Lithium-ion batteries are critical for modern life, powering laptops, cellphones, and other devices; however, there is a safety risk — the batteries can catch fire. Zinc-based aqueous batteries avoid the fire hazard by using a water-based electrolyte instead of the conventional chemical solvent. But uncontrolled dendrite growth limits their ability to provide the high performance and long life needed for practical applications.
Researchers have created a new 3D zinc-manganese nano-alloy anode that results in a stable, high-performance, dendrite-free aqueous battery using seawater as the electrolyte. The discovery offers promise for energy storage and other applications including electric vehicles.
The team also developed an in situ optical visualization technique, allowing them to directly observe the reaction dynamics on the anode in real time. The platform provides direct evidence and visualization of the reaction kinetics. Testing determined that the novel 3D zinc-manganese nano-alloy anode remained stable without degrading throughout 1,000 hours of charge/discharge cycling under high current density.
The anode is the electrode that releases current from a battery, while electrolytes are the medium through which the ionic charge flows between the cathode and anode. Using seawater as the electrolyte rather than highly purified water offers another avenue for lowering battery cost.
Traditional anode materials used in aqueous batteries have been prone to dendrites — tiny growths that can cause the battery to lose power. The new strategy efficiently minimizes and suppresses dendrite formation in aqueous systems by controlling surface reaction thermodynamics with a zinc alloy and reaction kinetics by a three-dimensional structure.