Composite positive electrode material and preparation method thereof, positive electrode plate, secondary battery, and electric apparatus

A composite positive electrode material, wherein:

• a span of the composite positive electrode material is 1.2-2.0, wherein the span=(Dv90−Dv10)/Dv50, and Dv90, Dv10, and Dv50 are a particle volume distribution Dv90, a particle volume distribution Dv10, and a volume median diameter Dv50 of the composite positive electrode material;
• and
• the composite positive electrode material comprises a first lithium-rich manganese-based positive electrode material and a second lithium-rich manganese-based positive electrode material, wherein:
• primary particles of the first lithium-rich manganese-based positive electrode material are rod-like particles, a length of the rod-like particle is 0.1-1.5 μm, and a volume median diameter Dv50 of secondary particles of the first lithium-rich manganese-based positive electrode material is 3-8 μm;
• and
• primary particles of the second lithium-rich manganese-based positive electrode material are spheroidal particles, a diameter of the spheroidal particle is 0.1-400 nm, and a volume median diameter Dv50 of secondary particles of the second lithium-rich manganese-based positive electrode material is 8-20 μm.