Aqueous Zn-based Batteries Research Articles

Graphene oxide spontaneous reduction and self-assembly on the zinc metal surface enabling a dendrite-free anode for long-life zinc rechargeable aqueous batteries

Rechargeable aqueous Zn-based batteries are one of the most promising large-scale energy storage devices, benefiting from their eco-friendliness, low cost, high power/energy densities, and safety advantages without using flammable and poisonous organic liquid electrolytes. However, various challenges, such as infinite volume change and growth of dendrites during the electrostripping/electroplating process, lead to low cycling stability (cell shorting) and hinders the application of Zn-based batteries. Herein, a facile and effective approach to reduce graphene oxide (GO) spontaneously by zinc metal is developed and subsequently, the reduced graphene oxide (rGO) is self-assembled to create a layer-by-layer film on the Zn foil surface. This self-assembled, layered rGO on a Zn surface provides a large electroactive area and a soft substrate for Zn electrodeposition, which significantly mitigates Zn dendritic growth by eliminating its driving force. Compared with bare Zn, this composite anode exhibits much lower overpotential (~20 mV at 1 mA cm−2) and excellent long-life cyclability. A full-device with active carbon demonstrates good rate capacity and superior cycling stability. This well-designed anode also provides a useful solution and the possibility of constructing a dendrite-free advanced zinc anode. This is very important to all the zinc-based batteries for grid-scale storage.

Zinc sponge protects rechargeable battery

To exploit zinc’s useful properties in next-generation batteries, researchers have prepared zinc electrodes in a porous spongelike structure. Batteries with such electrodes could be long-lasting, energy dense, and inherently safe, according to a study (Science 2017, DOI: 10.1126/science.aak9991). The relatively low cost of zinc coupled with its wide availability and favorable electrochemical properties should give zinc-based batteries a competitive advantage over other battery chemistries. In particular, Zn batteries could be safer than lithium-ion batteries because Zn ones use aqueous electrolytes instead of the flammable organic kinds standard in Li-ion batteries. But aqueous Zn-based batteries fail quickly. Upon recharging, the metal forms wiry dendrites that can grow uncontrollably and pierce the separator between the electrodes. The dendrites can then connect the positive and negative electrodes and short-circuit the battery. Scientists at the Naval Research Laboratory (NRL) in Washington, D.C., have...