Enhanced structural stability and improved electrochemical performance of layered lithium-rich cathode materials via tellurium doping

A series of cathode materials Li_1.2[Mn_0.56Ni_0.16Co_0.08]_1-xTe_xO₂ (x = 0, 0.02, 0.05 and 0.1) were synthesized via co-precipitation. Structural characterization revealed that these Te-doped materials are of a high ordered layer structure with a low level of cation mixing. The electrochemical experiments showed that the Li_1.2[Mn_0.56Ni_0.16Co_0.08]_0.95Te_0.05O₂ sample (denoted as LRMO-Te_0.05) delivers a high initial coulombic efficiency of 88.2% with an initial discharge capacity of 271.6 mAh g⁻¹ at room temperature, an enhanced rate capability of 156.1 mAh g⁻¹ at 5 C, and an excellent cycling stability with an initial capacity of 84.3% after 100 cycles. The outstanding electrochemical properties of Te-doped electrodes can be mainly attributed to the enhanced layered structural stability and low charge transfer resistance as a result of substitution of transition metals by Te⁶⁺. More importantly, voltage decay of the Li_1.2[Mn_0.56Ni_0.16Co_0.08]_1-xTe_xO₂ (x = 0, 0.02, 0.05 and 0.1) materials upon cycling can be effectively restrained by manipulating the charge voltage pattern.