(Invited) Ti-Substituted Li[Li0.26Mn0.6-XTixNi0.07Co0.07]O2 Layered Cathode Material with Improved Structural Stability and Suppressed Voltage Fading

The Lithium ion batteries (LIBs) with intercalated cathodes, such as LiCoO₂ and LiFePO₄, have achieved great success in portable electronic devices. However, they are unsatisfied for the stationary grid storage and electrical vehicles due to their low specific capacity (<160 mAh/g). Recently, Lithium- and Manganese-rich layered oxide cathode has attracted great interest due to its high theoretical specific capacity (~ 240 mAh/g) and high working voltage. However, its real practical application is highly hindered by its poor structure stability and severe voltage fading, which is caused by Mn ion migrating to adjacent lithium ion layers, forming spinel structure. Here, we report Titanium (Ti) substituted Li- and Mn-rich cathode material (Li[Li_0.26Mn_0.6-xTi_xNi_0.07Co_0.07]O₂) through a facile co-precipitation approach. Ti substitution greatly extends the cathode’s cycling life and weakens the voltage fading. Taking the advantage of first-principles analyses of the cohesive energy, phonon force constants, and charge density of these materials, it indicates that Ti substitution increases the stability of the layered structure and prevents Mn ions migration from transitional metal layer to adjacent lithium ion layer. Taking the facile preparation process and much enhanced electrochemical performance into account, it would be of significant interest for scalable fabrication for rechargeable lithium battery.