Development of LiNi[sub 0.5]Mn[sub 1.5]O[sub 4]/Li[sub 4]Ti[sub 5]O[sub 12] System with Long Cycle Life

The electrochemical performance of cells with different designs (positive-electrode-limited, negative-electrode-limited, and positive/negative capacity ratio of ) was investigated at different temperatures and current densities. Half-cells based on either LNMO/Li or LTO/Li exhibited an outstanding rate capability. When both electrodes were combined in a full cell configuration, the LNMO/LTO cells showed an excellent rate capability, with 86% discharge capacity retention at the 10C rate. Of the three designs, the negative-limited full cell showed the best cycling performance when discharged at the 2C rate in tests at room temperature: 98% capacity retention after 1000 cycles. The negative-limited full cell also exhibited excellent cycling characteristics in tests at : 95% discharge capacity retention after 200 cycles. These results clearly demonstrate that the LNMO/LTO system with a negative-limited design is attractive for plug-in hybrid electric vehicles, where a long cycle life and a reasonable power are needed.