Effect of Carbonate and Spinel Surface Modification on Structure and Electrochemical Performance of Li-rich Layered Oxide Li[Li0 2Ni0 2Mn0 6]O2

Abstract

Lithium-rich cathode material is one of the most potential cathode material for lithium ion battery due to its high specific capacity and high voltage compares to other cathode materials However as the charge and discharge cycle goes on phase transition will happen in this material and the original layered structure will transform to spinel structure which makes the capacity decreasing As a result figuring out mechanisms of phase transition and finding a way to prevent phase transition is very critical In the first part of this thesis we discuss the influences of different phases and formation of impurities on electrochemical performance under different annealing temperature In the second part of this thesis we use precipitation methods to coat spinel and carbonate materials on our lithium-rich cathode material For the carbonate-coating sample the charge retention after 60 cycles is estimated to be 82% This result shows that the carbonate-coating method could prevent phase transition and promote the battery efficiency

Date of Award	2019
Original language	English
Supervisor	Chuan-Pu Liu (Supervisor)