New insights into low temperature properties of Li-rich layered cathode materials

Since Li-ion batteries made of Li-rich layered materials might work at extreme environments, understanding the low temperature properties of Li-rich layered materials is of great importance. In this article, the low temperature properties and corresponding mechanism of Li-rich layered materials with a great amount of activated Li2MnO3 are unraveled through a comparison of the low temperature characteristics of Li-rich layered materials with a small amount of activated Li2MnO3 versus the former. Our findings indicate that in the electrode with a large amount of activated Li2MnO3, the sluggish kinetics of the electrode reaction at low temperatures suppresses greatly the Mn4+/Mn3+ reduction reaction, leading to much smaller initial discharge capacity and much better cyclic performance compared with situations at room temperature. Moreover, the increasingly suppressed Mn4+-/Mn3+ reduction reaction stop the discharge voltage fading, which might mitigate the layered-to-spinel phase transformation. (C) 2017 Published by Elsevier B.V.