A group of researchers from the John A. Paulson School of Engineering and Applied Sciences (SEAS) at Harvard University has developed a lithium metal battery that can be charged and discharged up to 6,000 times. This represents a notable improvement over any other battery on the market and, in addition, it recharges in a matter of minutes.
With their findings, the door opens to the possibility of considerably improving both the manufacturing and the performance and features of electric vehicle batteries. The research, published in Nature Materials, offers a new understanding of the materials for these potentially revolutionary batteries. In turn, it describes a new way of manufacturing solid-state batteries with a metallic lithium anode.
Xin Li, professor and lead author of the study, explains in statements collected by the SEAS website that “lithium metal anode batteries are considered the holy grail of batteries, because they have ten times the capacity of commercial graphite anodes. and could dramatically increase the driving distance of electric vehicles.” Therefore, “our research is an important step towards more practical solid-state batteries for industrial and commercial applications.”
This type of battery faces a challenge in its design: the formation of dendrites on the surface of the anode. As explained by SEAS, these grow like roots in the electrolyte and pierce the barrier that separates the anode from the cathode. As a result, the battery may short circuit or even catch fire.
The example to understand better is that these dendrites adhere to the surface of the anode like plaque on teeth. When discharged, this coating must be removed and if it is damaged, the process can be slow and cause an even more uneven coating on the next charge, reducing the life of the battery.
Li and his team have managed to stop the formation of dendrites by using silicon particles that restrict the lithiation reaction. In this way, a homogeneous coating of a thick layer of lithium metal is favored, so the current density is distributed uniformly, thus avoiding dendrites. Since plating and stripping can occur quickly, the battery recharges in just 10 minutes.
The battery built by the researchers retained 80% of its capacity after 6,000 cycles, a result that surpasses other pouch-type batteries available on the market. In addition, they have discovered other materials that can produce similar performance, opening the way to identifying new materials for battery design.
