Lithium metal anode batteries are considered the future of battery design because they have 10 times the capacity of commercially available graphite anode batteries, which could significantly increase the driving range of electric vehicles. This new research is an important step towards more practical solid-state batteries for industrial and commercial applications.
One of the biggest challenges in battery design is the formation of dendrites on the anode surface. These dendritic structures extend into the electrolyte like tree roots, piercing the barrier separating the anode and cathode, leading to short circuits or even fires.
In 2021, the team developed a method for dealing with dendrites. They designed a multilayer battery that sandwiched materials with different stabilities between the anode and cathode. However, this design could not completely prevent lithium dendrite infiltration; it only mitigated it as much as possible through control and coating.
The team has successfully contained the lithiation reaction and promoted uniform plating of the lithium metal layer by using micron-sized silicon particles in the anode, thereby preventing dendrite formation. In this design, the lithiation reaction is confined to a shallow surface as lithium ions move from the cathode to the anode during charging. The ions adhere to the surface of the silicon particles but do not penetrate further.
In solid-state batteries, ions on the silicon surface are confined and undergo a dynamic process of lithiation, forming a lithium metal plating layer around the silicon core. In the new design, these coating particles form a uniform surface, preventing dendrite growth. Moreover, because plating and stripping can occur rapidly on a flat surface, the battery can be fully charged in approximately less than 10 minutes.
Researchers have created a postage stamp-sized version of the pouch battery, which is 10 to 20 times larger than most button batteries made in university labs. This battery retains 80% of its capacity after 6,000 charge-discharge cycles, outperforming other pouch batteries on the market today.
Many of us have experienced this: after using a phone or computer for a period of time, the battery capacity decreases, and the time it takes to deplete the battery becomes shorter. A major reason for the capacity decline of lithium batteries is the irreversible loss of lithium. Dendrites on the anode surface are also an irreversible lithium compound, and their growth mechanism is complex. This time, researchers used a new design to limit the lithiation reaction, preventing dendrite growth and shortening the battery charging time. This new type of battery can power more electric products; for example, developing high-capacity, safe, and fast-charging batteries could further drive the development of the electric vehicle industry.
