Despite the rapid development of electric vehicles, concerns remain about the safety of lithium-ion batteries, whose dendrites have multiple branches that can cause electric vehicle batteries to catch fire. It is understood that South Korean researchers have used semiconductor technology to improve the safety of lithium batteries. A research team at the Korea Institute of Science and Technology has succeeded in suppressing the growth of dendrites by forming a protective semiconductor passivation layer on the surface of a lithium electrode.
When a lithium battery is charged, lithium ions are transported to the anode and deposited on the surface in the form of lithium metal, forming a tree-like structure. These lithium dendrites cause uncontrollable volume fluctuations and lead to reactions between the solid electrode and the liquid electrolyte, which can cause fires.
To prevent the formation of dendrites, the team exposed fullerenes, a highly electronically conductive semiconductor material, to the plasma, resulting in the formation of a semiconducting passivating carbonaceous layer between the lithium electrode and the electrolyte. The semiconducting passivation carbonaceous layer allows the passage of lithium ions, while blocking electrons due to the appearance of the Schottky barrier, and preventing electrons and ions from interacting with each other on the surface and inside of the electrode, thereby preventing the formation of lithium crystals and the growth of dendrites.
The stability of electrodes with semiconducting passivating carbide layers was tested in extreme electrochemical environments using lithium symmetric cells, where typical lithium electrodes remained stable for up to 20 charge/discharge cycles; while the newly developed electrodes were stable The performance was significantly enhanced, and Li dendrite growth was suppressed up to 1200 charge-discharge cycles. Furthermore, using the lithium cobalt oxide cathode, in addition to the developed electrodes, maintained about 81% of the initial battery capacity after 500 cycles, an improvement of about 60% over conventional lithium electrodes.
Effectively suppressing dendrite growth on lithium electrodes contributes to improving the safety of batteries. The technology proposed in this study to develop highly safe lithium metal electrodes provides a blueprint for developing next-generation batteries that pose no fire risk.
The next goal of the research team is to improve the commercial viability of the technology.
