Korean researchers have used semiconductor technology to improve the safety of Li-ion batteries. A research team from the Korea Institute of Science and Technology (KIST) led by Dr. Joong Kee Lee of the Center for Energy Storage Research has succeeded in inhibiting the growth of dendrites by forming protective semiconducting passivation layers on the surface of Li electrodes. A paper on their work appears in ACS Energy Letters.
To prevent dendrite formation, the research team exposed fullerene (C60), a highly electronic conductive semiconductor material, to plasma, resulting in the formation of semiconducting passivation carbonaceous layers between the Li electrode and the electrolyte.
The semiconducting passivation carbonaceous layers allow Li-ions to pass through while blocking electrons due to generation of Schottky barrier, and by preventing electrons and ions from interacting on the electrode surface and inside, they stop the formation of Li crystals and the consequent growth of dendrites.
The stability of the electrodes with the semiconducting passivation carbonaceous layers was tested using Li/Li symmetric cells in extreme electrochemical environments in which typical Li electrodes remain stable for up to 20 charge/discharge cycles. The newly developed electrodes showed significantly enhanced stability, with Li dendrite growth suppressed for up to 1,200 cycles.
Moreover, using a lithium cobalt oxide (LiCoO2) cathode in addition to the developed electrode, approximately 81% of the initial battery capacity was maintained after 500 cycles, representing an improvement of approximately 60% over conventional Li electrodes.
The effective suppression of dendrite growth on Li electrodes is instrumental for improving battery safety. The technology for developing highly safe Li-metal electrodes proposed in this study provides a blueprint for the development of next-generation batteries that do not pose a fire risk.—Lead researcher Dr. Joong Kee Lee
The team’s next goal is improving the commercial viability of this technology.
We aim to make the fabrication of the semiconducting passivation carbonaceous layers more cost-effective by substituting fullerene with less expensive materials.—Dr. Joong Kee Lee
Ryanda Enggar Anugrah Ardhi, Guicheng Liu, and Joong Kee Lee (2021) “Metal–Semiconductor Ohmic and Schottky Contact Interfaces for Stable Li-Metal Electrodes” ACS Energy Letters 6 (4), 1432-1442 doi: 10.1021/acsenergylett.1c00150