A highly stable Mn-based cathode with low crystallinity Li2MnO3 and spinel functional units for lithium-ion batteries

Abstract

Mn-based oxide cathodes have emerged as potentially feasible cathode materials for high-specific-energy Li-ion batteries due to their cost-efficiency and exceptionally high capacity via the concomitant cationic and anionic redox reactions. However, their practical implementation is still challenging since the trade-off between the electrochemical behaviours and structural stability hinders them from realizing the coinstantaneous high capacity and lifespan. Herein, a structural and crystalline design is introduced into Li_0.67Li_0.2[Mn_0.8Ni_0.2]_0.8O₂, presenting low crystallinity layered Li₂MnO₃ and pre-introduced high-voltage spinel intergrown functional units in the Mn-based composite-structure oxide cathode. This scenario shows no capacity decay within the high-voltage cycling up to 5.0 volt versus Li/Li⁺, a high energy density of 870 W h kg⁻¹, a low-strain behaviour, and high lithium mobility for high cycling rates. This study provides a solid perspective on the design of Mn-based cathode materials by incorporating distinct functional units and tailoring their configurations, which is conducive to facilitating prolonged Li intercalation chemistry.