Uniform amorphous Mg x B y O z coating combined with V o for highly stable Li-Rich Mn-based cathode material

Li-rich Mn-based cathode materials (LRs) have attracted significant research interests owing to high energy density, but their commercial application is limited by capacity/voltage attenuation caused by irreversible lattice oxygen release, structural reconstruction, interface reactions, as well as the dissolution of transition metals (TM). This work proposed a synergistic modification strategy of surface coating by magnesium borate (Mg x B y O z ) cooperated with defect construction of enriched oxygen vacancy (V o ) for Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode material, and the interior and exterior modification has been achieved in one step through the interaction between reducing agent of BH 4 - and oxygen at surface. The amorphous Mg x B y O z coating with good mechanical strength and toughness provides lasting protection and prevents phase degradation from layered to rock -salt phase. The constructed V o reduce irreversible oxygen release and subsequently slows down capacity decay and voltage degradation. The modified MBO2-LR exhibits superior rate capacity with a specific capacity of 140.6 mAh g -1 at a high current density of 10C and an satisfactory capacity retention of 83.6% after 200 high-voltage cycles at 1C, much higher than the values of the pristine sample. This work offers a viable modifying route for the promising cathode materials with high energy density.