Reaching High Stable Specific Capacity with Integrated xLi₂MnO₃:(1-x)LiNi_0.6Co_0.2Mn_0.2O₂ (x=0.6) Cathode Materials for Li-ion Batteries

The work described herein aimed at searching guidelines for optimal selection of high specific capacity cathode materials for Li ion batteries. Among the cathodes for lithium-ion batteries, Mn and Ni-rich Li1+xNi_yMn_zCo_1‑y‑zO₂ (x<0.2, y> 0.5) materials have attracted a attention as promising candidates due to their high capacity, low cost, good cycling stability, and safety. In this study, we compared the electrochemical behavior of 3 cathode materials working at wide potential domains in Li cells: Li_1.2Ni_0.24Co_0.08Mn_0.48O₂ (0.6Li₂MnO₃:0.4LiNi_0.6Co_0.2Mn_0.2O₂), Li_1.2Ni_0.16MCo_0.08Mn_0.56O₂ (0.6Li₂MnO₃:0.4LiNi_0.4MCo_0.2Mn_0.4O₂) and LiNi_0.6Co_0.2Mn_0.2O₂ as a reference material. The former two compositions are Li and Mn rich cathode materials which comprise initially Li₂MnO₃ and LiNi_xCo_1-x-yMn_yO₂ components as established by structural analysis using X-ray and electron diffraction. The main focus was on the possibility to obtain stable capacity and average voltage while working at a wide potential domain, in order to extract high specific capacity. The three materials were prepared by the self-combustion reaction (SCR) and were characterized by SEM, ICP, HRTEM and electrochemical techniques. Li_1.2Ni_0.24MCo_0.08Mn_0.48O₂ cathodes operating in the potential range 2-4.6 V vs. Li demonstrated stable specific capacity > 200 mAh g^-1 and stable average voltage thus rivaling LiNi_0.6Co_0.2Mn_0.2O₂ and Li_1.2Ni_0.16MCo_0.08Mn_0.56O₂ cathodes in terms of electrochemical performance. The consequences of these findings are discussed herein. Li and Mn rich cathode materials may be advantageous over the Ni-rich cathode materials in terms of cost and safety. The results obtained will be discussed in the poster presentation.