A well-matched MgNiO2 surface heterointerface layer to enhance the cycling stability of cobalt-free Li-rich Mn-based cathode materials

Abstract

The instability of lattice oxygen and the resulting chain reactions mainly originate at the interface between the electrolyte and the outmost surface of Li-rich Mn-based cathode materials (LRM). Although many research works are focused on improving the cycling performances of LRM by surface protection, the issue of voltage fading is still severing. To overcome the challenge, the MgNiO2 surface heterointerface layer is constructed on the surface of cobalt-free LRM to form a heterointerface in this work, which can suppress side reactions at the interface, inhibit the dissolution of Mn elements, enhance the lattice oxygen stability, and stabilize the crystal structure. Benefiting from the above merits, the voltage fading value of the modified sample has been decreased by 28.2%. And the specific capacity retention of the modified sample (92.9%) is significantly higher than that of the pristine sample (80.9%). This work provides a valuable idea for optimizing the surface to improve the electrochemical performance of high-specific capacity Li-rich cathode materials.