In this work, novel composition of Nax[Ni0.6Co0.2Mn0.2]O2 (x = 0.5 and 1.0) layered cathode materials were synthesized by using hydroxide co-precipitation and calcined at 850, 900 and 950 °C. We studied the effects of different sodium contents and calcination temperature on the structural and electrochemical properties of this novel cathode material. The change of calcination temperature and sodium content led to different P2-type, P2/P3-type, P2/O3-type, or O3-type structures. The results indicate better electrochemical perfor-mance of the P2-type cathode materials in terms of high discharge capacity and good cycling performance, when compared to P2/P3, P2/O3, and O3-type cathode materials. Na0.5[Ni0.6Co0.2Mn0.2]O2 electrode calcined at 900 °C exhibited a good capacity of 107.15 mAhg-1 and ca-pacity retention over 73 % after 20 cycle. Characterization of this material will help to develop cathode materials for the Na-ion battery cathode.

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Using LiNi0.8Co0.1Mn0.1O2 as a starting material, a surface-modified cathode material was obtained by coating it with a nanolayer of amorphous carbon, where the added C12H22O11 (sugar) was transformed to Li2CO3 compounds after reacting with residual LiOH on the surface. A thin and uniformly smooth nanolayer (35 nm thick) was observed on the surface of the LiNi0.8Co0.1Mn0.1O2, as confirmed by transmission electron microscopy (TEM). The amount of residual lithium hydroxide (LiOH) was significantly reduced through the formation of lithium carbonate (Li2CO3). As a result, carbon-coated LiNi0.8Co0.1Mn0.1O2 exhibited noticeable improvement in capacity and rate capability and much lower exothermic heat in the charged state at 4.3V. The improved electrochemical performance and thermal stability are attributed to the carbon coating, which reduced the residual lithium hydroxide, protected the cathode material from reacting with the electrolyte, and slowing the incrassation of the solid electrolyte interphase (SEI) film on the surfaces of the oxide particles.C12H22O11 + 12O2 → 12CO2 + 11H2OPACS number: 73.20.At

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In this study, high nickel layered LiNi