Knowledge Bank

Energy and environmental quality have become the major thrust areas for modern society. For more than one century, internal combustion engines that rely on fossil fuels have been dominant power sources in transportation sectors. Unfortunately, it caused severe environmental concerns such as air-pollution and global warming. To mitigate such problems, vehicle electrification and improving fuel efficiency have been a major trend in the market, led by government through policies and regulations. Although the research on lithium batteries is relatively mature, solid-state lithium batteries have received more and more attention from researchers these days. The market for electric vehicles needs to overcome many technical issues of solid-state batteries, such as cycle life, energy densities, and rate capabilities. It is urgent for us to develop the promising cathode materials for solid-state batteries. Spinel LiCo1-xAlxO2 was recently discovered by Argonne National Lab as a zero-strain cathode material for Li-ion batteries. Its low volume change (∆V ≤ 0.02%) offers an excellent mechanical stability of the cathodes during electrochemical cycling. In this study, a formation of a new substance named Co3O4 at the surface of cycle-aged LiCo1-xAlxO2 was first reported that can be associated with an electrochemical degradation during extended period of cycling. To address this issue, I applied LiNbO3 coating on the spinel LiCo1-xAlxO2 powders as an approach to stabilize its cathode-electrolyte interphase (CEI). Structural and microscopy characterizations revealed the presence of homogeneous LiNbO3 coating on the spinel powders. Raman spectroscopy and electrochemical characterizations demonstrate the exciting results that LiNbO3 coating can successfully suppress unwanted reactions occurring at the CEI and thereby improves cycle-life and rate-capabilities of battery cells. This study will promote research and development of the zero-strain cathode materials for solid-state batteries.