Structure and electrochemistry of B doped Li(Li 0.2 Ni 0.13 Co 0.13 Mn 0.54 ) 1-x B x O 2 as cathode materials for lithium-ion batteries

Abstract Migration of transition metal (TM) ions to tetrahedral sites plays a crucial role on structural transformation and electrochemical behaviors for Li-rich layered oxides. Here, incorporating small B 3+ in the tetrahedral interstice is employed to block the migration channel of TM ions and stabilize the crystal structure. Benefiting from their good structural stability, Li-rich layered materials with B-doped Li 1.198 Ni 0.129 Co 0.129 Mn 0.535 B 0.01 O 2 and Li 1.196 Ni 0.127 Co 0.127 Mn 0.529 B 0.02 O 2 , exhibit excellent cycling performance and voltage stability. After 51 cycles at 0.2 C, 1 mol.% boron incorporated sample can deliver 211 mAh g −1 with capacity retention of 89.9%, which is much higher than that of the undoped sample of 177 mAh g −1 with the retention of 79.2%. Moreover, the declined voltage per cycle decreases from 3.6885 mV to 2.7530 mV after 2 mol.% boron doping. XRD patterns after extended cycling verified the suppression of the structural transformation by the incorporation of boron.