ABSTRACT
The Daniell cell (Cu vs. Zn), was invented almost two centuries ago, but has been set aside due to its non-rechargeable nature and limited energy density. However, these cells are exceptionally sustainable because they do not require rare earth elements, are aqueous and easy to recycle. This work addresses key challenges in making Daniell cells relevant to our current energy crisis. First, we propose new approaches to stabilise Zn and Cu plating and stripping processes and create a rechargeable cell. Second, we replace salt bridges with an anion exchange membrane, or a bipolar membrane for alkaline-acid hybrid Zn-Cu batteries operating at 1.56 V. Finally, we apply these changes in pouch cells in order to increase energy and power density. These combined developments result in a rechargeable Daniell cell, which can achieve high areal capacities of 5 mA h cm-2 and can easily be implemented in 1 A h pouch cells.
ABSTRACT
Aqueous Fe-ion batteries (FIBs) have gradually emerged in recent years due to their inherent merits. Herein, we constructed a Mg-substituted Prussian blue analogue (MgFeHCF) as cathode for FIBs, achieving higher capacity (96 mA h g-1) and better stability (70.9% capacity retention over 500 cycles). The Fe-ion storage mechanism was revealed using the in situ XRD technique and DFT calculations were employed to analyse the battery performance.
