Anode-Free Zinc-Based Battery Is the Future of Renewable Energy Storage

With a new base material that is naturally abundant and lower costing, an anode-free zinc-based battery could be the safer, more cost-effective alternative for renewable energy storage.

Renewable energy sources - such as solar, hydro, and wind power - could help reduce the world's fossil fuel dependence. It does, however, require storage for transport and later use. While lithium-ion batteries take the lead in conventional energy storage, it remains restricted by safety issues and lithium scarcity. Researchers reported developing a prototype for a zinc-based battery in the journal ACS Nano Letters, January 20.

Newest Innovations In Consumer Technology On Display At 2015 International CES

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LAS VEGAS, NV - JANUARY 06: Lithium-ion batteries are displayed at the Panasonic booth during the 2015 International CES at the Las Vegas Convention Center on January 6, 2015, in Las Vegas, Nevada. CES, the world's largest annual consumer technology trade show, runs through January 9 and is expected to feature 3,600 exhibitors showing off their latest products and services to about 150,000 attendees.

Anode-Free, Zinc-Based Battery

There have been studies exploring the potential applications for aqueous zinc-based rechargeable batteries, from small setups to grid-scale energy storage, mainly because of the high energy density potential and safety advantages. However, these batteries required thick zinc metal anodes, which in turn requires more zinc and adds to the cost. Also, anodes are prone to the formation of dendrites, crystalline projections of zinc metal that accumulate on the anode part during charging and could later short-circuit the battery.

The team of Yunpei Zhu, Yi Cui, and Husam Alshareef were curious whether zinc anodes were as necessary as previously thought. Inspired by previous works on anode-free sodium-metal and lithium batteries, they developed a battery that relied on a zinc-rich cathode to provide zinc plating to a copper current collector.

To achieve this, researchers used a nanocarbon nucleation layer. Using manganese dioxide for the cathode material, it was pre-intercalated with zinc ions, aqueous zinc trifluoromethanesulfonate electrolyte solution, and a copper foil current collector. While charging, the zinc metal starts to get plated onto the copper foil, and during discharge, zinc is stripped off the copper layer. They conducted electrochemical studies on the new setup, observing that their design allowed uniform zinc electrodeposition that maintains high efficiency and stability over a range of current densities and plating capacities.

Their anode-free configuration showed that the zinc-based battery achieved a 68.2 percent capacity retention after 80 charging-discharging cycles.

Limits of Lithium Batteries

Lithium-ion batteries are capable of having high voltage and charge storage capacity per unit mass and unit volume, boasting one of the highest energy densities among rechargeable battery technologies. It is because Lithium is the lightest metal under standard conditions and is ideal for making portable and powerful batteries.

However, lithium-ion batteries still have their disadvantages, particularly in terms of safety. These batteries are known for their tendency to overheat and get damaged at high voltage applications. For more industrial applications, its fragility requires that it has its own protection circuit to keep it from being damaged.

Another limitation that limits the widespread adoption of lithium-ion batteries in larger-scale applications is its cost - which averages 40 percent higher than Nickel and Cadmium (Ni-Cd) batteries.