Pseudo-Bonding and Electric-Field Harmony for Li-Rich Mn-Based Oxide Cathode

The practical application of Li-rich Mn-based oxide cathode is predominately retarded by the capacity decline and voltage fading, associated with the structure distortion and anionic redox reactions. Here, a linkage-functionalized modification approach to tackle these challenges via a synchronous lithium oxidation strategy is reported. The doping of Ce in the bulk phase activates the pseudo-bonding effect, effectively stabilizing the lattice oxygen evolution and suppressing the structure distortion. Interestingly, it also induces the formation of spinel phase Li₄Mn₅O₁₂ in the subsurface, which in turn constructs the phase boundaries, thereby arousing the interior self-built-in electric field to prevent the outward migration of bulk oxygen anions and boost the charge transfer. Moreover, the formed coating layer Li₂CeO₃ with oxygen vacancies accelerates Li⁺ diffusion and mitigates electrolyte cauterization. The corresponding cathode exhibits superior long-cycle stability after 300 cycles with only a 0.013% capacity drop and 1.76 mV voltage decay per cycle. This work sheds new light on the development of Li-rich Mn-based oxide cathodes toward high energy density applications.