高性能钠离子电池O3型层状正极材料中金属氧配体的共价调控OA

O3-type nickel-manganese-based layered cathodes are appealing for building high-energy sodium-ion batteries(SIBs)in growing energy storage application.However,the complicated phase transitions and sluggish Na+kinetics have largely impeded their practical applications.Herein,this work proposes a dual-site doping strategy for O3-type NaNi0.5 Mn0.5 O2 cathode to regulate the covalency of Ni/Mn-O bonds via reinforcing TM-O bonding strength.The designed O3-Na0.92 Ni0.47 Nb0.03 Mn0.30 Ti0.20O2(NNNMTO)demonstrates an excellent rate capability of 53 mAh/g at 10 C and a long-term cyclic stability of 70%capacity retention after 500 cycles at 2 C under a wide working voltage range between 2.0～4.2 V,along with less moisture sensitivity.Additionally,the full battery paired with commercial hard carbon anode displays an impressive cycling stability with an energy density of 260 Wh/kg based on the active material mass of both electrodes,making its practical operation possible.This work provides insightful perspectives in facilitating Na+diffusion and mitigating the undesirable phase transition for layered oxide cathode materials of high-energy SIBs.