Positive electrode active material and preparation method therefor, sodium ion battery, and apparatus comprising sodium ion battery

A positive electrode active material satisfying the chemical formula LxNayMzCuαFeβMnγO2+δ−0.5ηXη, wherein

• L is a doping element at alkali metal site and selected from one or more of Li+, K+, Mg2+, Ca2+ and Zn2+;
• M is a doping element at transition metal site and selected from one or more of Li+, Ni2+, Mg2+, Mn2+, Zn2+, Co2+, Ca2+, Ba2+, Sr2+, Mn3+, Al3+, B3+, Cr3+, V3+, Zr4+, Ti4+, Sn4+, V4+, Mo4+, Mo5+, Ru4+, Nb5+, Si4+, Nb6+, Mo6+ and Te6+;
• X is a doping element at oxygen site and selected from one or more of F−, Cl−, Br− and I−,
• 0≤x≤0.35, 0.65≤y≤1, 0<α≤0.3, 0<β<0.5, 0<γ<0.5, −0.03<δ<0.03, 0≤η≤0.1, and z+α+β+γ=1;
• and mx+y+nz+2α+3β+4γ=2(2+δ), m is the valence state of L, and n is the valence state of M;
• the positive electrode active material has a pH value of from 10.5 to 13;
• and
• an interlayer spacing d003 between two crystal planes (003) of the positive electrode active material is from 5.40 Å to 5.50 Å.