Enhanced Structural Stability and Improved Electrochemical Performance of Layered Lithium-Rich Cathode Materials via Tellurium Doping

A series of cathode materials Li1.2[Mn0.56Ni0.16Co0.08]1-xTexO2 (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 Li1.2[Mn0.56Ni0.16Co0.08]0.95Te0.05O2 sample (denoted as LRMO-Te0.05) 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 Li1.2[Mn0.56Ni0.16Co0.08]1-xTexO2 (x = 0, 0.02, 0.05 and 0.1) materials upon cycling can be effectively restrained by manipulating the charge voltage pattern.