Renewable energy sources, such as wind and solar power, can help reduce the world’s reliance on fossil fuels. First, energy companies need a safe and efficient way to store energy for later use. Massive lithium-ion batteries can do the job, but they have safety issues and limited lithium availability. Now, researchers report on ACS Dwarf Letters they have made a prototype of an anode-free zinc-based battery that uses low-cost materials, naturally abundant.
Zinc-based aqueous batteries have been previously studied for network-scaled energy storage because of their safety and high energy density. In addition, the materials used to make them are naturally abundant. However, renewable zinc batteries developed so far require thick zinc metal anodes because they contain an excessive amount of zinc that increases the cost. Anodes also tend to form dendrites – crystalline projections of zinc metal that accumulate at the anode during charging – which can have a short-circuit battery. Yunpei Zhu, Yi Cuik and Husam Alshareef asked if a zinc anode was really needed. Based on previous explorations of “anode-free” lithium and sodium metal batteries, the researchers decided to build a battery, the only source of zinc-rich cathode zinc in a copper stream collector.
In the battery, the researchers used a cathode of manganese dioxide, previously interspersed with zinc ions, with electrolytic aqueous solution of zinc trifluoromethanesulfonate and a copper paper stream collector. When charging the zinc metal is covered with copper foil and when discharging the metal is removed, releasing electrons that power the battery. To prevent the formation of dendrites, the researchers covered the copper stream collector with a layer of carbon nanodisc. This layer promoted uniform zinc coating, thus avoiding dendrites and increasing the efficiency of zinc coating and stripping. The battery showed high efficiency, energy density and stability, maintaining 62.8% of the 80 storage capacity after 80 charge and discharge cycles. Researchers say the design of anode-free batteries opens up new directions for the use of zinc-based aqueous batteries in energy storage systems.
Reference: “Anode-free Zn – MnO2 Battery ”by Yunpei Zhu, Yi Cui and Husam N. Alshareef, January 20, 2021, Dwarf Letters.
DOI: 10.1021 / acs.nanolett.0c04519
The authors acknowledge the funding of King Abdullah University of Science and Technology.