mg-based alloys exhibit enhanced hydrogen sorption kinetics and electrical conductivity, but significant amount of costly transition metal elements are required. In this work, we have, for the first time, utilized non-alloyed but catalyzed Mg as anode for Ni-MH batteries. 5 mol.% TiF3 was added to nanosized Mg for accelerating the hydrogen sorption kinetics. Several strategies for preventing the problematic passivation of Mg have been studied, including protective encapsulation of the electrode and utilizing room-temperature/high-temperature ionic liquids and an alkaline polymer membrane as working electrolyte. Promising electrochemical performance has been achieved in this Mg–TiF3 composite anode based Ni-MH batteries with room for further improvements. Graphical abstract: Image 1 Highlights: Non-alloy Mg has been for the first time utilized as anode in Ni-MH batteries. TiF3 catalyzed Mg achieves reversible H sorption to MgH0.13 at room temperature. Nickel foil prevents the passivation of Mg while allows for H permeation. NaOH/KOH eutectic at 200 °C works effectively as electrolyte for Ni-MH batteries. [SET3][TFSI] ionic liquid and PVA-NaOH/KOH membrane are tested as electrolyte.