Layered-spinel capped nanotube assembled 3D Li-rich hierarchitectures for high performance Li-ion battery cathodes

While Li-rich Mn-based layered oxide is an appealing candidate for high energy density and high-voltage cathode materials for Li-ion batteries (LIBs), its applications are severely restricted by its low coulombic efficiency and poor rate capability. Herein, we report an effective approach to fabricate layered-spinel capped nanotube assembled 3D Li-rich hierarchitectures, by using a hydrothermal and ionic interfusion method. The unique 3D hollow hierarchical structure of the resulting material greatly shortens the pathways of electron and ion transfer, while maintaining reliable structural stability. Moreover, layered-spinel multicomponents introduce more effective 3D Li-ion diffusion channels (an excellent Li-ion diffusion coefficient of 1.55 × 10^-10 cm² s^-1) and offer high coulombic efficiency. The structure-composition-property relationship is investigated by hierarchical structure controllable synthesis, Rietveld refinement crystallographic analysis and Li-ion transport kinetics measurement. As a result, when utilised as a cathode material for LIBs, this 3D Li-rich hierarchitecture delivers a high capacity of 293 (±3) mA h g^-1 at 0.1C, shows a superior capacity retention of 89.5% after 200 cycles at 1C and exhibits a high capacity of 202 (±3) mA h g^-1 even at 5C.