Development of novel cathode materials for Li-ion batteries

New CrO_x modified positive electrodes and quaternary spinels LiCr_yMn_2-yO₄ (y=0.05 to y=0.5) and Li_xCr_yMn_2-yO_4+δ (y=0.02 to 0.1) were synthesized and electrochemically characterized. An increase of O/Cr ratio and the subsequent modification of the oxide increases the capacity of m-CrO_x to 250 mA/g. The average values of these cells is 3.0 V which gives an average power density for m-CrOx of approximately 650 wh/g. The CrO_x doped LiCr_0.1 Mn_1.9O_4.132 that was synthesized using high oxygen pressure showed the best capacity retention. Using seven times higher discharge rate than that for the pure spinel or Cr³⁺ doped spinel (LiCr_0.1Mn_1.9O₄), the capacity of LiCr_0.1Mn_1.9O_4.132 remained almost unchanged after 200 cycles