CORVALLIS, Ore. – Researchers at Oregon State University’s College of Engineering have developed a battery anode based on a new nanostructured alloy that could transform the way energy storage devices are designed and manufactured.
The zinc and manganese-based alloy later opens the door to replacing solutions common in battery electrolytes with something much safer and cheaper, as well as plentiful: seawater.
Results were published today in Nature Communications.
“The world’s energy needs are growing, but the development of next-generation electrochemical energy storage systems with high energy density and long cycle life remains technically challenging,” said Zhenxing Feng, a chemical engineering researcher at OSU. “Chargeable batteries, which use water-based carrier solutions as the electrolytes, are an emerging and safer alternative to lithium-ion batteries. But the energy density of hydraulic systems has been very low, and so is the overflow of water by the lithium, which has hampered the widespread use of aqueous batteries. ”
A battery stores energy in the form of chemical energy and through reactions converts it into the electrical energy needed to power vehicles, cell phones, laptops and many other gadgets and devices. A battery is made up of two ends – the anode and a cathode, usually made of different materials – as well as an separator and an electrolyte, a chemical medium that allows the flow of electricity.
In a lithium-ion battery, as the name suggests, a charge is carried through lithium ions as they move through the electrolyte from the anode to the cathode at the time of discharge, and back again at the time of reconstruction.
“Electrolytes in lithium-ion batteries are typically dissolved in organic solvents, which are flammable and often decompose at high operating voltages,” Feng said. “So there are safety concerns, including with the growth of lithium dendrite at the electrode-electrolyte interface; that can make a short time between the electricity. ”
Dendrites resemble tiny trees growing inside a lithium-ion battery and can break the dehumidifier like thistles growing through cracks in a pavement; the result is unwanted and sometimes unsafe chemical reactions.
Incineration incidents involving lithium-ion batteries in recent years include a fire on a Boeing 787 jet parked in 2013, explosions in Galaxy Note 7 smartphones in 2016 and Tesla Model S fires in 2019.
Aqueous batteries are a promising option for safe and scalable energy storage, Feng said. Aqueous electrolytes are cost competitive, environmentally friendly, capable of fast charge and high power density and very tolerant to abuse.
Large-scale use, however, has been hampered by limited output voltage and low energy density (batteries with higher energy densities can store larger amounts of energy, and batteries with higher power densities can release more energy faster).
But researchers at Oregon State, the University of Central Florida and the University of Houston have designed an anode made of three-dimensional “zinc-M alloy” as the battery anode – where M refers to manganese and metals other.
“Using the alloy with its unique nanostructure not only inhibits dendrite formation by controlling the thermodynamics of the surface reaction and the kinetics of the reaction, but it also shows extremely high stability over thousands of cycles under harsh electrochemical conditions, ”said Feng. “Using zinc can double the cost of lithium, thus improving the energy density of the battery.
“We also tested our water battery using seawater, instead of fully deionized water, as the electrolyte,” he said. “Our work demonstrates commercial potential for large-scale manufacturing of these batteries. ”
Feng and Ph.D. student Maoyu Wang used spectroscopy and X-ray imaging to monitor the atomic and chemical changes of the anode at different operating stages, which determined how the 3D alloy was working in the battery.
“Our theoretical and experimental studies have confirmed that the 3D alloy anode has unprecedented interface stability, achieved by a favorable distribution channel of zinc on the surface of the alloy,” Feng said. “The concept outlined in this collaborative work tends to introduce a paradigm shift in the design of high-performance alloy anodes for both aqueous and non-aqueous batteries, bringing about significant change. on the battery industry. ”
This research was supported by the National Science Foundation.