In a study published in the journal Nano Letters, scientists Yunpei Zhu, Yi Cui, and Husam Alshareef say they drew inspiration from previous explorations of “anode-free” lithium and sodium-metal batteries and decided to make a battery in which a zinc-rich cathode is the sole source for zinc plating onto a copper current collector.

Their main goal was to address a big problem linked to previously explored aqueous zinc-based batteries. The issue was that, even though they provided safety and high energy density when compared to other batteries, they required thick zinc anodes, which contain large amounts the metal and, thus, were more costly.

In their prototype, however, the team of researchers used a manganese dioxide cathode that they pre-intercalated with zinc ions, an aqueous zinc trifluoromethanesulfonate electrolyte solution, and a copper foil current collector. During charging, zinc metal gets plated onto the copper foil, and during discharging the metal is stripped off, releasing electrons that power the battery.

To prevent dendrites from forming, the experts coated the copper current collector with a layer of carbon nanodiscs. This layer promoted uniform zinc plating, thereby preventing dendrites and it also increased the efficiency of zinc plating and stripping.

In their paper, Zhu Cui and Alshareef report that the battery showed high efficiency, energy density, and stability, retaining 62.8% of its storage capacity after 80 charging and discharging cycles. Thus, they believe that their anode-free battery design provides new directions for using aqueous zinc-based batteries in energy storage systems.