Synthesis of (1-2x) LiNi_(1/2)Mn_(1/2)O_2 centre dot x-Li[Li_(1/3)Mn_(2/3)]O_2 centre dot LiCoO_2 (0 < = x < = 0.5) electrode materials and comparative study on cooling rate

摘要

Layered cathode materials with the nominal compositions of (1 -- 2A-) LiNi_(1/2)Mn_(1/2)O_2 centre dot xLi[Li_(1/3)Mn_(2/3)]O_2 centre dot LiCoO_2 (0 < = x < = 0.5) were synthesized by a simple solid-state reaction on the basis of good structural compatibility between the three layered compounds. LiNi_(1/2)Mn_(1/2)O_2, Li[Li_(1/3)Mn_(2/3)]O_2, and LiCoO_2. Increasing contents of Li[Li_(1/3)Mn_(2/3)]O_2 and LiCoO_2 in the materials decreased the occupancy of transitional metal ions in Li layers and thus remarkably improved electrochemical performances; but it also brought about an irreversible initial charge plateau when x reached 0.3. The comparative studies on cooling rates showed that different cooling rates in the material preparation hardly gave different electrode performances.