추가 정보 영역
| Speaker |
Dr. Wonchang Choi |
| Affiliation |
KIST |
| Date |
November 1, 2017 |
| Time |
4:00 pm - 5:30 pm |
| Venue |
104-E205 |
| Sponsor |
UNIST-Energy and Chemical Engineering |
| Host |
Prof. Young Sik Kim |
| Contact |
052-217-2921 |
Recently, focusing on the achievement of high power the lithium-ion batteries (LIBs) has been on the rise. Above all, one of the most promise ways to maximize the power capability of LIB is realization of large chemical potential difference between cathode material and anode material. Hence, high-voltage (5 V class) LiNi0.5Mn1.5O4 has been considered as a promising candidate for the cathode material which can applied to the high power LIBs. However, this high-voltage cathode material is suffered from its drawbacks related to side reactions (e.g. electrolyte decomposition, HF attack, Mn dissolution), and these are worsen when the cell operated in the high temperature condition. The thermal instability of the electrode causes serious degradation in the cycling performance. The number of researcher have reported that the surface modification is well known as effective solution to solve problem issues, regarding the failure of high temperature cycling of LiNi0.5Mn1.5O4. Herein, we synthesized LiNbO3-coated LiNi0.5Mn1.5O4 by using the sol-gel assisted solid-state reaction process. Morphological and structural analyses show the sol-gel process ensures conformal and thin LiNbO3 coating layer on the LiNi0.5Mn1.5O4 particles. Well-defined thin coating layer obviously enhanced the electrochemical performances, and effectively protected LiNi0.5Mn1.5O4 from the electrolyte decomposition or further side reactions in the high temperature cycling at 60 ℃. Besides, our optimized 1 wt% LiNbO3-coated LiNi0.5Mn1.5O4 also shows high rate capability due to the LiNbO3’s role of ion-conducting with proper thickness. We expect that our LiNbO3-coated LiNi0.5Mn1.5O4 synthesized by using sol-gel assisted solid-state reaction process has a lot of potential to realize stable high power LIBs as a high temperature durable cathode material.
