New solid-state battery takes just minutes to fully charge, helping develop better lithium metal batteries

Researchers at Harvard University's School of Engineering and Applied Sciences have developed a new type of lithium metal battery. The battery can be charged and discharged at least 6,000 times, more than any other pouch battery, and can be fully charged in minutes. The research not only describes a new way to create solid-state batteries using lithium metal anodes, but also provides new insights into potentially revolutionary battery materials. The research was published in the new issue of "Nature Materials".

Lithium metal anode batteries are considered the way forward in battery design because they have 10 times the capacity of commercial graphite anode batteries and can significantly increase the range of electric vehicles. The new research is an important step toward 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, puncturing the barrier that separates the anode and cathode, causing the battery to short circuit or even catch fire.

In 2021, the team developed a method for dealing with dendrites. They designed a multilayer battery that sandwiched materials of varying stability between the anode and cathode. However, this design cannot completely prevent the penetration of lithium dendrites. It can only try to prevent this penetration through control and coating.

This time, the team used micron-sized silicon particles in the anode to limit the lithiation reaction and promote uniform plating of the lithium metal layer, thus preventing the formation of dendrites. In this design, the lithiation reaction is confined to the 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 around the silicon core. In the new design, these coating particles create a uniform surface that prevents dendrite growth. And because plating and stripping can occur quickly on a flat surface, the battery can be fully charged in approximately less than 10 minutes.

The researchers created a postage-stamp-sized version of the pouch battery that is 10 to 20 times larger than the coin cells made in most university labs. The battery retains 80% of its battery capacity after 6,000 charge and discharge cycles, which is better than other pouch batteries on the market today.

I believe everyone has this experience. After using a mobile phone or computer for a period of time, the battery capacity will decrease and the time it takes to run out of power will also become shorter. One of the major reasons for the decline in lithium battery capacity is the irreversible loss of lithium element. The dendrites on the anode surface are also an irreversible lithium compound, and their growth mechanism is complex. This time, the researchers used a new design to limit the lithiation reaction, prevent dendrite growth, and shorten the time required for battery charging. This new type of battery can empower more electric products. For example, the development of large-capacity, safe and fast-charging batteries can promote the further development of the electric vehicle industry.