Synthesis and electrochemical properties of manganese based compounds Na0.6Li0.4Mn0.75O2 and Na0.6Zn0.2Mn0.75O2
By Li, Hang; Liu, Guoqiang; Sun, Lizhu; Qiao, Shiyi; Zhao, Peng; Liu, Hui
Published in Journal of Alloys and Compounds
2019
Abstract
Two new compounds Na0.6Li0.4Mn0.75O2 and Na0.6Zn0.2Mn0.75O2 are synthesized by a simple solid-phase reaction route, and their electrochemical properties are investigated. Their charge-discharge mechanisms are investigated. In the voltage range of 1.5–4.4 V, the initial discharge capacities of Na0.6Li0.4Mn0.75O2 and Na0.6Zn0.2Mn0.75O2 are 128 mAh g−1 and 193 mAh g−1 at a current density of 17 mA g−1, respectively. The cycle performance of Na0.6Li0.4Mn0.75O2 is better than that of Na0.6Zn0.2Mn0.75O2. In the voltage range of 2–4.4 V, the cycle performances of the two compounds Na0.6Li0.4Mn0.75O2 and Na0.6Zn0.2Mn0.75O2 are improved. The Na+ ion diffusion coefficient of Na0.6Zn0.2Mn0.75O2 obtained by alternating current impedance is 9 times that of Na0.6Li0.4Mn0.75O2. The roles of doping Li and doping Zn on the electrochemical properties can be obtained from this study. The charge discharge mechanisms of the two compounds are further studied.