THE POSSIBILITY OF Na SUBSTITUTION FOR Li ON THE MANGANNESE OXIDES USED AS CATHODE ELECTRODES IN ALKALINE ION BATTERIES
Abstract
Li-ionized Ni (LiNi0.1Mn1.9O4) material was synthesized at 700°C by the solgel method from lithium acetate, manganese acetate and nickel acetate. The XRD spectrum confirms the spinel-derived samples of LiNi0.1Mn1.9O4 without any impurities. SEM images confirm that the materials were formed in particles with several dozen nanometers. The ion conductivity reached otp = 19.773×10-5 S.cm-1, the maximum discharge capacity was 85.5 mAh/g and 79.7 mAh/g, respectively. This value is about 70% of theoretical capacity. Materials based on hydroxide manganese oxide synthesized by the hydrothermal method at 205 °C and then annaealed at 600 °C for re-crystallized leaded to nanowire form with a size of 30 nm and a length of several hundred nm to several μm. The ion conductivity is otp = 31.661×10-5 S.cm-1. Results of the discharge test of the Na0.44MnO2 cathode electrodes in the sodium ion battery configuration showed highest charge and discharge capacities. They were 67.5 mAh/g and 65.8 mAh/g, respectively. Capacity is maintained around 85.3% after 50 cycles. The Coulomb performance reaches 90% in 70 cycles.
