A novel lithium-ion battery comprising Li-rich@Cr2O5 composite cathode and Li4Ti5O12 anode with controllable coulombic efficiency

Through meticulous design, a Li-lacking Cr2O5 cathode is physically mixed with Li-rich Li1.2Ni0.13Co0.13Mn0.54O2 (LNCM) cathode to form composite cathodes LNCM@xCr2O5 (x = 0, 0.1, 0.2, 0.3, 0.35, 0.4, mass ratio) in order to make use of the excess lithium produced by the Li-rich component in the first charge-discharge process. The initial coulombic efficiency (ICE) of LNCM half-cell has been significantly increased from 75.5% (x = 0) to 108.9% (x = 0.35). A novel full-cell comprising LNCM@Cr2O5 composite cathode and Li4Ti5O12 anode has been developed. Such electrode accordance, i.e., LNCM@Cr2O5//Li4Ti5O12 (“L-cell”), shows a particularly high ICE of 97.7%. The “L-cell” can transmit an outstanding reversible capacity up to 250 mA h g−1 and has 94% capacity retention during 50 cycles. It also has superior rate capacities as high as 122 and 94 mA h g−1 at 1.25 and 2.5 A g−1 current densities, which are even better in comparison of Li-rich//graphite full-cell (“G-cell”). The high performance of “L-cell” benefiting from the well-designed coulombic efficiency accordance mechanism displays a great potential for fast charge-discharge applications in future high-energy lithium ion batteries.